Atelier Optimisation 3G
Advanced
LZU 103 1014
Chapter 12:
RAN Transport Dimensioning Overview
Objectives of Chapter 12
Introduction
After this chapter the participants will be able to:
1. Describe the nodes and interfaces that make up the WCDMA
Radio Access Network (RAN)
2. Define the WCDMA Access Transport Network design
process
3. Describe the type of traffic carried by the WCDMA RAN
interfaces
4. Basic traffic dimensioning for required services
5. Principles of Link dimensioning
1/038 06-EN/LZU 103 1014
.
Figure 12- 1
WCDMA RAN Transmission Network Dimensioning
WCDMA RAN Interfaces and Nodes
SGSN
MSC
Iu-CS
Iu-PS
RANAG
Iur
RNC
RBS
Iub
1/038 06-EN/LZU 103 1014
.
Figure 12- 2
WCDMA RAN Transmission Network Dimensioning
RNC
Access TN Design Process
No
Nominal
Cell
Plan
Topology
Model
Development
RBS, Cluster
capacity
calculations
RNC
Iub, Iu, Iur,
Mub, Mur
Dimensioning
Topology
&
Capacity
Ok?
Nominal
Transport
Plan
Yes
Pre-Planning
Detailed
Transport
Plan
Link and
Node
Specification
RBS/ RXI/
RNC
Detailing
ATM
Detailing
Detailing
1/038 06-EN/LZU 103 1014
.
Figure 12- 3
WCDMA RAN Transmission Network Dimensioning
Detailed
Cell
Plan
WCDMA RAN Interface Traffic
RANAP
Q2630
User-Plane
Mub
Mut
Mur
RANAP
User-Plane
Router
O&M
MSC
RBS
Node Sync
NBAP-C
NBAP-D
Q2630
User-Plane
Mub
.
OSS-RC
Iu-CS
Iu-PS
RANAG
Iur
RNC
RNSAP
Q2630
User-Plane
Node Sync
NBAP-C
NBAP-D
Q2630
User-Plane
Mub& Mut
Iub
1/038 06-EN/LZU 103 1014
SGSN
Figure 12- 4
WCDMA RAN Transmission Network Dimensioning
RNC
Node Synchronization
RNC
RBS
T1
T1
T2
T1, T2, T3
Round-Trip-Time =(T4-T1)-(T3-T2)
T3
T4
1/038 06-EN/LZU 103 1014
.
Figure 12- 5
WCDMA RAN Transmission Network Dimensioning
WCDMA RAN Protocols
RNC
MSC or SGSN
RANAP
RNSAP
RBS
NBAP-D
.
RNSAP
NBAP-D
NBAP-C
NBAP-C
1/038 06-EN/LZU 103 1014
RANAP
Figure 12- 6
WCDMA RAN Transmission Network Dimensioning
RNC
ATM Signaling (Q2630)
RNC
ERQ
(Establish Request)
MSC
Q2630
RBS
Q2630
Q2630
ECF
(Establish Confirm)
Q2630
RNC
1/038 06-EN/LZU 103 1014
.
Figure 12- 7
WCDMA RAN Transmission Network Dimensioning
User Plane Interface Traffic
PCH, FACH
S-CCPCH
RACH
P-RACH
DPDCH/
DPCCH
DCH
Iub-upCCH
Iub-upDCH
Iu-ps-up
SGSN
Iu-cs-up
MSC
HS-PDSCH
HS-DSCH
Iub-up-HS
Iur-up
E-DPDCH
E-DCH
RNC
1/038 06-EN/LZU 103 1014
.
Figure 12- 8
WCDMA RAN Transmission Network Dimensioning
Management Interfaces
Mub
Mut
Mur
RNC
Router
O&M
Mur
RANAG
Mut
RBS
Mut and Mub
carried on Iub
RBS
Mub
1/038 06-EN/LZU 103 1014
.
