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WCDMA RAN Planning and Optimization (Book2 Design and Planning)

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WCDMA RNP
Fundamental
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Objectives
z
Upon completion of this course, you will be able to:
‡
Get familiar with principles of radio wave propagation, and
theoretically prepare for the subsequent link budget.
‡
Introduce the knowledge about antennas and the meanings of
typical indices.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page2
Contents
1. Radio Wave Introduction
2. Antenna
3. RF Basics
4. Symbol Explanation
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Page3
Contents
1. Radio Wave Introduction
1.1 Basic Principles of Radio Wave
1.2 Propagation Features of Radio Wave
1.3 Propagation Model of Radio Wave
1.4 Correction of Propagation Model
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Page4
Radio Wave Spectrum
Frequency
3-30Hz
30-300Hz
300-3000Hz
3-30KHz
30-300KHz
300-3000KHz
3-30MHz
30-300MHz
300-3000MHz
3-30GHz
30-300GHz
Classification
Designation
Extremely Low
Frequency
Voice Frequency
Very-low Frequency
Low Frequency
Medium Frequency
High Frequency
Very High Frequency
Ultra High Frequency
Super High Frequency
Extremely High
Frequency
ELF
VF
VLF
LF
MF
HF
VHF
UHF
SHF
EHF
300-3000GHz
The frequencies in each specific band present unique propagation features.
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Page5
The radio waves are distributed in 3Hz ~ 3000GHz. This spectrum is divided
into 12 bands, as shown in the above table. The frequencies in each specific
band present unique propagation features: The lower the frequency is, the
lower the propagation loss will be, the farther the coverage distance will be,
and the stronger the diffraction capability will be. However, lower-band
frequency resources are stringent and the system capacity is limited, so they
are primarily applied to the systems of broadcast, television and paging. The
higher-band frequency resources are abundant and the system capacity is large;
however, the higher the frequency is, the higher the propagation loss will be,
the shorter the coverage distance will be, and the weaker the diffraction
capability will be. In addition, the higher the frequency is, the higher the
technical difficulty will be, and the higher the system cost will be. The band
for purpose of the mobile communication system should allow for both
coverage effect and capacity. Compared with other bands, the UHF band
achieves a good tradeoff between the coverage effect and the capacity, and is
hence widely applied to the mobile communication field. Nevertheless, with
the increase of mobile communication demand, more capacity is required. The
mobile communication system is bound to develop toward the high-frequency
band.
Propagation of Electromagnetic Wave
z
When the radio wave propagates in the air, the electric field direction
changes regularly. If the electric field direction of radio wave is vertical to
the ground, the radio wave is vertical polarization wave
‡
If the electric field direction of radio wave is parallel with the ground, the radio
wave is horizontal polarization wave
Dipole
Magnetic Field
Magnetic Field
Electric Field
Electric Field
Electric Field
electric wave transmission direction
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Page6
Propagation of electromagnetic propagation takes on an energy propagation
mode. During the propagation, the electric field is vertical to the magnetic
field, both vertical to the propagation direction. Through interaction between
the electric field and the magnetic field, the energy is propagated to the
distance, just like propagation of water waves.
Propagation Path
Perpendicular incidence wave
and ground refraction wave
(most common propagation modes)
Troposphere reflection wave
(the propagation is very random)
Mountain diffraction wave
(shadow area signal source)
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Ionosphere refraction wave
(beyond-the-horizon communication path)
Page7
Radio wave can be propagated from the transmitting antenna to the receiving
antenna in many ways: perpendicular incidence wave or ground refraction
wave, diffraction wave, troposphere reflection wave, ionosphere reflection
wave, as shown in the diagram. As for radio wave, the most simple
propagation mode between the transmitter and the receiver is free space
propagation. One is perpendicular incidence wave; the other is ground
reflection wave. The result of overlaying the perpendicular incidence wave
and the reflection wave may strengthen the signal, or weaken the signal,
which is known as multi-path effect. Diffraction wave is the main radio wave
signal source for shadow areas such building interior. The strength of the
diffraction wave is much dependent of the propagation environment. The
higher the frequency is, the weaker the diffraction signal will be. The
troposphere reflection wave derives from the troposphere. The heterogeneous
media in the troposphere changes from time to time for weather reasons. Its
reflectance decreases with the increase of height. This slowly changing
reflectance causes the radio wave to curve. The troposphere mode is
applicable to the wireless communication where the wavelength is less than
10m (i.e., frequency is greater than 30MHz).Ionosphere reflection propagation:
When the wavelength of the radio wave is less than 1m (frequency is greater
than 300MHz), the ionosphere is the reflector. There may be one or multiple
hops in the radio wave reflected from the ionosphere, so this propagation is
applicable to long-distance communication. Like the troposphere, the
ionosphere also presents the continuous fluctuation feature.
Propagation Path
①
②
③
④
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Building reflection wave
Diffraction wave
Direct wave
Ground reflection wave
Page8
In a typical cellular mobile communication environment, a mobile station is
always far shorter than a BTS. The direct path between the transmitter and the
receiver is blocked by buildings or other objects. Therefore, the
communication between the cellular BTS and the mobile station is performed
via many other paths than the direct path. In the UHF band, the
electromagnetic wave from the transmitter to the receiver is primarily
propagated by means of scattering, namely, the electromagnetic wave is
reflected from the building plane or refracted from the man-made or natural
objects.
Contents
1. Radio Wave Introduction
1.1 Basic Principles of Radio Wave
1.2 Propagation Features of Radio Wave
1.3 Propagation Model of Radio Wave
1.4 Correction of Propagation Model
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Page9
Radio Propagation Environment
z
Radio wave propagation is affected by topographic structure
and man-made environment. The radio propagation
environment directly decides the selection of propagation
models. Main factors that affect environment are:
‡
Natural landform (mountain, hill, plains, water area)
‡
Quantity, layout and material features of man-made buildings
‡
Natural and man-made electromagnetic noise conditions
‡
Weather conditions
‡
Vegetation features of the region
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Page10
The radio wave is largely affected by the topography and man-made
environment. The natural landforms such as mountains and hills as well as
man-made buildings affect the propagation features of radio waves. Weather
and time conditions also affect propagation of radio wave. For example, the
ionosphere is relatively stable at night, so the shortwave radio is well received.
Landform Categories
Quasi-smooth landform
T
R
The landform with a slightly rugged surface and
the surface height difference is less than 20m
Irregular landform
The landforms apart from quasi-smooth landform
T
are divided to: hill landform, isolated hills, slant
R
landform, and land & water combined landform
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Page11
The quasi-smooth landform refers to the landform with a slightly rugged
surface, and the surface height difference is less than 20m. The average
surface height difference is slight. The Okumura propagation model defines
the roughness height as the difference between 10% and 90% of the landform
roughness in 10km in front of the mobile station antenna. CCIR defines it as
the difference between the height over 90% and the height over 10% of
landform height at 10~50 km in front of the receiver. Other landforms than
abovementioned are called “irregular landforms”.
Signal Fading
Receiving power (dBm)
-20
fast fading
slow fading
-40
-60
10
20
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30
distance (m)
Page12
Slow fading: In case shadow effect is caused by obstacles, and the receiving
signal strength decreases but the field strength mid-value changes slowly with
the change of the topography, the strength decrease is called “slow fading” or
“shadow fading”. The field strength mid-value of slow fading takes on a
logarithmic normal distribution, and is related to location/locale. The fading
speed is dependent on the speed of the mobile station.
Fast fading: In case the amplitude and phase of the combined wave change
sharply with the motion of the mobile station, the change is called “fast
fading”. The spatial distribution of deep fading points is similar to interval of
half of wavelength. Since its field strength takes on Rayleigh distribution, the
fading is also called Rayleigh fading. The amplitude, phase and angle of the
fading are random.
Fast fading is subdivided into the following three categories:
Time-selective fading: In case the user moves quickly and causes Doppler
effect on the frequency domain, and thus results in frequency diffusion, timeselective fading will occur.
Space-selective fading: The fading features vary between different places and
different transmission paths.
Frequency-selective fading: The fading features vary between different
frequencies, which results in delay diffusion and frequency-selective fading.
In order to mitigate the influence of fast fading on wireless communication,
typical methods are: space diversity, frequency diversity, and time
diversity.
Signal Diversity
Measures against fast fading --- Diversity
z
Time diversity
z
Space diversity
z
Frequency diversity
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Page14
To resist such kind of fast fading, the BTS adopts the time diversify, space
diversity (polarization diversity), and frequency diversity.
Time diversity uses the methods of symbol interleaving, error check and error
correction code. Each code has different anti-fading features.
Space diversity uses the main/diversity antenna receiving. The BTS receiver
handles the signals received by the main and diversity antennas respectively,
typically in a maximum likelihood method. This main/diversity receiving
effect is guaranteed by the irrelevance of main antenna receiving and diversity
antenna receiving. Here “irrelevance” means the signals received by the main
antenna and the signals received by the diversity antenna do not have the
feature of simultaneous attenuation. This requires the interval between the
main antenna and the diversity antenna in case of space diversity to be greater
than 10 times of the radio signal wavelength (for GSM, the antenna interval
should be greater than 4m in a distance of 900m, and greater than 2m in a
distance of 1800m). Alternatively, the polarization diversity method should be
used to ensure that signals received by the main and diversity antennas do not
have the same attenuation features. As for mobile stations (mobile phones),
only one antenna exists, so this space diversity function is not supported. The
BTS receiver’s capability of balancing the signals of different delays in a
certain time range (time window) is also a mode of space diversity. In case of
soft switch in the CDMA communication, the mobile station contacts multiple
BTSs concurrently,
and selects the best signals from them, which is also a mode of space
diversity.
Frequency diversity is performed primarily by means of spreading. In the
GSM communication, it simply uses the frequency hopping to obtain the
frequency hop gain; in the CDMA communication, since every channel
works at a broad band (WCDMA has a band of 5MHz), the communication
itself is a kind of spreading communication.
Radio Wave Delay Extension
z
Deriving from reflection, it refers to the co-frequency interference
caused by the time difference in the space transmission of main
signals and other multi-path signals received by the receiver
z
The transmitting signals come from the objects far away from the
receiving antenna
Solution
RAKE
RAKEtechnology
technology
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Page16
Radio wave delay extension—Another type of frequency-selective fading. The
spatial distribution of deep fading points is similar to interval of half of a
wavelength (17cm for 900MHz, 8cm for 1800/1900MHz). If the mobile
station antenna is located at this deep fading point at this time (when the
mobile user in a car resides in this deep fading point in case of a red light, we
call it “read light problem”), the voice quality is very poor, and relevant
technologies should be used to resolve it, e.g., the Rake technology in CDMA
system.
Diffraction Loss
z
The electromagnetic wave diffuses around at the diffraction
point
z
The diffraction wave covers all directions except the obstacle
z
The diffusion loss is most severe
T
R
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Page17
When analyzing the transmission loss in the mountains or the built-up
downtowns, we usually need to analyze the diffraction loss and penetration
loss. Diffraction loss is a measure for the obstacle height and the antenna
height. The obstacle height must be compared with the propagation
wavelength. The diffraction loss generated by the height of the same obstacle
for the long wavelength is less than that for short wavelength. Diffraction loss
is caused the electromagnetic wave being scattered around at the diffraction
point, and the diffraction wave covers all directions except the obstacle. This
diffusion loss is most severe, and the calculation formula is complicated and
varies with different diffraction constants.
Penetration Loss
z
Penetration loss caused by obstructions:
WdBm
XdBm
Penetration
Penetrationloss
loss=X-W=B
=X-W=BdB
dB
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Page18
Indoor penetration loss refers to the difference between the average signal
strength outside the building and the average signal strength of one layer of
the building.
Penetration loss represents the capability of the signal penetrating the building.
The buildings of different structures affect the signals significantly. The
penetration loss generated by the long wavelength is greater than that
generated by the short wavelength of the same building. The incidence angle
of the electromagnetic wave also affects the penetration loss considerably.
Typical Penetration loss:
z
Wall obstruction : 5~20dB
z
Floor obstruction : >20dB
z
Indoor loss value is the function of the floor number : -1.9dB/floor
z
Obstruction of furniture and other obstacles: 2~15dB
z
Thick glass : 6~10dB
z
Penetration loss of train carriage is :15~30dB
z
Penetration loss of lift is : 30dB
z
Dense tree leaves loss : 10dB
Contents
1. Radio Wave Introduction
1.1 Basic Principles of Radio Wave
1.2 Propagation Features of Radio Wave
1.3 Propagation Model of Radio Wave
1.4 Correction of Propagation Model
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Page19
Propagation model
z
Propagation model is used for predicting the medium value of path loss.
The formula can be simplified under if the heights of UE and base station
are given
PathLoss = f (d , f )
where: d is the distance between UE and base station, and
frequency
z
f
is the
Propagation environment affect the model, and the main factors are :
‡
Natural terrain, such as mountain, hill, plain, water land, etc…;
‡
Man-made building (height, distribution and material);
‡
Vegetation;
‡
Weather;
‡
External noise
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Page20
If the heights of UE and BTS are given and ignore the environment affect, the
path loss is just related with the distance between UE and BTS and radio
frequency.
Free Air Space Model
Lo=91.48+20lgd, for f=900MHz
Lo=97.98+20lgd, for f=1900MHz
z
Free space propagation model is applicable to the wireless
environment with isotropic propagation media (e.g.,
vacuum), and is a theoretic model
z
This environment does not exist in real life
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Page21
Free space means an infinite space full of even, linear, isotropic ideal media,
and is an ideal situation. For example, the radio wave propagation of satellite
is very similar to the propagation condition of free space. As seen from the
above formula, once the distance is doubled, the loss will increase by 6dB. If
the frequency is doubled, as shown in the above example, the 1900MHz loss
will be 6dB more than the 900MHz loss.
Flat Landform Propagation Model
Ploss = L0+10χlgd -20lghb - 20lghm
χ : Path loss gradient , usually is 4
T
hb: BTS antenna height
hm:mobile station height
R
L0:parameters related to frequency
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Page22
In the flat landform propagation model, in addition to the frequency and
distance, we also consider the heights of the UE and BTS. Once the BTS
antenna height is doubled, the path loss will be compensated for by 6dB.
Okumura-Hata Model
Application Scope
z
Frequency range
f:150~1500MHz
z
BTS antenna height
Hb:30~200m
z
Mobile station height Hm:1~10m
z
Distance
d:1~20km
Characteristic
z
z
z
z
Macro cell model
The BTS antenna is taller than the surrounding buildings
Predication is not applicable in 1km
Not applicable to the circumstance where the frequency is
above 1500MHz
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Page23
The Okumura-Hata model is commonly used in the planning software. It is
applicable to the micro cell that covers more than 1km below 1500MHz. In
1960s, Okumura and his men used a broad range of frequencies, heights of
several fixed stations and heights of several mobile stations to measure the
signal strength in all kinds of irregular landforms and environments, and
developed a series of curves, then set up a model by fitting the curves to
obtain the empiric formula of propagation model. This model has been widely
used across the globe, and is applicable to areas outside Tokyo by use of the
correction factor.
