RF Tuning Workshop
Agenda
•
•
•
•
Introduction
Basic Principles
RF Initial Tuning Overview
Case Study
Introduction
WCDMA Network Initial Tuning is aimed to make
the network to be ready for launch in term of
Accessibility, Retainability, and Integrity.
Basic Principles
Basic Principles
• WCDMA General Priniciple
• Ericsson WCDMA RAN Functionality
WCDMA General Principle
Spectrum Allocation
1850
1900
1950
2000
2050
2100
2150
2200
2250
2010 MHz
ITUAllocations
1885 MHz
Europe
2025 MHz
UMTS
GSM1800 DECT
MSS
1850 MHz WLL
UMTS
MSS
2170 MHz
WLL
IMT 2000
GSM1800
MSS
2170 MHz
2110 MHz
1980 MHz
1880 MHz
China
IMT 2000
MSS
IMT 2000
1885 MHz
MSS
IMT 2000
MSS
IMT 2000
MSS
1980 MHz
1885 MHz 1918 MHz
Japan
Korea (w/o PHS)
PHS
IMT 2000
MSS
1895 MHz
North
America
2160 MHz
PCS
AA D B
1850
EF C
1900
AA D B
1950
EF C
M
Reserve D
MSS
S
MSS
2000
2050
2100
2150
2200
2250
UMTS Spectrum
Frequency Division Duplex; 2x60 MHz
UTRA Paired Band: WCDMA
Uplink:
1920-1980 MHz
Downlink: 2110-2170 MHz
TDD
1900
FDD UL
1950
MSS TDD
2000
Time Division Duplex
UTRA Unpaired Band:
UTRA TDD & TD-SCDMA
1900-1920 MHz and 2010-2025 MHz
FDD DL
2050
2100
2150
MSS
2200
f
MHz
Mobile Satellite Service; 2x30 MHz
Uplink:
1980-2010 MHz
Downlink: 2170-2200 MHz
Direct Sequence CDMA
• Separate users through different codes
• IS-95 (1.25 MHz)
• Large bandwidth
• CDMA2000 (3.75 Hz)
• Continuous transmission and reception
t
MS 1
MS 2
MS 3
Code
f
5 MHz
• WCDMA (5 MHz)
Coding Concept
User Information bits are multiplied with the
quasi random bits called chips causing the
information to be spread over a wide bandwidth
Orthogonal
Code 1
Orthogonal Codes provide unique
identification of each data channel
Sync.
Bits
Orthogonal
Code 2
Control/
Signaling
Data
Spread Spectrum (PN) Codes
provide unique identification
of each transmitter
Error
Error
Protection
Protection
Spread
Spectrum
(PN or Gold)
Code
Orthogonal
Code 3
Vocoder
Vocoder
Error
Error
Protection
Protection
Linear
Linear
Summation
Summation
Orthogonal
Code 4
User Data
Channel 1
Filtering
Filtering
++
RF
RF
Modulation
Modulation
RF
Out
Error
Error
Protection
Protection
Orthogonal
Code N
User 1
User 2
User 3
User Data
Channel N
Error
Error
Protection
Protection
...
Frequency
Orthogonal Code
Orthogonal Code
• Known as Channelization Code
• The output is a stream of bits, which is called
Chip
• Chip Rate for WCDMA is 3.84 Mbps
• Used to differentiate data channels within the
Users
Scrambling Code
•
•
•
•
•
Known as Pseudo Noise Code (PN)
512 Primary Scrambling Codes DL
Several million codes UL PN code 1
PN code 1
PN code 4
Differentiate RBS in DL PN code 3
Differentiate user in UL BS 1 transmits on PN code 1
PN code 2
PN code 5
PN code 2
PN code 6
BS 2 transmits on PN code 2
Ericsson WCDMA RAN
Functionality
Network Architecture
Ericsson P4 RAN Feature
•
•
•
•
Handover
Power Control
Channel Switching
Capacity Management
Handover
Capability
• Allow UE to have mobility in the connected
mode with maintained quality and minimum
resource utilization
Type of Handover
• Soft/Softer Handover
• IFHO
• IRAT
Handover Flow
RNC
UE
MEASUREMENT CONTROL
Perform Measurements
UE evaluation
MEASUREMENT REPORT
Evalutation
Radio Link
Add/Remove/Replace?