Figure 12- 9
WCDMA RAN Transmission Network Dimensioning
OSS-RC
Radio Access Bearer (RAB)
UE
RBS
RNC
WCDMA RAN
MSC/
SGSN
Radio Access Bearer (RAB)
Radio Bearer (RB)
User plane
TRCH
Radio
Link (RL)
RRC
TRCH
Iu Bearer
RANAP
Signalling Radio Bearer (SRB)
Signalling Connection
1/038 06-EN/LZU 103 1014
.
Figure 12- 10
WCDMA RAN Transmission Network Dimensioning
RANAP
Dimensioning Service Types
AMR Speech 12.2 kbps
CS 64 kbps
Streaming 16 kbps
Interactive UL:64 DL:64
SRB 3.4 kbps
HSxPA* ??? kbps
* Rate determined by UE environment
and RBS load
1/038 06-EN/LZU 103 1014
.
Figure 12- 11
WCDMA RAN Transmission Network Dimensioning
CS Traffic Conversion
An ‘Erlang’ is defined as one busy circuit for one hour. If the
Mean Holding Time (MHT) and Busy Hour Call Attempts
(BHCA) of a system can be determined then traffic per sub for the
Busy Hour (BH) can be determined using the formula below:
Traffic (A) = BHCA X MHT
Where
BHCA = Busy Hour Call Attempts
MHT = Mean Hold Time (in hours)
1/038 06-EN/LZU 103 1014
.
Figure 12- 12
WCDMA RAN Transmission Network Dimensioning
CS Traffic Conversion Example
Calculate the traffic for the Voice and CS 64 services given the
Busy Hour Call Attempts (BHCA) and Mean Hold Times
(MHT) below:
BHCA = 0.5, MHT = 3 min => Traffic =
AMR Speech 12.2
_______
mE
25
Traffic (A) = BHCA X MHT
BHCA = 0.2, MHT = 6 min => Traffic =
_______
mE
20
CS 64
HINT: MHT must be in hours (MHT/60)
1/038 06-EN/LZU 103 1014
.
Figure 12- 13
WCDMA RAN Transmission Network Dimensioning
R99 PS Traffic Conversion
1 hour
x kbps
kbps X 3600
R99_PSsub_traffic =
1.024 X 8
[Kbyte/h]
Where:
kbps = Sub bit rate [kbps]
3600 = Seconds in 1 hour
1.024 = Conversion 103 (throughput) to 210 (storage)
8 = Bits in a Byte
1/038 06-EN/LZU 103 1014
.
Figure 12- 14
WCDMA RAN Transmission Network Dimensioning
HSDPA Traffic Conversion
Data
HSDPA
Data
Data
HSDPAsub_traffic =
GByte/month x 1024
[Kbyte/BH]
30 x 10
Where:
GByte/month = Sub monthly download limit [GByte]
30 = Days in 1 month
10 = Subscriber active hours in 1 day
1024 = Kbyte in GByte
1/038 06-EN/LZU 103 1014
.
Figure 12- 15
WCDMA RAN Transmission Network Dimensioning
HSDPA Cell Capacity Rate
HSDPA
HSDPAsub_traffic X 8 X 1.024
HSDPA = N
X PF X (1+Retransm.)
subs X
Cell_Cap
3600
[kbps]
Where:
Nsubs = Subs per Cell
HSDPAsub_traffic = HSDPA Subscriber BH traffic [Kbyte/BH]
PF = PS Peak Factor (eg. 1.4)
Retransm. = PS retransmission rate (eg. 1% = 0.01)
1/038 06-EN/LZU 103 1014
.
Figure 12- 16
WCDMA RAN Transmission Network Dimensioning
HSUPA Traffic Conversion
Data
HSUPA
Data
Data
HSUPAsub_traffic =
GByte/month x 1024
[Kbyte/BH]
30 x 10
Where:
GByte/month = Sub monthly upload limit [GByte]
30 = Days in 1 month
10 = Subscriber active hours in 1 day
1024 = Kbyte in GByte
1/038 06-EN/LZU 103 1014
.