COST 231-Hata Model
Application Scope
z
Frequency range
f:1505~2000MHz
z
BTS antenna height
Hb:30~200m
z
Mobile station height Hm:1~10m
z
Distance
d:1~20km
Characteristic
z
z
z
z
Macro cell model
The BTS antenna is taller than the surrounding buildings
Predication is not applicable in 1km
Not applicable to the circumstance where the frequency is
above 2000MHz or below 1500MHz
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Page24
The COST231 model is applicable 1500-2000MHz, and is not accurate within
1km. The COST231-hata model is based on the test results of Okumura, and
works out the suggested formula by analyzing the propagation curve of higher
bands.
COST 231 Walfish-Ikegami Model
Application Scope
z
Frequency range :
800~2000MHz
z
BTS antenna height Hbase :
z
Mobile station height Hmobile : 1~3m
z
Distance d :
4~50m
0.02~5km
Characteristic
z
Urban environment, macro cell or micro cell
z
Not applicable to suburban or rural environment
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Page25
The COST231 propagation model team of the European Research Committee
puts forward the following two suggested models: One is based on the Hata
model, and works out the frequency coverage extends from 1500MHz to
2000MHz by using some correction items. However, in all the test
environments, the BTS is taller than the surrounding buildings, so it is not
appropriate to extend the valid range to the circumstance where the BTS
antenna is lower than the surrounding buildings. This model is applicable to
“large-cell macro cell”. In the “micro cell”, the BTS antenna is lower than the
roof, so the Committee created the “COST-Walfish-Ikegami” model according
to the results of Walfish’s calculation of the urban environment, the Ikegami’s
corrective function for handling the street direction and the test data. This
model is tested in a German city Mannheim, and more improvements are
found to be made. When using the model, some parameters that describe the
urban environment features may be required: Building height Hroof (m)
Pavement width w (m) Building interval b (m) Street direction against the
perpendicular incidence wave direction α ( ° )
Standard Propagation
Experimental formula
PathLoss = K1 + K 2 log(D ) + K 3 log(H Txeff ) + K 4 × Diffraction loss
+ K 5 log(D ) × log(H Txeff ) + K 6 (H Rxeff ) + K clutter f (clutter )
Explanation
K1:
K2:
D:
K3:
HTxeff:
K4:
K5:
K6:
Propagation path loss constant value
log(d) correction factor
Distance between receiver and transmitter (m)
log(HTxeff) correction factor
Transmitter antenna height (m)
Diffraction loss correction factor
log(HTxeff)log(D) correction factor
Correction factor
H Rxeff : Receiver antenna height (m)
Kclutter: clutter correction factor
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Page26
Using the multiplier factor configured by customer, the propagation model can
be made by order totally. It can support using different K1 and K2 according
to distance and LOS or NLOS. It also can use different diffraction loss
algorithm and effective BTS height algorithm. One optional amendment
condition is that U-net can amend the path loss of hilly terrains environments
under it is LOS between transmitter and receiver.
Contents
1. Radio Wave Introduction
1.1 Basic Principles of Radio Wave
1.2 Propagation Features of Radio Wave
1.3 Propagation Model of Radio Wave
1.4 Correction of Propagation Model
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Page27
Basic Principles and Procedures
Target propagation environment
Selected propagated environment
CW data collection
parameter setting
Measured propagation path loss
Forecast propagation path loss
Comparison
Error compliant with
requirements?
End
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Page28
Due to difference of propagation environment, the propagation model
parameters must be corrected based on measured values, so as to embody the
radio wave propagation features of the actual environment. Generally, we use
the Continuous Wave (CW) test method to measure the propagation path loss
in the actual environment. By comparing the actual value with the forecast
value, we adjust the parameters in the model. The process recurs until the
error meets the requirements.
Site Selection
Criteria for selecting a site
‡
The antenna height is greater than 20m
‡
The antenna is at least 5m taller than the nearest obstacle
5m
z
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Page29
If the antenna is taller than the nearest obstacle by 5m or more, the data in
GSM will be inherited, as defined according to the first Fresnel zone. This
condition is sufficiently compliant with the WCDMA requirements.
“Obstacle” here means the tallest building on the roof of the antenna. The
building serving as a site should be taller than the average height of the
surrounding buildings
Test Platform
z
Transmitting subsystems
‡
Transmitting antenna, feeder, high-frequency signal source, antenna
bracket
Antenna
OmniAntenna
bracket
Feeder
Transmitter
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Page30
After the test platform is set up, switch on the signal source to transmit the RF
signal, and begin drive test. To perform the CW test, it is necessary to select
an appropriate site for transmitting the RF signal. In case of CW test data
handling, it is necessary to be aware of the EIRP of the test BTS, and record
the data of signal gain attributable to each part, including signal source
transmitting power, RF cable loss, transmitting antenna gain, and receiving
antenna gain.
Test Platform
z
Receiving subsystem
‡
Test receiver, GPS receiver, test software, portable
GPS-Antenna
Antenna
Positioning Receiver
System
Data Acquisition System
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Page31
After the test platform is set up, switch on the signal source to transmit the RF
signal, and begin drive test. To perform the CW test, it is necessary to select
an appropriate site for transmitting the RF signal.In case of CW test data
handling, it is necessary to be aware of the EIRP of the test BTS, and record
the data of signal gain attributable to each part, including signal source
transmitting power, RF cable loss, transmitting antenna gain, and receiving
antenna gain.
Test Path
z
Rules of selecting a test path
‡
‡
‡
‡
‡
‡
Landform: the test path must consider all main landforms in the region.
Height: If the landform is very rugged, the test path must consider the
landforms of different heights in the region.
Distance: The test path must consider the positions differently away
from the site in the region.
Direction: The test points on the lengthways path must be identical
with that on the widthways path.
Length: The total length of the distance in one CW test should be
greater than 60km.
Number of test points: The more the test points are, the better
(>10000 points, >4 hours as a minimum)
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Page32
The distance corrected in the CW test primarily falls within the impact range
of this cell, so the test distance is not necessarily more than twice of the cell
radius. The total length of the test distance in a CW test should be greater than
60km.Generally, the number of test points for each site is more than 10000, or
the test duration is more than 4 hours. According to the sampling rate of 1
point/6m after smoothing the sampling data, it takes at least 60km as a test
distance for 10000 sampling points.
Test Path
z
Rules of selecting a test path
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Page33
Overlaying: The test path of different test sites can be preferably overlapped
to increase the reliability of the model
Obstacles: When the antenna signals are obstructed by one side of the building,
do not run to the shadow area behind this side of building
Drive Test
z
The sampling law is meets the Richard Law :40 wavelengths, 50
sampling points
z
Upper limit of drive speed: Vmax=0.8λ/Tsample
z
The test results obtained in exceptional circumstances must be
removed from the sampling data
z
‡
Sampling point with too high fading (more than 30dB) ;
‡
In a tunnel
‡
Under a viaduct
If using a directional antenna for CW test, the test path is selected
from the main lobe coverage area
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Page34
Sampling distance: The distance between adjacent sampling points should be
λ-λ/4 so as to eliminate the impact of Raylaigh fading. Suppose the
sampling frequency of the drive test equipment is: 1000HzThe 2G band bearer
wavelength is: 0.15m (50 sampling points are required per 6m)Upper limit of
drive speed: 0.8*0.15*1000=120m/s
Test Data Processing
z
The test data needs to be
processed before being able to be
identified by the planning software.
The processing procedure is:
‡
Data filtering
‡
Data dispersion
‡
Geographic averaging
‡
Format conversion
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Page35
The CW test data obtained after reasonable design are basis of our model
correction, and are input of the first step. The reasonableness of the CW test
data directly affects the correctness of the correction result. However, even the
design is reasonable, the measured data is not perfect, and needs further
processing. Typical processing steps include: Data filtering, data dispersion,
geographical averaging, and format conversion. In the actual test, some test
data may be inconsistent with the model correction requirements. In order to
avoid such data from affecting the model correction result adversely, such
data should be filtered. 1. Since we need to know the accurate position of each
test point in the model correction, for the data obtained from measuring the
places where GPS cannot position accurately should be filtered. Such
circumstances include: 1) under a viaduct; 2) in a tunnel; 3) in the narrow
street with tall buildings on both sides; 4) in the narrow street covered by
dense tree leaves. 2. Generally, we regard the distance 0.1R~2R away from
the antenna is reasonable, where R is the forecast cell radius. The signal
strength distribution and the propagation distance do not form a strict linear
relationship. If too near, the test data will be less, and average distribution will
be impossible. 3. If the receiving signal is too weak, exceptional value point
may occur, because the receiver is located at the critical status of resolving the
signal at this time, and its value is vulnerable to influence of transient
fluctuation. To prevent the deeply faded signals from being filtered, we use
the homocentric circle technology to filter out circular rings at the test point
lower than-121dbm, e.g., above 20% of the site ring. That is because the
receiver speed is far greater than the GPS signal collection speed, and will
result in multiple test data at one location point. Suppose the vehicle runs at
equal speeds, such data should be distributed to the two fixed points on
average, which is a process of data dispersion. The main function of
geographic averaging is to eliminate the influence of fast fading and slow
fading.
Contents
1. Radio Wave Introduction
2. Antenna
3. RF Basics
4. Symbol Explanation
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Page37
Positions and Functions of Antenna
BTS antenna & feeder system diagram
Antenna adjustment bracket
radio mast (φ50~114mm)
3-connector seal component
insulation sealing tape, PVC
insulation tape
GSM/CDMA
plate-shape
antenna
Grounding device
main
(7/8“)
feeder
Indoor super
flexible feeder
Outdoor
feeder
Cabling
rack
Feeder
clip
Lightning protection
device
Feeder cabling
window
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main device
of BTS
Page38
Positions and functions of antenna: In the radio communication system,
antenna is an interface between the transceiver and the outside communication
media. An antenna may both emit and receive radio waves; it converts the
high-frequency current to electromagnetic wave when transmitting; and
converts the electromagnetic wave to high-frequency current when receiving.
Other parts of the antenna & feeder are shown in the diagram.
Working Principles of Mobile Antenna
Dipole
Dipole
Feed network
Feed network
Feed network
Antenna
Connector
Directional antenna
Antenna
Connector
omni antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page39
The BTS antenna in mobile communication system is antenna array
consist of a lot of basic dipole units. The dipole unit is half wave dipole
that the length of dipole is half wave of electromagnetic wave. The feed
network usually use equal power network.
For directional antenna, there is a metal flat at the back of dipole units
as a reflection plane to increase the antenna gain.
The tie-in of antenna usually is DIN type (7/16''). Usually it is at the
bottom of antenna, sometimes at the back of antenna.
Structurally, the dipole units and feed network are covered by antenna
casing to protect the antenna. Usually, the antenna casing is made by
PVC material or tempered glass, and the loss for electromagnetic wave is
less and the strength is better.
Categories of Antenna
Categorize by emission direction
Directional antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
omni antenna
Page40
By emission direction, antennas are categorized into directional antenna and
omni antenna.
Directional antenna usually is used in urban area, and omni antenna is used in
rural area for wide coverage.
Categories of Antenna
Categorize by appearance
Plate-shape antenna
Cap-shape antenna
Whip-shape
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Paraboloid antenna
Page41
The installed antennas can be categorized into plate-shape antenna, cap-shape
antenna, whip-shape, and paraboloid antenna. As shown in the above diagram,
the cap-shape antenna is generally used in indoor distribution system, while
the paraboloid antenna is mainly used for satellite communication and radar.
Categories of Antenna
Categorize by polarization mode
Omni antenna
Uni-polarization
Directional antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Dual polarization
Directional antenna
Page42
By polarization mode, antennas are categorized into: vertical polarization
antenna (or unipolarization antenna), cross polarization antenna (or dual
polarization antenna). The foregoing two polarization modes are both line
polarization mode. Circle polarization and oval antenna are usually not used in
GSM. Unipolarization antennas are mostly vertical polarization antennas. The
polarization direction of their dipole unit is in the vertical direction. Dual
polarization antennas are mostly 45-degree slant polarization antennas. Their
dipole unit is a dipole that crosses the leftward tilt 45-degree polarization and
rightward tilt 45-degree polarization, as shown in the above diagram. The dual
polarization antennas are equivalent to two unipolarization antennas combined
into one. Use of dual polarization antennas can reduce the number of antennas
on the tower, and reduce the workload of installation, hence reduces the
system cost, so they are popularly applied now.
Categories of Antenna
Smart antenna
Smart directional antenna
Smart directional antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Smart omni-antenna
Page43
Smart antenna techniques are already used in many wireless systems, but
UMTS is the first system where they are considered already in the system
specification phase. Smart antennas are especially attractive in WCDMA
networks, as they could be used to reduce the intracell interference levels
considerably. Interference is one of the most important and difficult issues in
the WCDMA air interface, and any improvement in the interference level
management will bring increased capacity.
Generally, a smart antenna is an antenna structure consisting of more than one
physical antenna element, and a signal processing unit that controls these
elements and combines or distributes the signals among these elements. Note
that the antenna elements are not smart as such, but the smartness of the
device lies in the controlling signal processing unit.
Categories of Antenna
Electric down tilt Antenna
Electrical down tilt Antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
The main parts of electric down tilt antenna:
1. RCU (Remote Control Unit)
2. SBT (Smart Bias-Tee)
3. BT (Bias-Tee)
4. STMA (Smart TMA)
Page44
Electric Indices of Antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page45
Electric performances include: working band, gain, polarization mode, lobe
width, preset tilt angle, down tilt mode, down tilt angle adjustment range,
front and back suppression ratios, side lobe suppression ratio, zero point
filling, echo loss, power capacity, impedance, third order inter-modulation.
Antenna Direction Diagram
Symmetric halfhalf-wave dipole
side view
Top view
omni antenna direction diagram
directional antenna direction diagram
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Page46
Direction ability of antenna refers to the capability of the antenna emitting
electromagnetic waves toward a certain direction. For a receiving antenna, the
direction ability means the capability of the antenna receiving radio waves
from different directions. The characteristic curve of direction ability of
antenna is generally represented in a direction diagram.
Direction diagram is used for describing the capability of the antenna
receiving/emitting electromagnetic waves in different directions of the air.
Antenna Gain
2.15dB
dBi与dBd
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Page47
Gain means a ratio of the power density generated by the antenna at a certain
point in the maximum emission direction to the power density generated by
the ideal point source antenna at the same point. Gain reflects the capability of
the antenna emitting the radio waves in a certain direction in a centralized way.
Generally, the higher of the antenna gain is, the narrower the lobe width will
be, and more centralized the energy emitted by the antenna will be. The unit
of antenna gain is dBi or dBd. dBi uses the ideal point source antenna gain as
a reference, and dBd uses the half-wave dipole antenna gain as a reference.
The difference of values represented by the two kinds of unit is 2.15 dB. For
example, if the antenna gain is 11dBi, it can be said as 8.85dBd, as shown in
the above diagram. dBi is defined as the energy centralization capability of the
actual direction antenna (including omni antenna) relative to the isotropic
antenna, where “i” represents “Isotropic”.dBd is defined as the energy
centralization capability of the actual direction antenna (including omni
antenna) relative to the half-wave dipole antenna, where “d” represents
“Dipole”.
Antenna Pattern
Antenna pattern
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Page48
It is a three-dimensional solid pattern. It show the theoretic pattern of one
directional antenna.