Execution
Radio Link
Allocation/deallocation
ACTIVE SET UPDATE
Radio Link
Add/Remove/Replace
ACTIVE SET UPDATE COMPLETE
Monitored set
calculation
MEASUREMENT CONTROL
Perform Measurements
UE evaluation
MEASUREMENT REPORT
Power Control
Capability
• Maintain good quality connection
• Minimize UL and DL power utilization
Power Control “basic types”
Power control on COMMON
CHANNELS ensures there is
sufficient coverage to
establish connections and
transfer date on common
transport channels
Power control on DEDICATED
CHANNELS (DCH) ensures
sufficient connection quality
while minimizing impact on
other connections.
Cell set-up and cell reconfiguration
Common transport
channel setup and reconfiguration
Radio Link Setup
Power Balancing
RAB Establishment
Soft Handover (SOHO)
Compressed Mode
Inter-Frequency Handover
Power Control on DCH - Overview
The RBS and UE uses Inner Loop to
send UL and DL TPC’s (transmit
power commands). The TPC’s are
determined by the outer loop
power control.
The RNC and UE uses Outer Loop
power control to calculate UL and
DL quality targets to which the UE
and RNC shall adjust its
transmitted power.
P(SIR-Target,UL)
Inner loop
DL-TPC
ULTPC
UL-Outer loop
RNC
SIR-Target,UL
P(SIR-Target, DL)
SIR-Error,UL
DL-Outer loop
BLER-Measured,DL
SIR-Target,DL
BLER = Block Error Rate
SIR = Signal to Interference Ratio
TPC = Transmit Power Control
Open loop
P(Startvalue)
Initial Power Setting in UL and DL uses Open
Loop. It ensures reliable connection setup,
minimal impact on existing connections (UL) and
avoids excessive power (DL).
Common
Channel
Setting Common
Channel Powers Power
PCPICH: ‘primaryCpichPower’: default = 270(27 dBm)
Broadcast Channel: ‘bchPower’: default = -31 (-3.1 dB)
AICH: ‘aichPower’: default = -6 (-6 dB)
FACH (control): ‘maxFach1Power’: default =18 (1.8 dB)
FACH (traffic): ‘maxFach2Power’: default =15 (1.5 dB)
RBS
Paging channel: ‘pchPower’:default =-4 (-0.4 dB)
Paging indication ch: ‘pichPower’: default =-7 (-7 dB)
Primary SCH: ‘schPower1’: default =-18 (-1.8 dB)
Secondary SCH: ‘schPower2’: default =-35 (-3.5 dB)
5/ 038 13 - EN/LZU 108 5686 PA15
11
WCDMA Radio Network Functionalit y
Channel Switching
Capability
• Optimize the utilization of the radio resources
by switching the UE to the most suitable
transport channel based on the traffic volume,
radio resource availability, radio condition,
and mobility
• Only apply to I/B Packet Services
Channel Switching Types
Connected Mode
1. Common to Dedicated
Dedicated Channel (Cell_DCH)
Cell_DCH 64/384 kbps UL/DL
2
2
2. Dedicated to dedicated
Cell_DCH 64/128 kbps UL/DL
2
2
3
Cell_DCH 64/64 kbps UL/DL
3. Dedicated to common
1
Common Channel (Cell_FACH)
RACH/FACH
(max. 32 kbps)
4
Idle Mode
4. Common to Idle Mode
Common to Dedicated Evaluation
Monitors if the UE shall be switched from a common to a dedicated transport channel due
to large amount of user data buffered in the RNC or the UE.
Connected Mode
UL RLC
buffer load
Dedicated Channel
(Cell_DCH)
Up-switch
Cell_DCH
64/384 kbps UL/DL
X
ulRlcBufUpswitch [256 bytes]
Cell_DCH
64/128 kbps UL/DL
and/or
Cell_DCH
64/64 kbps UL/DL
Common Channel
(Cell_FACH)
RACH/FACH
Idle Mode
DL RLC
buffer load
Up-switch
A request is sent to
Admission Control to
perform an up-switch
from Cell_FACH to
Cell_DCH 64/64 kbps
X
dlRlcBufUpswitch [500 bytes]
Dedicated to Dedicated Coverage
triggered Down-Switch Evaluation
Monitors if a switch to a lower rate radio bearer is required due to coverage.
DL TX code power > [Power Alarm Threshold], defined as Max Code Power –
downswitchPwrMargin. A down-switch to Cell_DCH with lower bitrate is
requested. Timer coverageTimer starts.