Figure 12- 17
WCDMA RAN Transmission Network Dimensioning
HSUPA Cell Capacity Rate
HSUPA
HSUPAsub_traffic X 8 X 1.024
HSUPA = N
X PF X (1+Retransm.)
subs X
Cell_Cap
3600
[kbps]
Where:
Nsubs = Subs per Cell
HSUPAsub_traffic = HSUPA Subscriber BH traffic [Kbyte/BH]
PF = PS Peak Factor (eg. 1.4)
Retransm. = PS retransmission rate (eg. 1% = 0.01)
1/038 06-EN/LZU 103 1014
.
Figure 12- 18
WCDMA RAN Transmission Network Dimensioning
Average Subscriber Traffic Profile
The average subscriber uses
all of the offered services
Average Sub CS Traffic = mE X Subs using Service
Average Sub R99 PS Traffic = KByte/h X Subs using Service
Average HSxPAsub_traffic = KByte/BH X Subs using Service
Eg. 10% of subs use 20mE of CS64 => Average sub CS64 = 2mE
1/038 06-EN/LZU 103 1014
.
Figure 12- 19
WCDMA RAN Transmission Network Dimensioning
WCDMA RAN Link Dimensioning
RANAP
Q2630
User-Plane
Mub
Mut
Mur
RANAP
User-Plane
Router
O&M
MSC
RBS
Node Sync
NBAP-C
NBAP-D
Q2630
User-Plane
Mub
.
OSS-RC
Iu-CS
Iu-PS
RANAG
Iur
RNC
RNSAP
Q2630
User-Plane
Node Sync
NBAP-C
NBAP-D
Q2630
User-Plane
Mub& Mut
Iub
1/038 06-EN/LZU 103 1014
SGSN
Figure 12- 20
WCDMA RAN Transmission Network Dimensioning
RNC
Soft Handover Factor (F_SHO)
Planned RBS Boundary
RBS 1
RBS 2
RBS traffic = N_subs x Traffic per sub x (1+F_SHO)
Typical value = 0.44
1/038 06-EN/LZU 103 1014
.
Figure 12- 21
WCDMA RAN Transmission Network Dimensioning
Retransmission Factor (F_RETRAN)
Transmitter
Receiver
8
7
6
5
4
3
2
1
RBS traffic = N_subs x Traffic per sub x (1+F_RETRAN)
Typical value = 0.01
Status Indication
8
1/038 06-EN/LZU 103 1014
.
Figure 12- 22
7
6
5
WCDMA RAN Transmission Network Dimensioning
4
3
2
1
Normalized Channel Throughput
Channel Efficiency Factor (F_EFF)
Capacity Requirement = traffic requirement X F_EFF
Typical values = 0.75 or 0.8 for HSDPA
Normalized Offered Traffic
1/038 06-EN/LZU 103 1014
.
Figure 12- 23
WCDMA RAN Transmission Network Dimensioning
HS-DSCH Overhead Example
RLC_SDU
RLC Header (2)
RLC_PDU/MAC-d SDU
MAC-d Header (0)
MAC-d PDU
FP Header & CRC (9)
Spare extension & padding (1)
SSCS SDU
SSCS Header (3)
.
SSCS
PDU/CPS SDU
CPS Header (1)
ATM Header (5)
32
8 = 40
= 1.48
5
13
1/038 06-EN/LZU 103 1014
9
.
12
Figure 12- 24
5
1
WCDMA RAN Transmission Network Dimensioning
= 27
HS-DSCH Iub Overhead Factor
F_IUB_OH
1,7
F_IUB_OH
1,6
BE-DCH
E-UL
HS-DSCH
1.33
1.33
1.32
1,5
1,4
1.33 for 8 RLC PDUs
1,3
0
5
10
15
20
Number of PDUs per Data Frame
1/038 06-EN/LZU 103 1014
.