Antenna Pattern
Side lobe
Zero point
Back
Main
lobe
filling
lobe
Max value
horizontal half-
Front to
power angles
back
Zero point
ratio
filling
Vertical pattern
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Horizontal pattern
Page49
Beam width is one of the key indices of antenna. It consists of horizontal halfpower angle and vertical half-power angle. Horizontal half-power
angle/vertical half-power angle is defined as beam width between the two
points where the power is reduced by half (3dB) in the horizontal/vertical
directional relative to the maximum emission direction. Typical horizontal
half-power angles of BTS antenna are 360°, 210°, 120°, 90°, 65°, 60°,
45° and 33°. Typical vertical half-power angles of BTS antenna are 6.5°,
13°, 25° and 78°. The front/back suppression ratio means the ratio of
signal emission strength of the antenna in the main lobe direction and in the
side lobe direction, and the difference between the side lobe level and the
maximum beam within backward 180°±30°. Generally, the front/back
ratio of antenna falls within 18~45dB. For dense urban areas, the antenna with
great front/back suppression ratio is preferred. Zero point filling: When the
BTS antenna vertical plane adopts the shaped-beam design, in order to make
the emission level in the service are more even, the first zero point of the
lower side lobe should be filled, rather than leaving an obvious zero depth.
High-gain antennas have narrow vertical half-power angles, so especially need
the zero point filling technology to improve the nearby coverage. Generally,
if the zero depth is -26dB greater than the main beam, it indicates that the
antenna has zero point filling. Some suppliers adopt percentage notation. For
example, when an antenna zero point filling is 10%. The relationship between
the
two notation methods is:
Y dB=20log(X%/100%)
For example, zero point filling 10%, namely, X=10; using dB to notate it:
Y=20log(10%/100%)=-20dBUpper side lobe suppression: For the cellular
system based on minor cell system, in order to improve the frequency
multiplexing and reduce the co-frequency interference between adjacent cells,
the BTS antenna lobe shaping should lower the side lobe aimed at the
interference area, and increase the D/U value. The first side lobe level should
be less than –18dB. For the BTS antenna based on major cell system, this
requirement is not imposed.
Mechanical Down Tilt and Electric Down Tilt
Mechanical down tilt
Electric down tilt
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Page51
Three kinds of methods and their combinations are usually used for antenna
beam downtilt: Mechanical downtilt, preset electricity downtilt and
electrically controlled downtilt (for electrically controlled antennas). During
adjustment of the electrically controlled antenna downtilt angle, the antenna
itself will not move, but the phase of the antenna dipole is adjusted through
electricity signals to change the field intensity so that the antenna emission
energy deviates from the zero-degree direction. The filed intensity of the
antenna is increased or decreased in each direction so that there will be little
change in the antenna pattern after the downtilt angle is changed. The
horizontal semi-power width is unrelated with the downtilt angle. However,
during mechanical adjustment of the downtilt angle, the antenna itself will be
moved. It is necessary to change the downtilt angle by adjusting the location
of the back support of the antenna. When the downtilt angle is very large,
although the coverage distance in the main lobe direction changes obviously,
yet signals in the direction perpendicular to the main lobe almost keep not
change, the antenna pattern deforms seriously, and the horizontal beam width
becomes greater as the downtilt angle is increased. A preset downtilt antenna
is similar to an electrically controlled antenna in working principle, but a
preset angle can not be adjusted.
The advantages of an electrically controlled antenna are as follows: When the
downtilt angle is very large, the coverage distance in the main lobe direction
will be shortened obviously and the antenna pattern will not remarkably
change, so the interference can be reduced. On the other hand, mechanical
downtilt may deform the pattern. The larger the angle is, the more serious the
deformation is. Hence it is difficult to control the interference.
In addition, electrically controlled downtilt and the mechanical downtilt have
different influence on the back lobe. Electrically controlled downtilt allows
further control of the influence on the back lobe, while mechanical downtilt
enlarges the influence on the back lobe.
If the mechanical downtilt angle is very large, the emission signals of the
antenna will propagate to high buildings in backward direction through the
back lobe, thus resulting in additional interference.
In addition, during network optimization, management and maintenance,
when we need to adjust the downtilt angle of an electrically controlled antenna,
it is unnecessary to shut down the entire system. So we can monitor the
adjustment of the antenna downtilt angle using special test equipment for
mobile communication, so as to ensure the optimum value of the downtilt
angle value of the antenna.
Contents
1. Radio Wave Introduction
2. Antenna
3. RF Basics
4. Symbol Explanation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page53
Introduction to Power Unit
z
Absolute power(dBm)
The absolute power of RF signals is notated by dBm and dBW.
Their conversion relationships with mW and W are: e.g., the signal
power is x W, its size notated by dBm is:
⎛ PW *1000 mw ⎞
p ( dBm ) = 10 lg⎜
⎟
1mw
⎝
⎠
For example, 1W=30dBm=0dBW.
z
⎛ P mw
p ( dB ) = 10 lg ⎜⎜ 1
⎝ P 2 mW
⎞
⎟⎟
⎠
Relative power(dB)
It is the logarithmic notation of the ratio of any two powers
For example:If P1 = 2w , P2 = 1w so P1 is 3dB greater than P2
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page54
Most spectrum analyzers use the dB notation to display the measurement
results. dB is so popularly used because it can use the logarithmic mode to
compress the signal level that changes in a wide range. For example, 1V
signal and 10uV signal can appear on the monitor whose dynamic range is
100dB, while the linear scale cannot display the two signals simultaneously in
a clear picture. Therefore, dB is determines the power ratio and voltage ratio
in the logarithmic mode. In this case, the multiplication operation changes to
convenient addition operation. It is typically used in calculating the gain and
loss in the electronic systems.
Noise-Related Concepts
z
Noise
‡
z
Noise means the unpredictable interference signal that occur during
the signal processing (the point frequency interference is not
counted as noise)
Noise figure
‡
Noise figure is used for measuring the processing capability of the
RF component for small signals, and is usually defined as: output
SNR divided by unit input SNR
Si
NF
Ni
So
No
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Page55
Typical noises are: external sky and electric noise, vehicle start-up noise, heat
noise from inside systems, scattered noise of transistor during operation,
intermodulation product of signal and noise.
Noise-Related Concepts
z
Noise figure formula of cascaded network
G1 NF1
NFtotal = NF 1 +
G2 NF2
Gn NFn
NF 2 − 1
NFn − 1
+ ... +
G1
G1 ⋅ G 2 ⋅ ... ⋅ Gn − 1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page56
As seen from the above formula, in the system noise, the noise figure of the
level-1 component imposes the greatest influence, the noise figure of level-2
component imposes less influence, and so on. This explains why the cascaded
noise figure is reduced after installing the tower amplifier. Usually, the NF of
TMA is 1.5 . The NF of the level-1 component of BTS is 2.2 .
Receiving Sensitivity
z
Receiving sensitivity
Expressed with power:
Smin=10log(KTB)+ Ft (NF) +(S/N), unit: dBm
K is a Boltzmann constant, unit: J/K (joule /K) , K=1.38066*10-19 J/K
T represents absolute temperature, unit: °K
B represents signal bandwidth, unit: Hz
Ft represents noise figure, unit: dB
(S/N) represents required signal-to-noise ratio, unit: dB
If B=1Hz, 10log(KTB)=-174dBm/Hz
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page57
Receiving sensitivity refers to the minimum receiving signal strength under a
certain signal-to-noise ratio. It is an index that reflects the receiving capability
of the equipment.
RF Components
z
Tower Mounted Amplifier
‡
Enlarge uplink signal, but it’s a loss
for downlink
z
Duplexer
‡
Sharing antenna for receiving and
transmitting
‡
Sharing antenna for multi-system
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page58
The core of a TMA is a low noise amplifier, which can be used to solve a limited
uplink coverage problem and increase the uplink coverage area. For uplink, the
gain is around 13dB. For downlink, the loss is around 0.3dB.
Duplexer : A device that permits the simultaneous use of a transmitter and a
receiver in connection with a common element such as an antenna system.
RF Components
z
Splitter
z
Coupler
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page59
Both couplers and power splitters are components for power distribution. The
difference is: a power splitter is for equal power distribution, while a coupler is
for non-equal power distribution. Therefore, couplers and power splitters are used
in different applications. In general, to distribute power to different antennas
within the same storey, a power splitter is used; to distribute power from the
trunk to tributaries of different stories, a coupler is used.
If couplers and power splitters are used in coordination, the transmit power of the
signal source can be distributed as evenly as possible to various antenna ports of
the system, namely, the transmit power of each antenna in the entire distribution
system is almost the same.
During power splitter selection, priority should be given to 1/2 power splitters,
not 1/4 power splitters. When using a 1/3 power splitter, make sure that the power
splitter is not too close to the antenna, and the feeder cable connecting them
should be over 20m long.
Distribution System
Splitter
Coupler
Splitter
Trunk
Trunk
Splitter
Trunk
Coupler
Splitter
Splitter
Tx/Rx
Splitter
Coupler
Splitter
Splitter
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page60
In the tunnel/subway/indoor, if we cover it just by outdoor NodeBs, because of
the blocking of the obstacle, the QoS will be very bad, even cause call drop. In
addition, in large building, we usually use micro cell system to cover it. But the
indoor environment is different with outdoor and it is hard to use one fixed
antenna to cover the whole building because of the blocking of the wall and other
obstacle. The indoor distribution system (IDS) can solve these problems and
increase the coverage of the micro NodeB. So the IDS is necessary in some
buildings.
In general, when selecting feeder cable types, select 7/8" cable for the trunk, and
1/2" common cables or super flexible cable for tributaries. During the trunk
cabling process, if the curvature radius does not meet the requirement, the trunk
can be disconnected at corners, and a section of 1/2" super flexible cable can be
used for cabling around the corners.
Contents
1. Radio Wave Introduction
2. Antenna
3. RF Basics
4. Symbol Explanation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page61
Symbol Explanation
z
Ec
‡
Average energy per Chip
‡
Not considered individually, but used for Ec/Io
‡
‡
Pilot Ec is measured by the UE (for HO) or the Pilot scanner, in
the form of Received Signal Code Power (RSCP)
For CPICH Ec:
„
„
‡
Depends on power and path loss.
Constant for a given power and path loss. Ec is not dependent on
load
For DPCH Ec:
„
Depends on power and path loss
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page62
The same could be said for the Dedicated Channel as for the pilot. The Ec
remains constant for a given power and path loss. The main difference
between the pilot and the DCH is that the DCH is power controlled.
Symbol Explanation
z
Eb
‡
‡
‡
Average energy per information bit for the PCCPCH, SCCPCH,
and DPCH, at the UE antenna connector.
Typically not considered individually, but used for Eb/Nt
Depends on channel power (can be variable), path loss, and
spreading gain (Gp)
‡
Constant for a given bit rate, channel power, and path loss
‡
Can be estimated form Ec and processing gain
„
Speech 12.2kbps example
„
Ec = -80 dBm
„
12.2kbps data rate => Processing gain = 24.98 dB
„
Eb~ -80 + 24.98 = -55.02 dBm
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page63
Symbol Explanation
z
Io
‡
‡
‡
The total received power spectral density, including signal and
interference, as measured at the UE antenna connector.
Similar to UTRA carrier Receive Strength Signal Indicator
(RSSI), at least for practical consideration (SC scanner)
„
RSSI in W or dBm
„
Io in W/Hz or dBm/Hz
Measured by the UE (for HO) or Pilot scanner in the form of
RSSI
‡
Depends on All channel power, All cells, and path loss
‡
Depends on same-cell and other cell loading
‡
Depends on external interferences
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page64
This is different form other Io definitions: other users’ interferences
Io = total receive power – per-channel receive power
This latest definition of Io is more in line with the ISCP (Interference Signal
Code Power) defined in the standard
Symbol Explanation
z
No common RF definition
‡
Thermal noise density
‡
Typically not considered individually, but used for Eb/No
‡
Can be calculated
„
No = KT
– K is the Bolzman constant, 1.38*10^-23
– T is the temperature, 290 K
„
‡
Typically the bandwidth noise and the receiver noise figure are
also considered
„
‡
No = 174 dBm/Hz under typical conditions
No = KTBNF, where NF is noise figure
To avoid confusion, NF should be used when referring to thermal
noise
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page65
For a WCDMA system, the bandwidth is 3.84Mcps. For WCDMA, the typical
noise figure is 3dB Uplink (NodeB, but Huawei’s NodeB is 2.2 dB in RND)
and 7 dB downlink (UE). These figures should always be checked against the
vendor specification, because implementation affects them
Based on the previous formula, this gives the total noise power (noise floor) as
Uplink: -174+66+3= -105dBm (RTWP value without subscriber)
Downlink: -174+66+7= -101dBm
These values are not the receiver sensitivity but the power measured at the
reference point, in the absence of signal. As WCDMA allows the extraction of
signals below the noise floor, the sensitivity can not be deducted from these
values.
Symbol Explanation
z
No for WCDMA system
‡
Total one-sided noise power spectral density due to all noise
sources
‡
Typically not considered individually, but used for Eb/No
‡
Defined this way, No and Io are substituted for one another:
„
On the uplink the substitution is valid
„
On the downlink, differentiating between Noise and Interference is
more challenging
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page66
Originally, Eb/No meant simply bit energy divided by noise spectral density.
However, over time the expression “Eb/No” has acquired an additional
meaning. One reason is the fact that in CDMA the interference spectral
density is added to the noise spectral density, since the interference is noise,
due, for example, to spreading. Thus, No can usually be replaced by Io,
interference plus noise density.
Symbol Explanation
z
z
RTWP
‡
Received Total Wide Bandwidth power
‡
To describe uplink interference level
‡
When uplink load increase 50%, RTWP value will increase 3dB
RSSI
‡
Received Signal Strength Indicator
‡
To describe downlink interference level at UE side
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page67
Symbol Explanation
z
z
RSCP
‡
Revived Signal Code Power (Ec)
‡
Ec/Io = RSCP/RSSI, to describe downlink CPICH quality
ISCP
‡
Interference Signal Code Power; can be estimated by:
„
ISCP = RSSI – RSCP
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page68
Thank you
www.huawei.com
WCDMA Radio
Network Coverage
Planning
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Objectives
z
Upon completion of this course, you will be able to:
‡
Know the contents and process of radio network planning
‡
Understand uplink budget and related parameters
‡
Understand downlink budget and related parameters
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page1
Contents
1. WCDMA Radio Network Planning Process
2. R99 Coverage Planning
3. HSDPA Coverage Planning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page2
Contents
1. WCDMA Radio Network Planning Process
2. R99 Coverage Planning
3. HSDPA Coverage Planning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page3
Capacity, Coverage, Quality
z
Capacity & Coverage
‡
↑ Users Æ ↑ Cell Load Æ ↑ Interference
Capacity
Level Æ ↓ Cell Coverage
‡
z
↑ Cell Coverage Æ Cell Load ↓ ÆCapacity ↓
COST
Capacity & Quality
‡
↑ Users Æ ↑ Cell Load Æ ↑ Interference
Quality
Coverage
Level Æ ↓ Quality
‡
z
↑ Quality ( BLERtar ↓ ) Æ ↓ Capacity
Coverage & Quality
‡
↑ Quality ( AMR ↑ ) Æ ↓ Cell Coverage
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page4
z
Capacity–coverage (typical case: downlink load balance)
z
Capacity–quality (typical case: lowering BLER through outer loop power control)
z
Coverage–quality (typical case: lowering the data rate of the connections with much
path loss through AMRC)
WCDMA Radio Network Planning
Process
z
Radio Network Planning (RNP) Process
‡
Step1 : Radio network dimensioning
‡
Step2 : Pre-planning of radio network
‡
Step3 : Cell planning of radio network
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page5
3G radio network planning can be divided into three phases. They are shown in
above figure, and consist of dimensioning, pre-planning and cell planning.
z
According to the above figure, the output result of radio network dimensioning stage
serves as the input condition of the pre-planning, and the pre-planning is based on
the network dimensioning and also checks the network dimensioning result. The site
quantity can be adjusted according to the pre-planning result in order to obtain the
reasonable sites. If the existing sites are considered in the selection of theoretical
sites during the pre-planning, the pre-planning result will be more practical, thus
facilitating the cell planning.