Connected Mode
Pcode
Dedicated Channel
(Cell_DCH)
Cell_DCH
64/384 kbps UL/DL
Cell_DCH
64/128 kbps UL/DL
Cell_DCH
64/64 kbps UL/DL
Common Channel
(Cell_FACH)
RACH/FACH
Idle Mode
DL TX code power < [Power
Alarm Threshold] –
reportHysteresis while the timer
is running, the down-switch
request is cancelled.
DL TX code power > [Power Alarm
Threshold] – reportHysteresis and timer
coverageTimer expires. The downswitch is executed.
Dedicated to Dedicated Up-Switch
Evaluation
DL throughput is > 90 % of max. possible bitrate on current radio bearer AND the
DL code power is < [Power up-switch threshold] – reportHysteresis, where the
[Power up-switch threshold] is defined as Max Code Power –
downswitchPwrMargin – Estimated Power Increase – upswitchPwrMargin. Timer
upswitchTimer starts.
Monitors if the throughput becomes close to the max user bandwidth and switch to the
next higher bitrate radio bearer is required.
Connected Mode
Dedicated Channel
(Cell_DCH)
Cell_DCH
64/384 kbps UL/DL
Cell_DCH
64/128 kbps UL/DL
Pcode
DL throughput is < 90 % of
max. possible bitrate on
current radio bearer OR the
DL code power becomes >=
[Power up-switch threshold]
while the upswitchTimer is
still running. The timer stops
and no up-switch is executed.
[2.9 dB for up-switch from 64-to-128 kbps]
[4.7 dB for up-switch from 128-to-384 kbps]
Cell_DCH
64/64 kbps UL/DL
Common Channel
(Cell_FACH)
RACH/FACH
Idle Mode
DL throughput is > 90 % of max. possible bitrate of current RB AND the DL code power is
< [Power up-switch threshold] when timer upswitchTimer expires. The up-switch request is sent Admission Control.
Dedicated to Common Evaluation
Monitors if a switch from a Cell_DCH to Cell_FACH is required due to a decrease in
transmitted user data.
UL and DL throughput increases
above threshold
downswitchTimerThreshold before
the timer expires. The timer stops
and no down-switch occurs.
Connected Mode
Dedicated Channel
(Cell_DCH)
Cell_DCH
64/384 kbps UL/DL
Cell_DCH
64/128 kbps UL/DL
DownswitchTimer
DownswitchTimer
Cell_DCH
64/64 kbps UL/DL
Common Channel
(Cell_FACH)
RACH/FACH
Idle Mode
UL and DL throughput falls below
threshold defined by parameter
downswitchThreshold and timer
downswitchTimer starts.
The timer expires and a request is
issued to down-switch from
common to dedicated channel.
Common to Idle Evaluation
Monitors if a switch from Cell_FACH to Idle mode is required due to a complete lack of
user data transmission.
Connected Mode
Dedicated Channel
(Cell_DCH)
Cell_DCH
64/384 kbps UL/DL
Cell_DCH
64/128 kbps UL/DL
Cell_DCH
64/64 kbps UL/DL
Common Channel
(Cell_FACH)
RACH/FACH
Idle Mode
If both the UL and DL throughput is zero for a duration
specified by parameter inactivityTimer, a request is sent to
the Connection Handling function and further to Core via Iu,
to release the connection.
Capacity Management
Capability
• Control the load in the cells and enable the
system to provide requested QoS and
coverage for the UE
Associated features
• Admission Control
• Congestion Control
• Dedicated Monitored Resource Handling
Overview of Capacity Management
Channel Switching
Admission
Control Admission
Congestion
Control
policies
“Resolves”
Admission
request
“Prevents”
Dedicated Monitored Resource Handling
Parameters
Monitored resources
Compressed Mode
& DL spreading
DL code
utilization
Air interface
Speech Equivalent
(ASE)
DL transmitted power
UL received total
wideband power
(RTWP)
Periodic and event Measurements
RBS HW
utilization
DL code
Channelization
Codes monitor
Histogram monitor
DL transmitted
carrier power
monitor
ASE monitor
RTWP monitor
RBS HW utilization
Monitors
DL code
utilization
Compressed Mode
& DL spreading
DL transmitted
power
Air interface
Speech Equivalent
(ASE)
UL received total
wideband power
(RTWP)
RBS HW utilization
DL code tree utilization (SF for users and CCH’s)
Provides info about # of connections with a certain SF. This
adds information about DL channelization usage. Also
measure # of connections in compressed mode.
Downlink transmitted power, which is affected by # of users,
the type of connections and radio conditions in the cell
Estimates UL and DL air-interface usage per radio link.