Figure 12- 25
WCDMA RAN Transmission Network Dimensioning
25
E-UL ACK/ACK Factor (F-ACK)
ACK
ACK
ACK
ACK
RNC
RNC
90% probability
RNC
10% probability
E-UL Soft handover factor = F_SHO X F_ACK
F_ACK = probability of ACK from all RBSs = 10% or 0.1
1/038 06-EN/LZU 103 1014
.
Figure 12- 26
WCDMA RAN Transmission Network Dimensioning
Single Service Blocking Probability
3 Erlangs
Speech
(16.1 mE)
Line (1 Erlang)
16.1 mE X 150 = 2.4 E
Line (1 Erlang)
Line (1 Erlang)
Blocking Probability (PB) =?
1/038 06-EN/LZU 103 1014
.
Figure 12- 27
WCDMA RAN Transmission Network Dimensioning
Erlang B Blocking Probability Formula
AN
PB =
N!
Σ
AK
K!
For K= 0 to N
Where:
A = Required Traffic in Erlangs
N = Number of Lines
1/038 06-EN/LZU 103 1014
.
Figure 12- 28
WCDMA RAN Transmission Network Dimensioning
Multi-service Dimensioning Example
5 Erlangs
Line (1 Erlang)
Line (1 Erlang)
C1 = 20 mE X 50 = 1 E
C2 = 5 mE X 50 = 0.25 E
Line (1 Erlang)
Line (1 Erlang)
Line (1 Erlang)
C1 = CS Data (1 line & 20 mE)
C2 = CS Data (2 lines & 5 mE)
1/038 06-EN/LZU 103 1014
.
Figure 12- 29
WCDMA RAN Transmission Network Dimensioning
Kaufman-Roberts algorithm
bi 1
PBi 
 q(C  i)
i 0
C
 q( j )
1 k
q( j )   ai bi q( j  bi )
j i 1
j 0
where
C
k
ai
bi
q(j)
1/038 06-EN/LZU 103 1014
is the number of resources (C units).
is the number of service classes.
is the offered traffic.
is the resource required for each service.
is the distribution of the number of resource units occupied.
.
Figure 12- 30
WCDMA RAN Transmission Network Dimensioning
Overhead included in Equivalent BW
SRB
Radio Network layer
User Plane
RLC Header
MAC Header
FP Header
Transport Network layer
SSCS Header
AAL2 Payload
(47 Bytes)
1/038 06-EN/LZU 103 1014
.
Figure 12- 31
WCDMA RAN Transmission Network Dimensioning
AAL2 Equivalent Bandwidth
Radio Bearer
UL
[kbps]
DL
[kbps]
CS Conversational Speech 12.2 kbps (AMR 12.2)
14.6
13.7
CS Conversational Data 64 kbps (CS 64)
73.5
72.5
CS Conversational Data 64 kbps (CS 64) + PS Interactive 8/8 kbps
84.3
82.9
CS Streaming Data 57.6 kbps (CS 57.6)
64.3
63.8
PS Interactive 64 kbps (PS 64/64)
77.8
76.8
PS Interactive 64/128 kbps (PS 64/128)
77.8
150.2
PS Interactive 64/384 kbps (PS 64/384)
77.8
445.9
PS Interactive 64/HSDPA (PS 64/HSDPA)
76.0
PS Interactive 384/HSDPA (PS 384/HSDPA)
439.2
SRB
1.3
PS Streaming 16/64 kbps + PS Interactive 8/8 kbps (PS 16/64)
33.0
82.7
PS Streaming 16/128 kbps + PS Interactive 8/8 kbps (PS 16/128)
34.3
155.1
1/038 06-EN/LZU 103 1014
.
Figure 12- 32
WCDMA RAN Transmission Network Dimensioning
1/038 06-EN/LZU 103 1014
.
Figure 12- 33
WCDMA RAN Transmission Network Dimensioning