WCDMA Radio Network Planning
Process
z
Step1 : Radio network dimensioning
‡
Radio network dimensioning includes coverage
dimensioning and capacity dimensioning
‡
Obtain the scale of sites and configuration according to
input requirements when the coverage and capacity are
balanced
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page6
z
Radio Network Dimensioning is a simplified analysis for radio network
z
Dimensioning provides the first and most rapid evaluation of the network element
number as well as the associated capacity of those elements. The target of
dimensioning phase is to estimate the required site density and site configurations for
the area of interest. Dimensioning activities include radio link budget and coverage
analysis, capacity evaluation and final estimation of the amount of NodeB hardware
and E1, cell average throughput and cell edge throughput.
z
Objective:
‡
z
To obtain the network scale ( approximate NodeB number and configuration)
Method:
‡
Select a proper propagation model, traffic model and subscriber distribution,
and then estimate the NodeB number, coverage radius, E1 number per site,
cell throughput, cell edge throughput and so on.
WCDMA Radio Network Planning
Process
z
Input & output of radio network dimensioning
Input
Capacity Related
-Spectrum Available
-Subscriber Growth Forecast
-Traffic Density
Coverage Related
-Coverage Region
-Propagation Condition
-Area Type Information
QoS Related
9
Number of NodeB
9
Carrier configuration
9
CE configuration
9
Iub configuration
9
……
-Blocking Probability
-Indoor Coverage
-Coverage Probability
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page7
The service distribution, traffic density, traffic growth estimates and QoS requirements
are already essential elements in dimensioning phase. Quality is taken into account
here in terms of blocking and coverage probability.
WCDMA Radio Network Planning
Process
z
Step2 : Pre-planning of radio network – Initial Site Selection
‡
Based on RND, radio network pre-planning is intended to
determine:
„
Theoretical location of sites
„
Implementation parameters
„
Cell parameters
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page8
Wireless network dimensioning intends to obtain the approximate UTRAN scale.
Based on the network dimensioning, geography and traffic distribution, the network is
pre-planned in detail by using planning software and digital map.
z
Based on the network dimensioning and site information, the initially selected
WCDMA site is imported into the planning software, and coverage is estimated by
parameters setting. Then an analysis is made to check whether the coverage of the
system meet the requirements. If necessary, the height and tilt of the antenna and the
NodeB quantity are adjusted to optimize the coverage. And then the system capacity
is analyzed to check whether it meets the requirement.
z
Implementation parameters, such as antenna type / azimuth / tilt / altitude / feeder
type / length …
z
Cell parameters, such as transmission power of traffic channel and common channel,
orthogonal factor, primary scrambling code…
WCDMA Radio Network Planning
Process
z
Step2 : Pre-planning of radio network - Prediction
‡
Based on RND result, sites location, implementation
parameters and cell parameters, we should predict coverage
results such as best serving cell, pilot strength, overlapping
zone
‡
We should carry out detailed adjustment (such as NodeB
number, NodeB configuration, antenna parameters) after
analyzing the coverage prediction results
‡
Finally ,we obtain proper site location and parameters that
should satisfy coverage requirement
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page9
Based on the network dimensioning and site information, the initially selected
WCDMA BS is imported into the planning software, and coverage is estimated by
setting the cell parameters and engineering parameters. Then an analysis is made to
check whether the coverage of the system meet the requirements. Then the system
capacity is analyzed to check whether it meets the requirement. If necessary, the
height and tilt angle of the antenna and the BS quality are adjusted to optimize the
coverage.
WCDMA Radio Network Planning
Process
z
Step2 : Pre-planning of radio network - Prediction
Coverage by transmitter:
Display the best server
coverage
Coverage by signal level:
Display the signal level
across the studied area
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Overlapping zones:
Display the signal level
across the studied area
Page10
z
These graphs are prediction results of Huawei planning tool: U-Net
z
For the result of coverage prediction, focus on the distribution of best servers and pilot
level. For the small areas with unqualified level, adjust the azimuth and down tilt to
improve the coverage. For the large areas with weak coverage, analyze whether the
site distance is over large:
‡
If yes, add sites to improve coverage.
‡
If no, check whether the configuration of parameters related to coverage
prediction is correct.
WCDMA Radio Network Planning
Process
z
Step3 : Cell planning of radio network - Site Survey
‡
We have to select backup location for site if theoretical location
is not available
‡
Based on experience , backup site location is selected in
search ring scope , search ring =1/4×R
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page11
We should consider other factors when we select the backup sites
‡
Commercial factor: rent
‡
Radio propagation factor: situation / height / surrounding /
‡
Implementation factor: space / antenna installation / transmission / power
supply
WCDMA Radio Network Planning
Process
z
Step3 : Cell planning of radio network – Simulation
‡
U-Net use Monte Carlo simulation to generate user
distributions (snapshots)
‡
By iteration, U-Net get the UL/DL cell load, connection status
and rejected reason for each mobile
‡
The example of Monte Carlo simulation:
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page12
Simulation is oriented to simulate the running situation of networks under the current
network configuration so as to facilitate decision-making adjustment. Now there are
two system simulation classes: static simulation and dynamic simulation.
z
Static simulation focus on user behavior such as browsing Internet, call. It would gain
the performance of radio network based on “snapshot”.
z
Dynamic simulation focus on detail of user behavior such as duration and data rate of
browsing. It would gain the performance of radio network based on analysis of mobile
subscribers. But it requires higher precision of e-map.
z
At present, Static simulation is in common use. Monte Carlo simulation is one type of
static simulation.
WCDMA Radio Network Planning
Process
z
The following takes coverage probability for an example to
further understand how Monte Carlo simulation is performed
1st snapshot
3rd snapshot
2nd snapshot
Simulation
result
100%
20%
60%
100%
0%
75%
60%
40%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page13
WCDMA Radio Network Planning
Process
z
Step3 : Cell planning of radio network – Simulation
‡
Generate certain quantity of network instantaneous state (snapshot)
‡
Obtain connection performance between terminals and UTRAN by
incremental operation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page14
Some UEs or terminals are distributed based on a certain rule (such as random even
distribution) at each “snapshot”
z
It is required to consider the possibility of multiple connection failure (uplink/downlink
traffic channel maximum transmit power, unavailable channels, low Ec/Io and
uplink/downlink interference
WCDMA Radio Network Planning
Process
z
Step3 : Cell planning of radio network - Simulation
‡
Measure and analyze results of multiple “snapshots” to have a
overall understanding of network performance
Handover Status:
Display areas depending on the
probe mobile handover status
Pilot Quality (Ec/Io):
Displays the pilot quality across
the certain area
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Pilot Pollution:
Displays pilot pollution statistics
across the certain area
Page15
These graphs are prediction results (based on simulation) of Huawei planning tool: UNet
z
The previous predictions (Coverage by transmitter, Coverage by signal level,
Overlapping zones) are based on coverage, the predictions in this slide are based on
simulation.
Contents
1. WCDMA Radio Network Planning Process
2. R99 Coverage Planning
3. HSDPA Coverage Planning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page16
Contents
2. R99 Coverage Planning
2.1 Process of R99 Coverage Planning
2.2 R99 Uplink Budget
2.3 R99 Downlink Budget
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page17
Process of R99 Coverage Planning
z
Goal of R99 coverage planning
‡
obtain the cell radius
‡
estimate NodeB number that could satisfy coverage
requirement
Start
Link Budget
R
Path Loss
Propagation model
Cell Radius
NodeB Coverage Area
R
NodeB number
=
Total coverage area
NodeB coverage area
3
Area = * 3R 2
2
NodeB Number
End
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
9
Area = * 3R 2
8
Page18
In the coverage dimensioning, the link is estimated according to elements such as
planned area, network capacity, and equipment performance in order to obtain the
allowed maximum path loss. The maximum cell radius is obtained according to the
radio propagation model and allowed maximum path loss. And then the site coverage
area is calculated. Finally, the site quantity is calculated. Of course, the site quality is
only for the ideal cell status, and some additional sites will be needed in actual terrain
environment.
Contents
2. R99 Coverage Planning
2.1 Process of R99 Coverage Planning
2.2 R99 Uplink Budget
2.3 R99 Downlink Budget
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page19
Uplink Budget Principle
Antenna Gain
SHO Gain against Slow
fading
Pa
th
Lo
ss
Slow fading margin
SHO Gain against fast
fading
Fast fading margin
NodeB Antenna Gain
Body Loss
Interference margin
Cable Loss
UE Antenna Gain
Cable Loss
NodeB
Sensitivity
UE Transmit Power
Penetration
Loss
Penetration Loss
UPLINK BUDGET
Antenna Gain
SHO Gain
Maximum
Allowed path loss
Margin
Loss
NodeB reception sensitivity
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page20
Link dimensioning intends to estimate the system coverage by analyzing the factors
of the propagation channels of the uplink signal and downlink signal. It is the link
analysis model.
z
If the parameters such as transmit signal power, gain and loss of the transmitter and
receiver, and quality threshold of received signal are known or estimated, the allowed
maximum path loss used for ensuring the quality of received signal can be calculated.
Element of Uplink Budget
1. UE_TransmissionPower ( dBm )
‡
The UE maximum transmit power is determined by the power class
of the UE, which is specified by the 3GPP standard
‡
The Class 4 UE, with maximum power 21 dBm, are normally
considered due to their popularity in the market
Grade of UE power (TS 25.101 )
Power Class
Nominal maximum output power
Tolerance
1
+33dBm
+1/-3dB
2
+27dBm
+1/-3dB
3
+24dBm
+1/-3dB
4
+21dBm
+2/-2dB
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page21
In network planning, the value should be set according to the UE capacity with lowest
power grade in the commercial network of the operator.
z
Note that it is possible that a UE supporting high-speed uplink data service (higher
than 64kbps) has a higher power grade than a UE supporting only voice and lowspeed data services, for example, power grade 3dBm ~ 24dBm.
z
With a higher maximum power rating, the maximum path loss is increased accordingly. This
allows the operator to plan cells with a relatively larger coverage.
Ö
The UE cable loss, connector loss, and combiner loss are quite negligible, hence a 0
dB loss is assumed here。
Element of Uplink Budget
2. Body Loss ( dB )
‡
For voice, the body loss is 3 dB
‡
For the other service , the body loss is 0 dB
3. Gain of UE TX Antenna ( dBi )
‡
In general, the gain of UE antenna is 0 dBi
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page22
The 0 dBi antenna gain is considered here with respect to the internal antenna of
mobile phones.
Element of Uplink Budget
4. Penetration Loss ( dB )
‡
Indoor penetration loss means the difference between the
average signal strength outside the building and the average
signal strength of first floor of the building
‡
In terms of service coverage performance, micro-cells provide
an effective solution for achieving a high degree of indoor
penetration
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page23
The penetration loss is related to building type, incidence angle of the
radio wave and so on. In the link budget, assume that the penetration
loss obey the Log-Normal distribution. The penetration loss is related to
mean value of penetration loss and standard deviation
z
When indoor coverage is required to coverage by outdoor macro NodeBs, building
penetration loss needs to be considered. Building penetration loss is related to such
factors as incidence angle of the radio wave, the building construction (the
construction materials and number and size of windows), the internal building layout
and frequency. Building penetration loss is highly dependent on specific environment
and morphology and varies greatly. For instance, the wall thickness in Siberian tends
to be larger than that of Singapore in order to resist coldness and hence the former’s
building penetration loss is correspondingly larger.
z
In addition, sometimes vehicular coverage may be required and consequently
vehicular penetration loss also needs to be included in link budget process. typical
vehicular penetration loss is around 8dB.
Element of Uplink Budget
Sector Type
Gain of Antenna (dBi)
Omni
11
2 Sector
18
3 Sector
18
6 Sector
20
6. Cable loss ( dB )
- Cable loss between NodeB and antenna
Cable Loss
5. NodeB_AntennaGain ( dB )
- Jumper loss between NodeB and antenna
- Connectors loss between NodeB and antenna
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page24
z
Antenna gain: It refers to the ratio of the square of the actual field of an antenna at a
point in the space to the square of the field of an ideal radiation unit at the same point
in the space, namely power ratio. It is the gain in the main transmit direction. In
general, the gain is related to the antenna pattern. If the central lobe is narrow and the
back lobe and side lobe are small, the gain is high. If the transmit direction is
centralized, the antenna gain is high. For an omnidirectional antenna, the gain in all
the directions is the same.
z
Front-to-back ratio: It refers to the ratio of the maximum gain in the principal direction
to the gain in the reverse direction. It describes the directing feature. If it is high, the
directed receive performance of the antenna is high.
z
Beam width: It refers to the separation angle between the main transmit direction of
the power and the point with 3 dB of transmit power reduced, and the area is called
an antenna lobe. Tilt: It refers to the tilt angle of a directional plate antennal. It is used
to control interference and improve coverage.
z
Polarization: The vector direction of the electrical field in the direction with the highest
radiation. A dual polarized antenna can provide diversity over a single antenna, thus
saving one antenna.
z
In general, there are two or more lobes in an antenna pattern. The largest lobe is the
central lobe, and others are side lobes. The separation angle between the two halfpower points of the central lobe is the lobe width of the antenna pattern, namely, halfpower (angle) lobe width. If the central lobe is narrow, the directivity is high, and the
anti-interference capability is high.