Total received UL power, i.e. information about UL
interference.
Monitors the available HW resources (channel elements)
in the RBS)
Admission Request
Admission
Control
Admission
Request
Non-guaranteed, non-HO
Non-Guaranteed, HO
Guaranteed, non-HO
Guaranteed, HO
Resource
Utilization
information
Dedicated Monitored
Resource Handling
Guaranteed service class
• SRB
• AMR 12.2
• CS 57.7
• CS 64
• PS streaming 16/64
Admission
Request Attributes
Setup type (HO or not)
Service class (guaranteed or not)
Add’l Compressed mode resources (if any)
Add’l DL TX power (if any)
Add’l DL channelization code resources (if any)
Additional ASE’s needed in UL or UL (if any)
Non-guaranteed service class
• PS 64/64
• PS 64/128
• PS 64/384
• Multi-RAB (speech+PS 64/64)
DL Channelization Code Admission Policy
Reserves HO code capacity, by blocking
guaranteed & non-guaranteed non-HO
requests if too high DL code tree usage
Traffic class / Setup type
• Non-guaranteed / non-HO requests blocked when
current DL code resource usage exceeds
dlCodeAdm - beMarginDlCode
• Guaranteed / non-HO requests blocked when
current DL code resource usage exceeds dlCodeAdm
• Soft congestion is triggered
ng non-HO
requests
g non-HO
requests
Block & soft congestion
Block & soft
congestion
beMarginDlCode
dlCodeAdm
% of DL code
tree used
Soft Congestion
Soft Congestion implies down-switching an existing non-guaranteed service to a
lower DL bitrate due to blocking of a non-guaranteed HO or non-HO request for
lower rate or guaranteed HO or non-HO request.
Down-switch of non-guaranteed service
Service class of blocked HO or
non-HO admission request
Non-guaranteed 384 kbps
From
To
No down-switch
Order of sequence
N/A
Non-guaranteed 128 kbps
384 kbps
128 kbps
N/A
Non-guaranteed 64 kbps
384 kbps
128 kbps
1
128 kbps
64 kbps
2
384 kbps
128 kbps
1
128 kbps
64 kbps
2
Guaranteed
Histogram Admission Policy
Controls the SF usage, by blocking non-guaranteed HO and non-HO
requests if the DL SF usage and/or compressed mode usage is too
high (a way of ensuring distribution of code tree utilization between
services)
• Blocks an admission that requests a radio link in
compressed mode, when the current number of radio
links in compressed mode exceeds parameter
compModeAdm.
Blocked
• Non-guaranteed HO / non-HO requests demanding SF32
blocked if the usage of this SF exceeds sf32Adm.
Blocked
• Non-guaranteed HO / non-HO requests demanding SF16
blocked if the usage of this SF exceeds sf16Adm.
Traffic class / Setup type
Blocked
• Non-guaranteed HO / non-HO requests demanding SF8
blocked if the usage of this SF exceeds sf8Adm.
sf16Adm
sf32Adm
sf8Adm
Spreading
Factor (SF)
SF 8
384 Kbps
SF 16
128 Kbps
SF 32
64 kbps
DL Transmitted Carrier Power Admission
Policy
Blocks guaranteed and nonguaranteed HO and
non-HO requests if the DL power
utilization is too high
Traffic class / Setup type
ng non-HO
requests
ng HO
requests
g non-HO
requests
g HO
requests
•
Non-guaranteed / non-HO requests blocked when current DL power
utilization exceeds pwrAdm – beMarginDlPwr
•
Guaranteed and non-guaranteed HO and non-HO requests blocked
when current DL power utilization exceeds pwrAdm
•
Guaranteed HO requests blocked when current DL power utilization
exceeds pwrAdm + pwrAdmOffset
•
Soft congestion is triggered
Block & soft congestion
Block & soft congestion
Block & soft congestion
Block & soft
congestion
beMarginDlPwr
pwrAdmOffset
pwrAdm
DL Power
usage
Set in relation to parameter
maximumTransmissionPower , which is the
configured maximum power for all DL channels
added together, to be used simultaneously in a
cell. The current default setting assumes a max.
feeder loss of 6 dB.