Element of Uplink Budget
z
Path Loss and Fading
‡
Path Loss - fading due to propagation distance
‡
Long term (slow) fading - caused by shadowing
‡
Short term (fast) fading - caused by multi-path propagation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page25
Radio propagation in the land mobile channel is characterized by multiple reflections,
diffractions and attenuation of the signal energy. These are caused by natural
obstacles such as buildings, hills, and so on, resulting in so-called multi-path
propagation. Furthermore, with the moving of a mobile station, the signal amplitude,
delay and phase on various transmission paths vary with time and place. Therefore,
the levels of received signals are fluctuating and unstable and these multi-path
signals, if overlaid, will lead to fading i.e. short term fading. The mid-value field
strength of Rayleigh fading has relatively gentle change and is called “Slow fading”
i.e. long term fading. And it conforms to lognormal distribution.
z
Long term fading– the variation of signal level is slow and smooth.
z
Short term fading– the variation of signal level is fast and poignant
Element of Uplink Budget
7. Slow Fading Margin
‡
Slow Fading Margin depends on
„
Coverage Probability @ Cell Edge
The higher the coverage probability is, the more SFM is required
„
Standard Deviation of Slow Fading
Probability Density
The higher the standard deviation is, the more SFM is required
SFM required
Coverage
CoverageProbability
Probability@
@Cell
CellEdge:
Edge:
PPCOVERAGE (x)
= P [ F(x) > Fthreshold ]
COVERAGE (x) = P [ F(x) > Fthreshold ]
Without SFM
With SFM
Fthreshold
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Received Signal Level [dBm]
Page26
z
Slow Fading --- Signal levels obey Log-Normal distribution
z
Propagation models predict only mean values of signal strength , the mean value of signal
strength fluctuates. The deviation of the mean values has a nearly normal distribution in dB,
The variation in mean values is called log-normal fading.
z
Probability that the real signal strength will exceed the average one on the cell border is
around 50%,for higher than 50% coverage probability an additional margin has to be
introduced. The margin is called slow fading margin.
z
Slow Fading Margin (SFM) is related with coverage probability in cell edge and standard
deviation of slow fading. The equation is described as following:
z
The standard deviation is a measured value that is obtained from various clutter types. It
basically represents the variance (log-normally distributed around the mean value) of the
measured RF signal strengths at a certain distance from the site.
z
Therefore, the standard deviation would vary by clutter type. Depending on the propagation
environment, the log-normal standard deviation can easily vary between 6 and 8 dB or even
greater. Assuming flat terrain, rural or open clutter types would typically have lower standard
deviation levels than the suburban or urban clutter types. This is due to the highly obstructive
properties encountered in an urban environment that in turn will produce higher standard
deviation to mean signal strengths than that experienced in a rural area. Standard Deviation of
slow fading is related with morphology, frequency and environment. For instance:
Element of Uplink Budget
8. SHO Gain against Slow Fading
‡
SHO reduces slow fading margin compared to the single cell case
‡
SHO gain against slow fading can improve the coverage probability
SHO Gain against slow fading = SFM without SHO - SFM with SHO
SHO Gain Against SFM
(dB)
7
6
5
4
3
2
1
0
Standard deviation=11.7
Path loss slope=3.52
98%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
95%
92%
90%
85%
Area coverage probability
Page28
z
Soft Handover --- handover between different NodeBs
z
Softer Handover --- handover between cells in a NodeB
z
SHO gain over slow fading is also known as the Multi-Cell gain because in soft
handover more than 1 branch exists and hence the coverage probability increases
which would result in the decreasing of required slow fading margin.
z
Suppose that soft handover has 2 branches, and the orthogonality of the two radio
link branches on slow fading is 50%. We can calculate the slow fading margin
required with soft handovers based on the former assumptions, and compare it with
the slow fading margin required without soft handover to get the SHO gain over slow
fading.
z
SHO gain over slow fading is dependent on the required area coverage probability,
the propagation path loss slope and the STD. The following table gives the calculated
SHO gain over slow fading and the propagation path loss slope equals to 3.59.
Element of Uplink Budget
9. Fast Fading Margin
‡
Fast fading margin
„
required to guarantee fast power control
„
the factors affect FFM include channel model, service type, BLER
requirement
Fast Fading Margin= Eb/No without fast PC - Eb/No with fast PC
Uplink case: UE moves
towards the edge of the cell
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
z
Page29
Fast power control
‡
to enhance weak signal caused by Rayleigh fading
‡
to mitigate interference and enhance the capacity
‡
to promote power utilization efficiency
In WCDMA, user signals should be received at the NodeB with equal power all the
time and for downlink the transmitted TCH power should be as small as possible
while maintaining the required Qos. This implies that fast fading are compensated by
the power control algorithm, which requires additional headroom at both UE and
NodeB in order to let UE and NodeB following the power control commands at cell
edge.
Element of Uplink Budget
10. SHO Gain against Fast fading
‡
SHO gain against fast fading reduces the Eb/No requirement
‡
SHO gain against fast fading leads to a gain for reception
sensitivity
‡
SHO gain against fast fading exists for both uplink and
downlink (Typical value of SHO gain against FFM is 1.5dB)
SHO Gain Against Fast Fading = Eb/No without SHO – Eb/No with SHO
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page30
Because of the macro diversity combination, the soft handover reduces the required
Eb/No by a single radio link, which results in additional macro diversity gain.
Element of Uplink Budget
11. Interference Margin in Uplink
‡
Interference Margin is equal to Noise Rise
N oiseR ise = − 10 ⋅ L og 10 (1 − η U L )
[dB ]
Higher cell load leads to heavier interference
‡
Interference margin affects cell coverage
NoiseRise(dB)
‡
Interference Curve in Uplink
50% UL Load — 3dB
60% UL Load — 4dB
75% UL Load — 6dB
UL Load
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page31
Interference margin is the required margin in the link budget due to the noise rise
caused by system load (the noise rise due to other subscribers). The higher the
system load is, the larger the interference margin should be.
Element of Uplink Budget
12. NodeB Reception Sensitivity
Re ceptionSen sitivity = N th + NF + E b / N 0 − PG
‡
Nth : Thermal Noise
‡
NF: Noise Figure
‡
Eb/No : required Eb/No to maintain service quality
‡
PG: Processing Gain
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page32
Element of Uplink Budget
12. NodeB Reception Sensitivity
‡
Nth : Thermal Noise is the noise density generated by
environment and equals to:
N th = 10 log( K * T * W )
„
K:Boltzmann constant, 1.38×10-23J/K
„
T:Temperature in Kelvin, normal temperature: 290 K
„
W:Signal bandwidth, WCDMA signal bandwidth 3.84MHz
„
Nth = -108dBm/3.84MHz
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
If the W=1Hz, Nth=-174dBm/Hz
z
If the W=200kHz, Nth=-121dBm/200kHz
Page33
Element of Uplink Budget
12. NodeB Reception Sensitivity
‡
NF: Noise Figure :
„
For Huawei NodeB, latest NF is 1.6dB
„
For commercial UE, typical NF is 7dB.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page34
Typical noises are: external sky and electric noise, vehicle start-up noise, heat noise
from inside systems, scattered noise of transistor during operation, intermodulation
product of signal and noise.
z
Noise figure is used for measuring the processing capability of the RF component for
small signals, and is usually defined as: output SNR divided by unit input SNR.
Si
NF
Ni
So
No
Element of Uplink Budget
12. NodeB Reception Sensitivity
‡
PG: Processing Gain :
„
Processing gain is related with the service bearer rate, and the
detail formula is present below:
Pr ocess Gain = 10 log(
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
chip rate
)
bit rate
Page35
For common services, the bit rate of voice call is 12.2kbps, the bit rate of video phone
is 64kbps, and the highest packet service bit rate is 384kbps(R99). After the
spreading, the chip rate of different service all become 3.84Mcps.
Element of Uplink Budget
12. NodeB Reception Sensitivity
‡
Eb/No is required bit energy over the density of total noise to
maintain service quality
‡
Eb/No is obtained from link simulation
‡
Eb/No is related to following factors
„
Service type
„
Multi-path channel model
„
User speed
„
The target BLER
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page36
For instance:
Service
BLER
AMR12.2k
1.00%
CS64k
CS64k
0.10%
1.00%
Channel Model
Uplink Eb/N0
Downlink Eb/N0
TU3
5.4dB
7.8 dB
RA120
4.5 dB
8.3 dB
TU3
2.8 dB
6.3 dB
RA120
2.8 dB
6.8 dB
TU3
2.5 dB
5.4 dB
RA120
2.3 dB
6 dB
Contents
2. R99 Coverage Planning
2.1 Process of R99 Coverage Planning
2.2 R99 Uplink Budget
2.3 R99 Downlink Budget
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page37
Downlink Budget Principle
Antenna Gain
Pa
th
SHO Gain against Slow
fading
Slow fading margin
SHO Gain against fast
fading
Fast fading margin
Interference margin
Lo
ss
NodeB Antenna Gain
Body Loss
Cable Loss
UE Antenna Gain
NodeB Transmit Power
CableLoss
Penetration
Loss
UE
Sensitivity
Penetration Loss
DOWNLINK BUDGET
Antenna Gain
Maximum
allowed path loss
SHO Gain
Margin
Loss
UE reception sensitivity
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page38
Element of Downlink Budget
z
Interference Margin in Downlink
NoiseRise =
‡
I total PN + I own + I other No + (α + f )× PMax ⋅η DL / CL
=
=
PN
PN
PN
Wherein, α is non-orthogonality factor, f is the interference
ratio of other cell to own cell
‡
Interference margin is equal to noise rise
Interference Margin
IM(dB)
30.00
25.00
α =0.6, f
PMax=20W,
= 1.78,
η DL = 0.9
20.00
15.00
10.00
5.00
0.00
120
125
130
135
140
145
150
CL(dB)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page39
In case of multi-path propagation, certain energy will be detected by the RAKE
α
receiver, and become interference signals. We define the orthogonal factor
to describe this phenomenon. It is obtained through simulation, and related to
environment type and cell radius.
Case Study : R99 Uplink Budget
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page40
Case Study : R99 Downlink Budget
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page41
Contents
1. WCDMA Radio Network Planning Process
2. R99 Coverage Planning
3. HSDPA Coverage Planning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page42
Link Budget Difference of HSDPA and
R99
z
z
Coverage Requirement
‡
R99: Based on target continuous coverage service
‡
HSDPA: Based on cell edge throughput
Simulation KPI
‡
R99: Connect Success Rate, Coverage Probability, Pilot
Pollution Proportion and SHO
‡
HSDPA: Cell Average Throughput and Cell Edge Throughput
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page43
Continuous coverage target service requirement with specific coverage probability
should be given for R99
z
Cell edge throughput requirement with specific coverage requirement should be given
for HSDPA
Link Budget Difference of HSDPA and
R99
z
Target Network Load
‡
R99: DL target load should be set to 75%
‡
HSDPA: DL target load can be raised to 90%
HSDPA
power
Cell total power
Cell total power
90%
R99 DCH Power
R99 DCH Power
75%
CCH
CCH
More power
to ensure
R99
capacity
time
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
time
Page44
The cell total transmit power is the constant resources. The DL power consists of the
following three parts:
‡
Power of the HSPA DL physical channel (HS-PDSCH, and HS-SCCH)
‡
Common channel power
‡
DPCH power
Link Budget Difference of HSDPA and
R99
z
Other Parameters
‡
‡
R99:
„
Power control margin should be considered.
„
SHO gain should be considered.
HSDPA:
„
Power control margin need not be considered.
„
SHO gain should not be considered for HSDPA.
„
Other elements: Number of HS-PDSCH, HSDPA power, etc.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page45
Fast power control
‡
For R99, power control margin should be considered
‡
For HSDPA, the maximum transmission power for HS-PDSCH is the
remaining power excluding R99 power and power margin, and no power
control margin
z
z
SHO gain
‡
For R99, SHO gain should be considered
‡
For HSDPA, only hard handover, no SHO gain
HSDPA related parameters should be configured when simulation
‡
Max number of HS-PDSCH channel
‡
Min number of HS-PDSCH channel
‡
HSDPA power allocation, dynamic or fixed
‡
HS-SCCH power allocation, dynamic or fixed
‡
Max number of HSDPA users
‡
Scheduling Algorithm
HSDPA Deployment Strategy
Mature Phase
Focus on:
HSDPA+R99
f2
HSDPA+R99
R99+HSDPA
f1
R99+HSDP
A
R99+HSDPA
HSDPA+R99
f2
R99
f1
R99+HSDPA
R99
Urban
Suburban & Rural
„ HSDPA Performance
Initial Phase
Focus on:
„ HSDPA coverage
„ no impact on R99
Hot Spot & Dense
Urban
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page46
Single carrier for HSDPA and R99
‡
Advantages
„
Maximum resource utilization efficiency
Save cost
Disadvantages
„
‡
z
z
Handover between HSDPA cell and R99 cell
Two carriers for HSDPA and R99
‡
Advantages
‡
Fewer inter-frequency handover for HSDPA user
Disadvantages
„
„
High cost
HSDPA Link Budget Categories
HSDPA+R99
„ HSDPA Throughput Requirement
„ Guarantee R99 CS Traffic Capacity
R9
9
„ Not Change R99 Coverage
R99 requirement should be met first, and then HSDPA throughput !
„ HSDPA Throughput Requirement
No WCDMA
HSDPA+R9
9
„ R99/R4 Capacity, Coverage Requirement
R99 and HSDPA requirement should be met simultaneously !
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page47
If operator wants to upgrade HSDPA from R99, R99 should be met first, and HSDPA
should not affect the R99.
z
If operator setup R99 and HSDPA directly, R99 and HSDPA requirement should be
met at the same time.
HSDPA Link Budget Element
z
DL Coupling Loss
DL _ CouplingLo ss = PL _ DL + Lf _ BS − Ga _ antenna + Lb + SFM NSHO + Lp
z
Cell edge Ec/No
Ec
= 10 × log(
No
PHS − DSCH
(α + f )× η DL × Pmax
+ 10
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
z
DL _ CoupleLoss + NF + Nt
10
Page48
DL Coupling Loss :
‡
PL_DL: Downlink path loss
‡
Lf_BS: cable loss of NodeB
‡
Ga_antenna: Gain of UE antenna and NodeB antenna
‡
Lb: Body loss
‡
SFMNSHO: Slow fading margin without soft handover
‡
Lp: Penetration loss
Cell edge Ec/No:
‡
PHS-DSCH : total power of HS-DSCH channel
‡
α : non-orthogonality factor
‡
f : neighbor cell interference factor
‡
η DL : downlink load factor including R99 and HSDPA service
‡
Pmax : max transmission power of downlink
‡
Nt : thermal noise power spectral density , typical value is -108.16dB
‡
NF : receiver noise figure of UE, typical value is 7dB
)
HSDPA Link Budget Principle
z
Goal of HSDPA link budget
‡
The HSDPA link budget is usually based on the R99 link budget to get
the cell edge throughput in downlink
‡
The HSDPA cell edge throughput need to be calculate depend on
simulation results, which is related with cell edge Ec/No
z
Simulation
Conditions
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
‡
Channel model-TU3
‡
5 codes
Page49
z
The theoretical maximum throughput is decided by the number of HSDPA codes.
z
For HSDPA , soft handover gain and fast fading margin should not be considered in
link budget , since neither power control nor soft handover in HS-PDSCH channel
HSDPA Link Budget Principle
z
According to R99 Cell Radius and HSDPA Power Allocation,
calculate Cell Edge Throughput
R99 Network Cell Radius
Downlink Path Loss
DL_CoupleLoss=DL_PL+TxBodyLoss+TxCableLoss-TxAntennaGain+RxBodyLoss+
RxCableLoss-RxAntennaGain+PenetrationLoss+SlowFadingMargin
Downlink Coupling Loss
Ec/No at Cell Edge
HSDPA power
Ec
= 10 × log(
No
PHS − DSCH
(α + f )×η DL × Pmax + 10
DL _ CoupleLoss+NF+Nt
10
Simulation Results
Cell Edge Throughput
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page50
The step is present below:
‡
According to the Cell Radius comes from R99 dimensioning, the Downlink
Path Loss can be calculated
‡
According to the Downlink Path Loss , the Downlink Coupling Loss can be
calculated
‡
According to the Downlink Coupling Loss and HS-DSCH Power, Cell Edge
Ec/No can be calculated
‡
According to the Cell Edge Ec/No and simulation result, Cell Edge Throughput
can be calculated
)
HSDPA Link Budget Principle
z
According to Cell Edge Throughput requirement and HSDPA
Power Allocation, calculate HSDPA Cell Radius
Cell Edge Throughput
Simulation results
Ec/No at Cell Edge
HSDPA power
Downlink Coupling Loss
PHS − DSCH
− (α + f )×η DL × Pmax
Ec
No
DL _ CoupleLoss =
NF+Nt
Downlink Path Loss
DL_CoupleLoss=DL_PL+TxBodyLoss+TxCableLoss-TxAntennaGain+RxBodyLoss+
RxCableLoss-RxAntennaGain+PenetrationLoss+SlowFadingMargin
HSDPA Cell Radius
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page51
The step is present below:
‡
According to the Cell Edge Throughput and simulation result, Cell Edge Ec/No
can be calculated
‡
According to the Cell Edge Ec/No and HS-DSCH Power, the Downlink
Coupling Loss can be calculated
‡
According to the Downlink Coupling Loss, the Downlink Path Loss can be
calculated
‡
According to the Downlink Path Loss and and Propagation Model, HSDPA
Cell radius can be calculated
HSDPA Link Budget Principle
z
According to Cell Edge Throughput requirement and Cell
Radius, calculate HSDPA Power
Cell Radius
Cell Edge Throughput
Simulation results
Ec/No at Cell Edge
Downlink Path Loss
Downlink Coupling Loss
PHSDPA = PHS − DSCH + PHS − SCCH
=
( DL _ CoupleLoss × Nt × NF + (α + f ) ×η DL × Pmax ) ×
Pmax
Ec
No + P
HS − SCCH
HSDPA Power
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page52
The step is present below:
‡
According to the Cell Radius comes from R99 dimensioning, the Downlink
Path Loss can be calculated
‡
According to the Downlink Path Loss , the Downlink Coupling Loss can be
calculated
‡
According to the Cell Edge Throughput and simulation result, Cell Edge Ec/No
can be calculated
‡
According to the Downlink Coupling Loss and Cell Edge Ec/No , HS-DSCH
Power can be calculated
Case Study – HSDPA Link Budget
z
Assumption:
‡
Downlink maximum path loss: 129.06 dB
‡
Cable loss : 0.5 dB
‡
NodeB antenna gain : 18dBi
‡
Penetration loss : 20dB ( required in indoor coverage )
‡
Body loss : 0 dB
‡
Slow fading margin without soft handover gain against SFM :
13.1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page53
Case Study – HSDPA Link Budget
z
Assumption:
‡
Channel type: TU3
‡
Non-orthogonality factor: 0.5
‡
Adjacent cell interference factor: 1.78
‡
HSDPA code resource: 5
‡
Cell radius: 0.36 km
‡
UE Category: 8
‡
Max transmitter power of downlink: 20000 mW
‡
Total power of HSDPA: 6000 mW (30% downlink power allocation)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page54
Case Study – HSDPA Link Budget
z
According to the assumption above, the DL Coupling Loss for
HSDPA is calculated below:
DL _ CouplingLo ss = PL _ DL + Lf _ BS − Ga _ antenna + Lb + SFM NSHO + Lp
= 129.06 + 0.5 - 18 + 0 + 13.1 + 20 = 144.66dB
z
Cell Edge Ec/No will be carry out base on equation below:
Ec
= 10 * log(
No
= 10 * log(
PHS − DSCH
(α
+ f )× η DL × Pmax + 10
DL _ CoupleLoss + NF + Nt
10
6000
( 0 . 5 + 1 . 78 ) * 0 . 9 * 20000 + 10
z
144 . 66 −108 . 16 + 7
10
)
) = − 10 . 2 dB
Base on the simulation result, the Cell Edge Throughput for
HSDPA can be obtained is 173.80 Kbps
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page55
Thank you
www.huawei.com
WCDMA Radio
Network Capacity
Planning
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Foreword
z
WCDMA is a self-interference system
z
WCDMA system capacity is closely related to coverage
z
WCDMA network capacity has the “soft capacity” feature
z
The WCDMA network capacity restriction factors in the radio
network part include the following:
‡
Uplink interference
‡
Downlink power
‡
Downlink channel code resources (OVSF)
‡
Channel element (CE)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page1
Objectives
z
Upon completion of this course, you will be able to:
‡
‡
‡
‡
Grasp the parameters of 3G traffic model
Understand the factors that restrict the WCDMA network
capacity
Understand the methods and procedures of estimating multiservice capacity
Understand the key technologies for enhancing network
capacity
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page2
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page3
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page4
Contents
1. Traffic Model
1.1 Overview of traffic model
1.2 CS traffic model
1.3 PS traffic model
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page5
QoS Type
Real-time category
It is necessary to maintain the time relationship
Voice service,
Conversation
between the information entities in the stream.
videophone
al
Small time delay tolerance, requiring data rate
symmetry
Streaming
Non real-time category
Interactive
Background
Typically unidirectional services, high
Streaming
requirements on error tolerance, high
multimedia
requirements on data rate
Request-response mode, data integrity must be
Web page
maintained. High requirements on error tolerance, browse,
low requirements on time delay tolerance
network game
Data integrity should be maintained. Small delay
Background
restriction, requiring correct transmission
download of
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Email
Page6
z
For the session-type service, requirement on end-to-end delay is strict. For example, for the
voice service, the delay is required to be smaller than 150ms, and must not exceed 400ms,
otherwise, it will be difficult to understand the voice. The session-type services are typically
carried by the CS domain. For the session-type services, the system can perform no queue
processing for the calls. In this case, we can use the Erlang B formula or the extended Erlang
B formula to calculate.
z
Compared with the session-type service, the stream-type service imposes low requirement on
the end-to-end delay. Generally, the stream-type service tolerates the call waiting to a greater
extent, and can provide the call queue mechanism. In this case, we can use the Erlang C
formula to calculate the blocking probability of this type of users (defined as the probability of
the call waiting for a specified time).
z
Interaction-type service refers to the service through which the user requests data from the
server. The service is described with the terminal user’s request response pattern. Therefore,
round-trip delay is the most important index of this service type. The interaction-type services
are typically carried on the CS domain. The background-service tolerates delay to the greatest
extent, and can tolerate the delay of a magnitude of an hour. Due to such great delay tolerance,
the system can save such requests in the busy hour, and respond when the channel becomes
idle; meanwhile, for such services, once a request with higher QoS comes in, the processing
can be stopped at any time. The system decides startup and termination at any time, the
above formulas—Erlang B formula and Erlang C formula are not applicable. Generally,
according to the difference between the maximum number of channels and the busy-hour
average occupied channels, we can calculate the traffic of the background-type service. The
users of traffic-type services also tolerate the call waiting to some extent. The system provides
a queue mechanism, and uses the Erlang C formula to calculate the blocking rate.
Traffic Model
Service Pattern
Traffic Model
Results
User Behaviour
System Configuration
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page7
By determining the service pattern and the user behaviour parameters, we determine
the traffic models of various services in the network. By calculating the hybrid services
of multiple traffic models, we determine the network system configuration.
The Contents of Traffic Model
z
Service pattern refers to the service features
z
User behaviour refers to the conduct of people in using the
service
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page8
Service pattern is a means of researching the capacity features of each service type
and the QoS expected by the users who are using the service from perspective of
data transmission. In the actual application, service pattern is closely related to, and
sometimes is no strictly different from, the traffic measurement model.
z
In the data application, the user behaviour research mainly forecasts the service
types available from the 3G, the number of users of each service type, frequency of
using the service, and the distribution of users in different regions
Typical Service Features
Description
z
Typical service features include the following feature
parameters:
‡
User type (indoor ,outdoor, vehicle)
‡
User’s average moving speed
‡
Service Type
‡
Uplink and downlink service rates
‡
Spreading factor
‡
Time delay requirements of the service
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page9
For each service, since the channel structure and demodulation method are different,
the required uplink rate is different from the required downlink rate even for the same
service type and the same data rate. For a typical service, we first need to identify
whether it is uplink or downlink rate. A typical service can be described by the
following parameters:
z
‡
User type (indoor users, users inside a vehicle, outdoor users)
‡
User’s average moving speed (km/h)
‡
Voice, real-time data, non real time data
‡
Uplink and downlink service rates (kbps)
‡
Spread factor (SF)
‡
Signal delay requirement of the service (ms).
The above parameters ultimately determine the QoS requirements of the service.
Contents
1. Traffic Model
1.1 Overview of traffic model
1.2 CS traffic model
1.3 PS traffic model
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page10
CS Traffic Model
z
Voice service is a typical CS services. Voice data arrival conforms
to the Poisson distribution. Its time interval conforms to the
exponent distribution
z
Key parameters of the model
‡
Penetration rate
‡
BHCA: busy-hour call attempts
‡
Mean call duration (s)
‡
Activity factor
‡
Mean rate of service (kbps)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page11
Penetration rate: The percentage of the users that activates this service to all the
users registered in the network.
z
Activity Factor: The weight of the time of service full-rate transmission among the
duration of a single session.
CS Traffic Model Parameters
z
Mean busy-hour traffic (Erlang) per user = BHCA × mean call
duration /3600
z
Mean busy hour traffic volume per user (kbit) = BHCA × mean call
duration × activity factor × mean rate
z
Mean busy hour throughput per user (bps) = mean busy hour
traffic volume per user × 1000/3600
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page12
(Erl) For CS service, mean busy-hour traffic (Erlang) per user = BHCA * mean call
duration /3600 (Erl)
z
(kbps) Mean busy-hour throughput per user = BHCA * mean call duration * activity
factor * mean rate of service*1000/3600 (kbps)
Contents
1. Traffic Model
1.1 Overview of traffic model
1.2 CS traffic model
1.3 PS traffic model
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page13
PS Traffic Model
Session
Packet Call
Packet Call
Downloading
Active
Downloading
Dormant
Dormant
Active
Packet Call
Data Burst
Data Burst
Data Burst
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page14
The most frequently used model is the packet service session process model
described in ETSI UMTS30.03.
PS Traffic Model Parameters
Packet Call Num/Session
Packet Num/Packet Call
Traffic Model
Packet Size (bytes)
Reading Time (sec)
Typical Bear Rate (kbps)
BLER
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page15
The service pattern-related parameters in the traffic model include: these parameters
commonly determine the pattern of one session.
z
z
We identify the service types through the different values of the parameters.
‡
Packet Call Num/Session: Takes on the geometric random distribution
‡
Reading Time (sec): Takes on the geographic random distribution
‡
Packet Num/Packet Call: Takes on the geographic random distribution
‡
Packet size: Takes on the Pareto random distribution
When using the parameters, the average values will apply.
Parameter Determining
z
The basic parameters in the traffic model are determined in
the following ways:
‡
Obtain numerous basic parameter sample data from the
existing network
‡
Obtain the probability distribution of the parameters through
processing of the sample data
‡
Take the distribution most proximate to the standard probability
as the corresponding parameter distribution through
comparison with the standard distribution function
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page16
We have determined the traffic model parameters. The linchpin is to determine such
parameter values. The parameter value varies between different services. Pareto
General standard probability distributions include: logarithmic normal distribution,
Pareto distribution, geometrical distribution, and negative exponent distribution.
PS User Behaviour Parameters
Penetration Rate
BHSA
User Behaviour
User Distribution
(High, Medium, Low end)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page17
The country, region, life custom and economic level will affect the service distribution.
In the planning, we divide the users into high-end users, mid-end users and low-end
users, and believe that the BHSA and penetration rate are different between different
types of user groups. Currently, we can only use the existing analysis to make
prediction. In the future, the progress of the construction of the WCDMA pilot system
will provide us with reference.
PS User Behaviour Parameters
z
Penetration Rate
z
BHSA
‡
z
The times of single-user busy hour sessions of this service
User Distribution (High, Medium, Low end)
‡
The users are divided into high-end, mid-end and low-end
users.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page18
Penetration Rate: The percentage of the users that activate this service to all the
users registered in the network. It varies between different service types, user types,
and operators. More importantly, it is related to the penetration rate and time. With the
elapse of time, the penetration rate will increase gradually.
z
BHSA: Times of the single-user busy hour sessions of the service. It varies between
service types and user types.
z
User Distribution (High, Medium, Low end): The users are divided into high-end,
mid-end and low-end users according to the ARPU. Different operators and different
application situations will have different user distributions.
PS Traffic Model Parameters
z
Data Transmission time (s): The time in a single session of
service for purpose of transmitting data.
DataTransm issionTime =
z
Holding Time (s): Average duration of a single session of service
HoldingTim e = (
z
SessionTra fficVolume × 8 / 1000
1
×
1 − BLER
TypicalRat e
PackketCal lNum
− 1 ) × Re adingTime + DataTransm issionTime
Session
Activity Factor:
ActivityFactor =
DataTransm issionTime
HoldingTim e
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page19
In the PS service, when calculating the data transmission time, the retransmission
caused by erroneous blocks should be considered. Suppose the data volume of
service source is N, the air interface block error rate is BLER, the total required data
volume to be transmitted via the air interface is
N + N * BLER + N * BLER 2 + N * BLER 3 + Λ Λ + N * BLER n =
1
*N
1 − BLER
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page20
Basic Principles
z
In the WCDMA system, all the cells use the same frequency,
which is conducive to improving the WCDMA system
capacity. However, for reason of co-frequency multiplexing,
the system incurs interference between users. This multiaccess interference restricts the capacity in turn.
z
The radio system capacity is decided by uplink and
downlink. When planning the capacity, we must analyze
from both uplink and downlink perspectives.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page21
Interference is the main factor that decides the system performance of the cellular
system. The interference in a cellular system consists of two parts: co-frequency and
adjacent frequency interference. All users in the WCDMA system use the same band.
All the users are different by modulating the respective signal to the code sequences
that are mutually orthogonal. Therefore, the receiving signal is the sum of all user
signals and the channel noise.
Contents
2. Interference Analysis
2.1 Uplink Interference Analysis
2.2 Downlink Interference Analysis
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page22
Uplink Interference Analysis
z
Uplink interference analysis is based on the following
formula:
I TOT = I own + I other + PN
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Where:
‡
‡
‡
‡
I TOT
I own
: Total interference received by NodeB
: Interference from the users of this cell
I other : Interference from the users of adjacent cells
PN
: Noise floor of the receiver
Page23
Uplink Interference Analysis
z
Receiver noise floor: PN
PN = 10 log( K * T * W ) + NF
‡
For Huawei NodeB, the typical value is -106.4dBm/3.84MHZ
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
K: Boltzmann constant, 1.38×10-23J/K
z
T: Temperature in Kelvin, normal temperature: 290 K
z
W: Signal bandwidth, WCDMA signal bandwidth 3.84MHz
z
Nth = 10log(K*T*W)=-108dBm/3.84MHz
z
NF: For Huawei NodeB, typical value is 1.6dB.