ASE Admission Policy
Blocks guaranteed and non-guaranteed HO and non-HO requests if the airinterface utilization in the UL and/or DL is too high
Traffic class / Setup type
Traffic class / Setup type
ng non-HO
requests
ng HO
requests
g non-HO
requests
g HO
requests
ng non-HO
requests
ng HO
requests
g non-HO
requests
g HO
requests
Block
Block
Block
Block
beMarginAseUl
aseUlAdmOffset
aseUlAdm
UL ASE
usage
Block
Block
Block
Block
beMarginAseDl
aseDlAdm
DL ASE
usage
•
Non-guaranteed / non-HO requests blocked when UL ASE
usage exceeds aseUlAdm – beMarginAseUl
•
Non-guaranteed / non-HO requests blocked when UL ASE
usage exceeds aseDlAdm – beMarginAseDl
•
Non-guaranteed HO requests and guaranteed non-HO
requests blocked when UL ASE usage exceeds aseUlAdm
•
Non-guaranteed HO, guaranteed non-HO and guaranteed
HO requests blocked when UL ASE usage exceeds aseDlAdm
•
Guaranteed HO requests blocked when UL ASE usage
exceeds aseUlAdm + aseUlAdmOffset
Congestion Control
“Congestion”
2
3
Congestion
Control
Admission
Control
5
1
4
1
Dedicated Monitored
Resource Handling
DL transmitted
power
UL received total
wideband power
(RTWP)
Cell(s)
1.
Event based measurements
2.
Congestion detected
3.
Order Admission Control to block new
connection requests
Send periodic measurements (1/s)
until congestion resolved
Initiate congestion resolve actions.
4.
1
1
Event based
Measurements
4
Periodic
Measurements
5.
Congestion detection
DL congestion detection
DL TX
carrier power
UL congestion detection
UL Received
Total Wideband
Power
DL congestion
detected
pwrAdm+
pwrAdmOffset
+ pwrOffset
UL congestion
detected
U congestion
resolved
iFCong +
iFOffset
DL cong.
resolved
pwrAdm+
pwrAdmOffset
pwrHyst
pwrHyst
iFCong
Time
•
DL cell congestion occurs when the DL carrier power
exceeds the configurable threshold
pwrAdm + pwrAdmOffset + pwrOffset for a duration longer
than pwrHyst.
•
DL cell congestion is considered resolved when the DL
carrier power is below the configurable threshold
pwrAdm + pwrAdmOffset for a duration longer than
pwrHyst.
iFHyst
iFHyst
Time
•
UL cell congestion occurs when the UL RTWP exceeds the
configurable threshold
iFCong + iFOffset for a duration longer than iFHyst.
•
UL cell congestion is considered resolved when the UL RTWP
is below the configurable threshold iFCong for a duration
longer than iFHyst.
Congestion resolve handling
“UL Congestion”
Congestion
Control
Block new guaranteed non–HO and
new non-guaranteed non-HO requests
Admission
Control
“DL Congestion”
Congestion
Control
Block ALL new requests
Start congestion resolve
actions in the cell
Admission
Control
Cell(s)
Downlink congestion resolve
handling
Mix of non-guaranteed and guaranteed connections in congested cell
tmCongAction
tmCongActionNg
DL TX
carrier power
DL congestion
detected
pwrAdm+
pwrAdmOffset
+ pwrOffset
tmCongAction
DL cong.
resolved
pwrAdm+
pwrAdmOffset
releaseAseDlNg
releaseAseDl
releaseAseDlNg
releaseAseDl
1. An amount of ASE resources equal to
releaseAseDlNg that are associated with
non-guaranteed services are released
immediately when congestion is detected. If
there are still non-guaranteed services in the
cell, timer tmCongActionNg starts.
2. If congestion prevails, releaseAseDlNg
amount of ASE resources associated with
non-guaranteed services are released
periodically every time tmCongActionNg has
Time
started and expires (until the congestion is
resolved).
Release order of non-guaranteed services
(from highest to lowest ASE in each group)
1.
Non-guaranteed where radio link originated over Iu (to common)
2.
Non-guaranteed where radio link originated over Iur(terminated radio link)
3.
When no non-guaranteed services are left and congestion prevails, the congestion
resolve action continues as per slide 30 (only guaranteed services).
3. If congestion still prevails and there are only
guaranteed services in the cell,
tmCongAction starts. When it expires,
releaseAseDl amount of ASE resources
associated with guaranteed services are
released (periodically every time
tmCongAction has started and expires, until
the congestion is resolved).
RF Initial Tuning Overview
 Workflow
 Tool
Overall Process
Tuning Team
Data Preparation
Work Flow
KPI & Plots
Data Collection
TEMS Log
files
Change Request
Analysis
Need Detailed Analysis
Post Processing
Change Request
O&M Team
Support Team
UETR & Trace
Setup
UETR Log
files
Detailed Analysis
Site Availability
Check
Alarm Check &
Site Healthy
Check
RNC Trace
files
Alarm Lists
TR & CSR
Problem Category
Initial Tuning Basic Concept
• Optimise tilts
– Reduce Pilot Pollution
– Reduce Active Set Size
– Maximise EcIo and RSCP
• Optimise Neighbour lists
– Maximise mobility
– Decrease HO Failures
• Identify Network Faults
– HW installation errors
– UTRAN problems
Tools
• TEMS Investigation
– Scanner
– UEs
•
•
•
•
•
NeXplorer
MCOM3g
UETR Explorer
Post Processing Tool (KPI Calculation)
RF Problem Sheet
Case Study
Case Study
RF Issue
• Pilot Pollution
• Low Coverage, Quality
• Missing Neighbor
• Uplink Coverage Problem
• Uplink Interference
Network Issue
• Swapped Feeder
• Neighbor Definition (Site Down)
• Co SC Issue
• AAL2 Failure
UE Issue
• UE Frozen
• No acknowledge at Preamble
RF Issue
Pilot Pollution
Pilot Pollution is defined to be the degradation
in Ec/No of the best serving pilot owing to the
presence of the other pilot signals received at
a similarly high level, but which do not
contribute constructively to the received
signal.
While
• Threshold_PilotPollution = ReportingRange1b
(5dB)
Pilot Pollution (2)
Low Coverage, Quality
Low Coverage & Quality
Missing Neighbor
• Required Neighbor Relation is not defined
• The Cell becomes interferer
• Call drop when the delta of the RF
measurement between the cell and the best
cell is greater than releaseConOffset
Missing Neighbor (2)
Uplink Coverage Problem
Uplink Interference
Network Issue
Swapped Feeder
Neighbor Definition (Site Down)
Co Scrambling Code Issue
Co Scrambling Code Issue (2)
Neighbour list & combination
Active set
Neigbour list is
defined every cell
individually but
must be combined
in a unique list
when handovering
Monitored set – the union of neighbours from all cells in the active set
Duplicate cells
are removed
Neighbour list & combination
•
•
•
•
Neighbour combination
accordes to NB combination
algorithm.
Shared NB cells only could be
added once a time.
The maximum cells of monitor
set is restricted by
C_MaxSohoListSubset (=32)
Redundant cells exceeding
C_MaxSohoListSubset in the
monitored set should be
removed.
max 32 cells
cell A31
Truncated cells- ”unmonitored set”
cell B31
cell C31
cellx
Undefined neighbors
celly
NB Combination Algorithm
NB combination
algorithm ran at
RNC side
Sample: e1a
no DRNC
1. Setup a call: intially UE use the NB list contained
in SIB 11.
2. Then RRC connection completed, first
measurement control will be sent down to UE
to tell what NB list should be used.
1.Setup a call
2.Measurement
control
Moved to a new cell
Continually listen the
system information on
BCH- SIB 11 gives the
neigbour information
3.Active set
update
4.measurement
control
3. With moving to new cell, active set update
would occur, then RNC combines two neigbour
sets into one unique monitored set list.
4. New measurement control will be sent after
active set updated. Contains the new
monitored set information for UE.
NB Combination Algorithm
A
B
C
A1
B1
C1
A2
B2
C2
A3
B3
C3
A4
B4
C4
A5
B5
C5
A
B
A1
B1
e1b cell C
dropped
A2
B2
A3
B3
A4
B4
A5
B5
e1a, new
cell D
added,it
has 32 NBs
in its
neigbourlis
t
A
B
D
A1
B1
D1
A2
B2
D2
A3
B3
D3
A4
B4
D4
A5
B5
D5
e1c, new
cell E
replace cell
B ,it has 32
NBs in its
neigbour
list
Truncated cell
below this
line could not
be added into
active set,
even those
NBs are
defined in the
RNC
A
E
D
A1
E1
D1
A2
E2
D2
A3
E3
D3
A4
E4
D4
A5
E5
D5
D6
…
…
D18
D18
Scenario:
•Intra-frequency
•No shared NB cell
exsiting
Only 5 NBs
with top
priority in the
defined NB
list of cell D
can be added
into new
monitored
list, big
problem!!!
AAL2 Failure
UE Issue
UE Frozen
No Acknowledge at Access
Preamble