Page24
Uplink Interference Analysis
z
I own : Interference from users of this cell
‡
‡
Interference that every user must overcome is : I total − P j
Pj is the receiving power of the user j ,ρ j
( Eb / No ) Avg
‡
‡
Under the ideal power control 10
:
Hence:
Pj =
I TOT
1+
( Eb
10
‡
10
1
/ No
) Avg
_ j
⋅
10
is UL activity factor
_ j
=
Pj
I TOT − P j
⋅
W 1
⋅
Rj ρ j
1
W
⋅
Rj ρj
The interference from users of this cell is the sum of power of
all the users arriving at the receiver:
I own =
N
∑
Pj
1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page25
Activity Factor: The weight of the time of service full-rate transmission among the
duration of a single session. Which is defined by the following formula:
ActiveFactor =
DataTransm issionTime
HoldingTim e
Uplink Interference Analysis
z
I other :Interference from users of adjacent cell
‡
The interference from users of adjacent cell is difficult to
analyze theoretically, because it is related to user distribution,
cell layout, and antenna direction diagram.
‡
Adjacent cell interference factor :
f =
I other
I own
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page26
When the users are distributed evenly
‡
For omni cell, the typical value of adjacent cell interference factor is 0.55
‡
For the 3-sector directional cell, the typical value of adjacent cell interference
factor is 0.65
Uplink Interference Analysis
I TOT = I own + I other + PN = (1 + f
N
)∑
1
I TOT
1
1+
( Eb / No ) Avg _ j
10
10
Define:
Lj =
1
1
1+
( Eb / No ) Avg _ j
10
10
⋅
W 1
⋅
Rj ρ j
N
Then:
I TOT = I TOT ⋅ (1 + f ) ⋅ ∑ L j + PN
1
Obtain:
I TOT = PN ⋅
1
N
1 − (1 + f ) ⋅ ∑ L j
1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Where:
‡
W 1
⋅
⋅
Rj ρ j
N is the number of users in the cell.
Page27
+ PN
Uplink Interference Analysis
z
Suppose that:
‡
All the users are 12.2 kbps voice users, Eb/NoAvg = 5dB
‡
Voice activity factorρ j = 0.67
‡
Adjacent cell interference factor f=0.55
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page28
Under the above assumption, the threshold capacity is approx 96 users.
Uplink Interference Analysis
z
According to the above mentioned relationship, the noise will rise:
I
1
1
=
NoiseRise = TOT =
N
PN
1 −ηUL
1 − (1 + f )∑ L j
1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page29
z
The NoiseRise is used in link budget to estimate the Interference Margin
z
If uplink cell load is 50%, NoiseRise will be 3dB
z
If uplink cell load is 60%, NoiseRise will be 4dB
z
If uplink cell load is 75%, NoiseRise will be 6dB
Uplink Interference Analysis
z
Define the uplink load factor for one user:
η j = (1 + f )× L j = (1 + f )×
1
1
1+
( EbvsNo) Avg _ j
10
z
10
W 1
⋅
Rj ρ j
Define the uplink load factor for the cell:
N
N
1
1
ηUL = (1 + f )× ∑ L j = (1 + f )× ∑
1
1
1+
( EbvsNo)Avg _ j
10
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
⋅
10
⋅
W 1
⋅
Rj ρ j
Page30
When the uplink load factor is 1, I TOT is infinite, and the corresponding capacity is
called “threshold capacity”.
Uplink Interference Analysis Limitation
z
The above mentioned theoretic analysis uses the following
simplifying explicitly or implicitly:
‡
No consideration of the influence of soft handover
‡
No consideration of the influence of AMRC and hybrid service
‡
Ideal power control assumption
‡
z
Assume that the users are distributed evenly, and the adjacent cell
interference is constant
Considering the above factors, the system simulation is a more
accurate method:
‡
Static simulation: Monte_Carlo method
‡
Dynamic simulation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page31
No consideration of the influence of soft handover
‡
The users in the soft handover state generates the interference which is
slightly less than that generated by ordinary users.
z
No consideration of the influence of AMRC and hybrid service
‡
AMRC reduces the voice service rate of some users, and makes them
generate less interference, and make the system support more users. (But call
quality of such users will be deteriorated)
‡
Different services have different data rates and demodulation thresholds. So,
we should use the previous methods for analysis, but it will complicate the
calculation process.
‡
Since the time-variable feature of the mobile transmission environment, the
demodulation threshold even for the same service is time-variable.
z
Ideal power control assumption
‡
The power control commands of the actual system have certain error codes so
that the power control process is not ideal, and reduces the system capacity
z
Assume that the users are distributed evenly, and the adjacent cell interference is
constant
Contents
2. Interference Analysis
2.1 Uplink Interference Analysis
2.2 Downlink Interference Analysis
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page32
Downlink Interference Analysis
z
Downlink interference analysis is based on the following
formula:
I TOT = I own + I other + PN
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page33
Where:
‡
‡
‡
‡
I TOT
I own
: Total interference received by UE
: Interference from downlink signal of this cell
I other : Interference from downlink signal of adjacent cells
PN
: Noise floor of the receiver
Downlink Interference Analysis
z
Receiver noise floor: PN
PN = 10 log( K * T * W ) + NF
‡
For commercial UE, the typical value is -101dBm/3.84MHZ
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
K: Boltzmann constant, 1.38×10-23J/K
z
T: Temperature in Kelvin, normal temperature: 290 K
z
W: Signal bandwidth, WCDMA signal bandwidth 3.84MHz
z
Nth = 10log(K*T*W)=-108dBm/3.84MHz
z
NF: For commercial UE, typical value is 7dB.
Page34
Downlink Interference Analysis
z
I own :Interference from downlink signal of this cell
‡
The downlink users are identified with the mutually orthogonal
OVSF codes. In the static propagation conditions without multipath, no mutual interference exists.
‡
In case of multi-path propagation, certain energy will be
detected by the RAKE receiver, and become interference
α
signals. We define the non-orthogonal
factor
phenomenon:
( Iown) j = α × PTX
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
to describe this
Page35
α
Compared to the uplink load equation, the most important new parameter is
,
which represents the non-orthogonality factor in the downlink. WCDMA employs
orthogonal codes in the downlink to separate users, and without any multi-path
propagation the orthogonality remains when the base station signal is received by the
mobile. However, if there is sufficient delay spread in the radio channel, the mobile
will see part of the base station signal as multiple access interference. The
orthogonality of 1 corresponds to perfectly orthogonal users. Typically, the nonorthogonality is between 0.1 and 0.6 in multi-path channels.
z
Where:
‡
PTX is the actual transmission power of NodeB
Downlink Interference Analysis
z
I other : Interference from the downlink signal of adjacent cell
‡
The transmitting signal of the adjacent cell NodeB will cause
interference to the users in the current cell. Since the
scrambling codes of users are different, such interference is
non-orthogonal
‡
Hence we obtain:
( Iother ) j = f × PTX
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Where:
‡
f
‡
PTX is the actual transmission power of NodeB
is Adjacent cell interference factor
Page36
Downlink Interference Analysis
z
Ec/Io for User j is:
Pj
(
Pj
Ec
10CL /10
)j =
=
( CL + PN ) / 10
(α + f ) × PTX
Io
(
α
+
f
)
×
P
+
10
PN / 10
TX
+ 10
10CL /10
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page37
Where:
‡
Pj is the transmission power of NodeB for User j
‡
CL is Downlink Coupling Loss, is equals to:
CL = PL _ DL + Lf _ BS − Ga _ antenna + Lb + SFM NSHO + Lp
z
„
PL_DL: Downlink path loss
„
Lf_BS: cable loss of NodeB
„
Ga_antenna: Gain of UE antenna and NodeB antenna
„
Lb: Body loss
„
SFMNSHO: Slow fading margin without soft handover
„
Lp: Penetration loss
Therefore:
‡
Pj
10CL /10
is the useful power received by user j
(α + f ) ×η DL _ Total × Pmax
‡
10CL /10
is the interference from own cell and adjacent cell,
and it includes Iown and Iother
‡
10 PN /10 is the noise floor of UE
Downlink Interference Analysis
z
Under the ideal power control:
( Eb / No ) j
10
10
z
=(
Ec
W 1
)j × ×
Io
Rj ρ j
Then we can get:
( Eb / No ) j
10
10
Pj =
10( CL + PN ) /10
× ρ j × PTX × (α + f +
)
PTX
W / Rj
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Where:
‡
W is the chip rate, which is 3.84Mcps
‡
Rj is the bit rate of service.
‡
ρ j is the activity factor.
Page38
Downlink Interference Analysis
z
Define the downlink load factor for user j:
( Eb / No ) j
ηj =
z
Pj
Pmax
10
=
10
PTX
10( CL + PN ) /10
)
×ρj ×
× (α + f +
Pmax
PTX
W / Rj
Define the downlink load factor for the cell:
η DL =
PTX
Pmax
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page39
The downlink load factor are defined in the transmitter side (NodeB).
Downlink Interference Analysis
z
According to the above mentioned relationship, the noise will rise:
NoiseRise =
I total PN + I own + I other No + (α + f )× PMax ×η DL / CL
=
=
PN
PN
PN
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page40
The NoiseRise is used in link budget to estimate the Interference Margin
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page41
Capacity Dimensioning Flow
Dimensioning Start
Assumed Subscribers
Load per Connection of R99
CS Average Cell Load
CS Peak Cell Load
(MDE)
PS Average Cell Load
HSPA Cell Load
Total Cell Load
No
=Target Cell Load?
Yes
Dimensioning End
Load cell −total _ UL = max{ Load CS − peak , Load CS − avg + Load PS − avg + Load HSUPA }
Load cell −total _ DL = max{ Load CS − peak , Load CS − avg + Load PS − avg + Load HSDPA } + Load CCH
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
For UL, the load per connection of R99 is calculated by the following formula:
η j = (1 + f )× L j = (1 + f )×
1
1
1+
( EbvsNo)Avg _ j
10
z
10
⋅
W 1
⋅
Rj ρ j
For DL, the load per connection of R99 is calculated by the following formula:
( Eb / No ) j
ηi =
z
Page42
Pi
=
Pmax
10
10
PTX
10( CL + PN ) /10
× (α + f +
)
Pmax
PTX
W / Rj
×ρj ×
Typical Value: ρ( j for AMR 12.2k is 0.67,f
ηUL
is 0.65,
CCH is 20%, Channel model is TU3, DL CL isα135dB,
transmission power is 43dBm)
Load per User
Uplink
ηUL
is 50%,
is 75%, load of
is 0.5, NodeB max
Downlink
AMR12.2k
1.19%
1.05%
CS64k
4.99%
5.81%
PS64k
4.77%
4.11%
PS128k
8.69%
8.03%
PS384k
21.35%
19.59%
Contents
3. Capacity Dimensioning
3.1 R99 Capacity Dimensioning
3.2 HSDPA Dimensioning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page43
Capacity Dimensioning Differences
GSM
WCDMA
z Hard blocking
z Soft blocking
z Capacity --- hardware dependent
z Capacity --- interference dependent
z Single service
z Multi services (CS&PS)
z Single GoS requirement
z Respective quality requirements of
each service
z Capacity dimensioning ---ErlangB
z Capacity dimensioning --Multidimensional ErlangB
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page44
The GSM capacity is decided by the number of carriers, it is hard capacity. But
WCDMA capacity is related to interference, coverage, channel condition, it is soft
capacity.
z
z
The Erlang-B formula is only used for
‡
Circuit switched services
‡
Single service
Multidimensional ErlangB (MDE) is suitable for:
‡
Multi service with different GoS
‡
Different service will share the same resource.
Multidimensional ElangB Principle (1)
z
Multidimensional ErlangB model is a Stochastic Knapsack Problem.
z
“Knapsack” means a system with fixed capacity, various objects arrive at
the knapsack randomly and the states of multi-objects in the knapsack
are stochastic process.
z
Then when various objects attempt to access in this system, how much is
the blocking probability of every object?
Calls
arrival
Fixed capaciy
K classes of
services
Calls
completion
Blocked
calls
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page45
Multidimensional ErlangB is a public algorithm. Now Huawei selects it. Operators can use different
algorithm to calculate the load.
Multidimensional ElangB Principle (2)
z
Case Study: Two dimensional ErlangB Model
‡
The size of service 2 is twice as that of service 1
‡
C is the fixed capacity
n2
n2
n2
States Space
3
3
Blocking States of Class 1
C
Blocking States of Class 2
C
C
2
2
2
Ω
C-b1
C-b2
1
1
1
3
2
3
4
5
6
n1
1
1
2
3
4
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
5
6
n1
1
2
3
4
5
6
n1
Page46
z
b1:size of service 1, which means the resource required by service 1 .
z
b2:size of service 2, which means the resource required by service 2 .
z
b2=2*b1
z
n1: number of service 1 connection
z
n2: number of service 2 connection
z
The left graph describes all the states (blue dots) that satisfies: n1*b1+n2*b2<=C
z
The red dots in the central graph describe the blocking states for service 1, that
means in these red states, service 1 cannot access the network.
z
The red dots in the central graph describe the blocking states for service 1, that
means in these red states, service 1 cannot access the network.
CS Capacity Dimensioning (1)
z
CS services
‡
Real time
‡
GoS requirements
Capacity
Blocking probability
Multidimensional ErlangB
‡
Resource sharing
‡
Meeting GoS requirements
Channels
64
CS
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
MDE is used to calculate the peak load.
Cell Loading
Multidimensional ErlangB Model
AM
R1
2.2
k
......
z
MDE
k
Page47
?
CS Capacity Dimensioning (2)
z
Comparison between ErlangB and Multidimensional
ErlangB
ErlangB - Partitioning Resources
Multidimensional ErlangB - Resources shared
Low Utilization of resources
High Utilization of resources
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page48
ErlangB allocate the resource according to the peak load of each service. Different
service are separate, they cannot share the resource.
z
MDE considers the probability that different service reach the peak load at the same
time is very low, then the services can share the same resource, and decrease the
resource requirement.
z
If there is only one service, MDE is the same with ErlangB.
Best Effort for Packet Services
z
PS Services:
‡
Load
Total Load
CS Peak Load
Best Effort
Load occupied by PS
‡
Retransmission
‡
Burst Traffic
CS Average Load
Load occupied by CS
Time
z
PS will use the spare load apart from that used by CS
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page49
Best effort means that the packet service can utilize the resource that is available. PS
service can be considered as BE service.
z
Retransmission of PS = BLER/(1-BLER)
z
PS traffic burst is a method to ensure the QoS, it is obtained from simulation based on
time delay requirement.
Capacity Dimensioning
z
Average load:
AverageLoad j = Traffic j × LoadFactorj
N
AverageLoadTotal = ∑ AverageLoad j
1
z
Peak load:
‡
Query the peak connection through ErlangB table
PeakLoad j = PeakConn j × LoadFactorj
PeakLoadTotal = MDE ( PeakLoad j )
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page50
Where:
‡
AverageLoadj is the average load for service j
‡
For the total average load, the result is the sum of AverageLoad for different
service
‡
PeakLoadj is the peak load for service j
‡
For the total peak load, we should calculate it by MDE. The result is lower than
the sum of PeakLoad for different service, Because it
Case Study (1)
z
Common parameters:
‡
Maximum NodeB transmission power: 20W
‡
Subscriber number per Cell: 800
‡
Overhead of SHO (including softer handover): 40%
‡
Retransmission of PS is 5%
‡
R99 PS traffic burst: 20%
‡
Activity factor of PS is 0.9
‡
Power allocation for CCH is 20% in downlink
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page51
Case Study (2)
z
Traffic Model, GoS and load factors:
GoS
Load Factors (UL)
Load Factors (DL)
0.02
2%
1.18%
0.83%
0.001
0.001
2%
4.99%
4.65%
PS64k (Kbit)
50
100
N/A
4.21%
2.96%
PS128k (Kbit)
0
100
N/A
PS384 (Kbit)
0
0
N/A
AMR12.2k (Erl)
CS64k (Erl)
UL
DL
0.02
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
5.94%
Page52
Case Study (2)
z
Uplink Average Load
z
Downlink Average Load
AMR12.2k:
AMR12.2k:
0.02*800*1.18%=18.88%
0.02*800*(1+40%)*0.83%=18.59%
CS64k:
CS64k:
0.001*800*4.99%=3.99%
0.001*800 *(1+40%)* 4.65%=5.2%
PS64k:
50*800*(1+5%)*(1+20%)/0.9/64/360
PS64k:
100*800*(1+5%)*(1+40%)*(1+20%)/0.9
/64/3600*2.96%=2.01%
0*4.21%=1.02%
CS&PS uplink average load:
PS128k: 2.02%
CS&PS downlink average load:
18.88%+3.99%+1.02%=23.89%
18.59%+5.2%+2.01%+2.02%=27.82%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page53
The difference between UL and DL is: DL should consider the soft handover, but UL
doesn’t need.
Case Study (3)
z
Uplink Peak Load
z
Downlink Peak Load
AMR12.2k:
AMR12.2k:
Traffic=0.02*800=16Erl
Traffic=0.02*800*(1+40%)=22.4Erl
Peak Conn= ErlangB(16, 2%)=24
Peak Conn= ErlangB(22.4, 2%)=31
Peak Load=24*1.18%=28.32%
Peak Load=31*0.83%=25.73%
CS64k:
CS64k:
Traffic=0.001*800=0.8Erl
Traffic=0.001*800 *(1+40%)=1.12Erl
Peak Conn= ErlangB(0.8, 2%)=4
Peak Conn= ErlangB(1.12, 2%)=5
Peak Load=4*4.99%=19.96%
Peak Load=5*4.65%=23.25%
CS Peak Load: 42.53%
CS Peak Load: 42.33%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page54
Contents
3. Capacity Dimensioning
3.1 R99 Capacity Dimensioning
3.2 HSDPA Dimensioning
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page55
HSDPA Capacity Dimensioning (1)
z
HSDPA Capacity Dimensioning
‡
The purpose is to obtain the required HSDPA power to satisfy
the cell average throughput.
‡
HS-DSCH will use the spare power apart from that of R99
Power
Pmax-R99
Power
3GPP Release 99
Unused power
HS-DSCH
Dedicated channels (power controlled)
Dedicated channels (power controlled)
Common channels
Power usage with dedicated
channels channels
Common channels
t
t
HS-DSCH with dynamic power allocation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
3GPP Release 5
Page56
HSDPA Capacity Dimensioning
‡
to obtain the average cell throughput
‡
based on HSDPA simulation result
‡
considering the gain of HSDPA scheduling
‡
the maximum data rate is limited by the available power, available codes
resource and UE capacity
‡
higher cell target load can be available for HSDPA
HSDPA Capacity Dimensioning (2)
z
Capacity Based on Simulation
‡
to simulate Ior/Ioc distribution in the
network with certain cell range
Distribution probability
4.00%
DU Cell coverage Radius=300m
3.50%
3.00%
2.50%
2.00%
1.50%
1.00%
0.50%
to simulate cell throughput distribution
4.22
2.98
2.04
1.39
0.96
0.66
0.45
0.31
0.21
0.14
0.1
0.07
0.05
0.03
0.02
0.01
0.01
0.01
0
0
0
0
0.00%
‡
Ioc/Ior
based on Ec/Io distribution in the cell
z
Conditions of Simulation
9Channel model-TU3
95 codes
Dimensioning Procedure
Cell coverage
radius
Simulation
HSDPA Power
Allocation
Ec/Io distribution
Ior/Ioc distribution
Ec/Io =>throughput
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Cell average
throughput
Page57
During the HSDPA capacity dimensioning procedure, we know the Cell Coverage
Radius (obtained from the coverage planning) and Cell Average Throughput
(obtained from the traffic model), and we want to get the HSDPA Power Allocation
based on simulation.
Case Study
z
z
Input parameters
‡
Subscriber number per cell: 800
‡
HSDPA Traffic model: 1200kbit per subs
‡
HSDPA Retransmission rate: 10%
‡
The power for HS-SCCH: 5%
‡
Cell radius: 1km
HSDPA cell average throughput:
800 *1200
* (1 + 10%) = 293kbps
3600
z
The needed power for HS-DSCH including that for HS-SCCH is 18.38%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page58
Case Study
z
Uplink Total Load of the Cell :
‡
CS Peak Load: 42.53%
‡
CS&PS average load: 23.89%
Load cell −total _ UL = max{ Load CS − peak , Load CS − avg + Load PS − avg }
= MAX ( 42 .53%, 23.89% ) = 42.53%
z
Downlink Total Load of the Cell :
‡
CS Peak Load: 42.33%
‡
CS&PS average load: 27.82%
‡
HSDPA load is 18.38%
‡
CCH load: 20%
Load cell −total _ DL = max{ Load CS − peak , Load CS − avg + Load PS − avg + Load HSDPA } + Load CCH
= MAX ( 42 .33%, 27 .82% + 18.38%) + 20% = 66.20%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page59
Base on this capacity dimensioning result, we can check whether the cell load of the
network is beyond the network target. If it is, we should adjust the cell radius.
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page60
Overview
z
Definition of a CE:
‡
A Channel Element is the base band resource required in the Node-B
to provide capacity for one voice channel, including control plane
signaling, compressed mode, transmit diversity and softer handover.
z
NodeB Channel Element Capacity
‡
One BBU3900
„
UL 1,536 CEs with full configuration
„
DL 1,536 CEs with full configuration
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page61
Due the technical features of the WCDMA, compared with the 2G systems such as
GSM, the RNC and Node B present enormous capacity. For example, for the fully
configured NodeB, the number of channels of one carrier is 128, which is more than
10 times of that supported by a TRX of GSM. One uplink processing unit of our
NODEB has the processing capacity of 128 12.2kbps voice channels. One 3*1
WCDMA BTS is equivalent to the GSM sites of one S10/10/10. At the beginning of
the WCDMA network construction, so high a capacity is not a necessity, and only a
portion of it is required (e.g., 10%). If we offer the quotation based on the maximum
hardware channel capacity of TRX like the GSM, it will make the operators incur
enormous cost and mismatch the user quantity. To reduce the initial investment, the
operator is bound to pay the equipment price to the supplier according to the actual
use capacity, and, subsequently, pay more equipment prices with the increase of the
user quantity. This way, the operator will reduce the initial investment and mitigate the
risks.
Huawei Channel Elements
Features
z
Channel Elements pooled in one NodeB
z
No need extra R99 CE resource for CCH
‡
reserved CE resource for CCH
z
No need extra CE resource for TX diversity
z
No need extra CE resource for Compressed Mode
‡
reserved resources for Compressed Mode
z
No need extra CE resource for Softer HO
z
HSDPA does not occupy R99 CE resource
‡
separate module for HSDPA
z
HSUPA shares CE resource with R99 services
z
No additional CE resource for AGCH RGCH and HICH
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page62
Softer HO CE: 3900 series NodeB doesn’t need extra CE resource, but 3800 series
NodeB needs extra CE resource
z
HSUPA shares CE resource with R99 services: that means the HSUPA E-DCH shares CE
resource with R99 services
CE Dimensioning Flow
Dimensioning Start
--Subscribers per NodeB
--Traffic model
CS Average CE
CS Peak CE
(MDE)
PS Average CE
HSPA CE
Channel Elements per NodeB
Dimensioning End
CEUL _ Total = Max (CE CS _ Peak _ UL , CE CS _ Average _ UL + CE PS _ UL + CE A _ UL + CE HSUPA )
CE DL _ Total = Max (CE CS _ Peak _ DL , CE CS _ Average _ DL + CE PS _ DL + CE A _ DL )
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page63
CE Mappings for R99 Bearers
Channel Elements Mapping for R99 Bearers
Bearer
Uplink
Downlink
AMR12.2k
1
1
CS64k
3
2
PS64k
3
2
PS128k
5
4
PS144k
5
4
PS384k
10
8
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page64
The mapping relationship of Channel Elements consumption for each bearer is based
on Uplink 2-way diversity
z
z
In the case of uplink 4-way diversity, the CE consumption is shown below:
‡
Bearers
CE (4-way diversity)
‡
AMR12.2k
2
‡
CS64k
4
‡
PS64k
4
‡
PS128k
8
‡
PS384k
16
Detailed and recently updated data should be referred to the newest issued notice of
"UMTS RAN Product Specificaiton".
R99 CE Dimensioning Principle
z
Peak CE occupied by CS can be obtained through multidimensional
ErlangB algorithm
z
Average CE needed by CS and PS depend on the traffic of each service,
i.e.
z
CE resource shared
among each service
Average CE = Traffic * CE Factor
CS Peak CE
CE occupied by PS
and HSPA
CS Average CE
Multdimensional ErlangB Model
AM
R1
2 .2
k
......
CE
Total CE
CE
Resources
CE occupied by CS
6
CS
Time
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
4k
Page65
The CE dimensioning principle is similar with capacity dimensioning.
HSDPA CE Dimensioning
z
In uplink, no CE consumption for HS-DPCCH if corresponding UL
DCH channel exists
z
In uplink, CE consumed by one A-DCH depends on its bearing
rate
z
In downlink, A-DCH is treated as R99 DCH.
z
No additional CE needed for HS-DSCH and HS-SCCH
Associated Dedicated Channels
One HSDPA link need
one A-DCH in uplink and
downlink respectively
HS
-D
S
CH
HS
-S
CC
HS
H
-D
PC
CH
Site 1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Site 2
Page66
HSDPA channels doesn’t occupy R99 CE resource, but we should calculate the A-DCH CE.
CE Mappings for HSDPA Bearers
HSDPA Channel Elements Consumption
Traffic
Uplink
Downlink
---
0 CE
HS-DPCCH
0 CE
---
UL A-DCH (DPCCH)
3 CE
---
DL A-DCH (DPCCH)
---
1 CE
HSDPA Traffic
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Page67
HSDPA Traffic:
‡
Separate dedicated module processing HSDPA Traffic so HSDPA traffic does
not occupy any R99 CE resource.
‡
z
HS-DSCH and HS-SCCH does not affect base band capacity for R99 services.
HS-DPCCH
‡
HS-DPCCH doesnot consume any R99 Channel Element since its base band
resource is reserved in BBU module.
z
UL A-DCH (DPCCH)
‡
PS64k is recommended to bear uplink user data, TCP acknowledgement and
signaling.
‡
z
One PS64k consumes 3 CE in uplink.
DL A-DCH (DPCCH)
‡
A-DCH bears DL signaling control.
‡
A-DCH can be beared on HSDPA since RAN10.0.
Case Study (1)
z
Input Parameters
‡
‡
Subscribers number per NodeB: 2000
Overhead of SHO: 30%
UL
DL
AMR12.2k (Erl)
0.02
0.02
GoS
2%
0.001
0.001
2%
PS64k (kbit)
50
100
N/A
PS128k (kbit)
0
80
N/A
HSPA (kbit)
0
1200
N/A
CS64k (Erl)
‡
R99 PS traffic burst: 20%
‡
Retransmission rate of R99 PS: 5%
‡
PS Channel element utilization rate: 0.7
‡
Average throughput requirement per user of HSDPA: 400kbps
‡
HSDPA traffic burst is 25%
‡
Retransmission rate of HSDPA is 10%
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
z
Traffic Model
Page68
In this case, the R99 traffic model includes the traffic of HSDPA UL A-DCH. That
means 50kbits for UL PS64k includes the R99 UL DCH and HSDPA UL A-DCH.
Case Study (2)
z
Uplink CE Dimensioning
z
AMR12.2:
AMR12.2:
Traffic =0.02*2000*(1+30%) = 52Erl
Traffic =0.02*2000*(1+30%) = 52Erl
Peak CE =ErlangB(52,0.02)*1= 63 CE
Peak CE =ErlangB(52,0.02)*1 = 63CE
Average CE =52*1=52 CE
Average CE =52*1=52CE
CS64:
Traffic of VP:
Traffic =0.001*2000*(1+30%) = 2.6Erl
Traffic =0.001*2000*(1+30%) = 2.6Erl
Peak CE =ErlangB(2.6,0.02)*3 = 21 CE
Peak CE =ErlangB(2.6,0.02)*2 =14CE
Average CE =2.6*3=9 CE
Average CE =2.6*2=6CE
Total peak CE for CS: 80CE
Total peak CE for CS: 74CE
Total average CE for CS: 52+9=61CE
Total average CE for CS: 52+6=58CE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Page69
Different with capacity dimensioning, the UL CE dimensioning should consider the
soft handover.
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Downlink CE Dimensioning
For the peak CE, we should use MDE to calculate.
Case Study (3)
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Uplink CE Dimensioning
CE for PS64k:
2000 * 50
* 3 * (1 + 30%)* (1 + 20%)* (1 + 5%) = 4CE
64 * 0.7 * 3600
Total CE for R99 PS services:
4CE
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Downlink CE Dimensioning
CE for PS64k:
2000 *100
* 2 * (1 + 30%) * (1 + 20%) * (1 + 5%) = 4CE
64 * 0.7 * 3600
CE for PS128k:
2000 * 80
* 4 * (1 + 30%) * (1 + 20%) * (1 + 5%) = 4CE
128 * 0.7 * 3600
Total CE for R99 PS services:
4+4=8CE
CE for HSDPA A-DCH:
2000 *1200
*1* (1 + 25%) * (1 + 10%) = 3CE
400 * 3600
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Page70
In this case, the R99 traffic model includes the traffic of HSDPA UL A-DCH, therefore
it is no need to calculate the HSDPA UL CE
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For the HSDPA DL A-DCH CE, strictly speaking, it can perform soft handover. But
usually the CE requirement is low, so in Huawei strategy, the soft handover is not
considered.
Case Study (4)
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Uplink CE Dimensioning
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Downlink CE Dimensioning
Total CE
Total CE
CEUL _ Total = Max(CECS _ Peak _ UL ,
CE DL _ Total = Max( CECS _ Peak _ DL ,
CECS _ Average _ UL + CE PS _ Average _ UL )
CECS _ Average _ DL + CE PS _ DL + CE A _ DL )
= MAX (80, 61 + 4) = 80CE
= Max(74, 58 + 8 + 3) = 74 CE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page71
Contents
1. Traffic Model
2. Interference Analysis
3. Capacity Dimensioning
4. CE Dimensioning
5. Network Dimensioning Flow
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page72
Network Dimensioning Flow
start
Coverage Requirement
UL/DL Link Budget
Cell Radius=Min (RUL, RDL)
Capacity Requirement
UL/DL Capacity
Dimensioning
Satisfy Capacity Requirement?
No
Yes
CE Dimensioning
Output NodeB Amount/
NodeB Configuration
End
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page73
Adjust Carrier/NodeB
Thank you
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