W Paging Problem
W-Paging
Optimization Guide
www.huawei.com
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Foreword
z
Paging is associated with the paging success rate of the
network. It’s closely related to the whole network
performance. This KPI can be optimized by means of
“paging test” and the consequent trouble-shooting based on
paging failure analysis.
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page2
Learning Guide
z
Before learn this course, you should have:
‡
Learned WCDMA signaling flow
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page3
References
z
“WCDMA Signaling Flow”
z
“3GPP R7 25_series”
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page4
Objectives
z
Upon completion of this course, you will be able to:
‡
Collect data regarding paging problem
‡
Locate paging problem
‡
Solve the located paging problem
‡
Analyze the typical paging cases
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page5
Contents
1. Paging Overview
2. Paging Problem Analysis Process
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page6
Paging Initiation
z
CN initiated paging
z
z
Establish a signaling connection
UTRAN initiated paging
z
Trigger the cell update procedure
z
Trigger
gg reading
g of updated
p
system
y
information
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page7
Paging Type 1
z
If UE is in CELL_PCH,URA_PCH or IDLE state，the paging
message will be transmitted on PCCH with paging type 1
CN
RNC1
RNC2
NODEB1.1
NODEB2.1
PAGING
RANAP
RANAP
RANAP
PAGING
RANAP
PCCH: PAGING TYPE 1
PCCH: PAGING TYPE 1
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page8
UE
Paging Type 2
z
If UE is in CELL_DCH or CELL_FACH state，the paging
message will be transmitted on DCCH with paging type 2
CN
SRNC
UE
PAGING
RANAP
RANAP
DCCH: PAGING TYPE 2
RRC
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
RRC
Page9
Paging Overview
CN Initiated Paging UTRAN Initiated Paging
z
Paging Type 1 Applicable
Applicable
Paging Type 2
Applicable
Applicable
Paging type 2 could be considered as normal RRC signaling, no
more discussion about this part, for more detailed information,
please refer to the “WCDMA
WCDMA Signaling Procedure”
Procedure
z
Paging type 1 is the emphasis of this course
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page10
Contents
1. Paging Overview
2. Paging Problem Analysis Process
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page11
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization Target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page12
Flow for Analyzing Paging Problems
Collect network information
Identify optimization goal
Locate paging problem
Optimize paging problem
Optimization verification
NO
Optimization goal achieved?
YES
END
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page13
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page14
Network Information Collection Overview
z
Data of network to be optimized could be collected by the
following ways:
‡
Statistics
‡
Alarm
‡
Customers’ complaint
‡
Network planning info & optimization record
‡
Radio parameter configuration
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page15
Network Information Collection
z
Traffic statistics
‡
The paging-related traffic statistics can be observed
respectively on the traffic statistics console of RNC, UMSC and
SGSN according to different paging areas
‡
CN_PAGE_IDLE_UE_SUCC_RATE,, which is paging
p g g success
rate of UE in idle state initiated by CN
‡
UTRAN_PAGE1_SUCC_RATE, which is the success rate of
Paging Type 1 initiated by UTRAN
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page16
Network Information Collection
z
RNC Paging KPI
‡
CN_PAGE_IDLE_UE_SUCC_RATE =
[CN PAGE IDLE UE SUCC]/
[CN_PAGE_IDLE_UE_SUCC]/
[CN_PAGE_IDLE_UE_REQ]
‡
[[UTRAN_PAGE1_SUCC_RATE =
UTRAN_PAGE1_SUCC]/[UTRAN_PAGE1_REQ]
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page17
Network Information Collection
z
RNC Paging KPI
Name
Description
Standard measuring point
CN_PAGE_IDLE_UE_REQ
Count paging times at IU interface
of idle subscribers
Receive the PAGING messages initiated
byy CN when UE is in idle status
CN_PAGE_IDLE_UE_SUCC
Count paging success times of idle
subscribers
Receive RRC connection request
message of UE and the reason belongs to
the called type, such as “Terminating
Conversational Call”
UTRAN_PAGE1_REQ
Count times of initiating PAGING
TYPE 1 initiated from UTRAN side
PAGING TYPE 1 message initiated from
UTRAN side
UTRAN_PAGE1_SUCC
Count PAGING TYPE 1 message
initiated from UTRAN side and the
ti
times
off UE success receive
i
response received
UE paging response message received at
UTRAN side
id .
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page18
Network Information Collection
z
RNC counters for paging messages to idle UE
‡
Number of PAGING TYPE 1 messages from the RNC to the
UEs in idle mode after it receives the PAGING messages from
the CN
„
VS.RANAP.Paging.Att.IdleUE
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page19
Network Information Collection
z
RNC counters for successful paging messages to idle UE
‡
number of RRC CONNECTION REQUEST messages from the
UEs to the RNC that has sent a PAGING TYPE 1 messages to
page the UEs in idle mode
„
VS.RANAP.Paging.Succ.IdleUE
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page20
Network Information Collection
z
RNC counters for PAGING TYPE 1 message initiated from
UTRAN side
‡
number of PAGING TYPE 1 messages originated by the RNC
for triggering the state transition of an UE in CELL_PCH or
URA_PCH state
„
VS.UTRAN.Paging1.Att
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page21
Network Information Collection
z
RNC counters for successful PAGING TYPE 1 message
initiated from UTRAN side
‡
number of CELL UPDATE messages from the UEs to the RNC
‡
These messages are taken as successful responses to the
PAGING TYPE 1 messages sent by the RNC to the UEs in
CELL_PCH or URA_PCH state
„
VS.UTRAN.SuccPage1
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page22
Network Information Collection
z
UMSC Paging Traffic Statistics
LA paging success rate =
First paging transmission times－number of delivered no - response messages
First paging transmission times
First paging success rate =
First paging response times
First paging transmission times
Non - first paging success rate =
Interface paging repitetion response times
Interface paging repetition times
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page23
Network Information Collection
UMSC Paging Traffic Statistics
Index
Name
Description
Standard measure point
The first paging times
The first sending times of Paging
Req by MSC
Carry out statistics when MSC sends
PAGING message to RNC/BSC
The first paging response
times
Successfully receiving response
times after the first sending of
Paging message by MSC
Carry out statistics when MSC receives
PAGING RESPONSE after the first sending
of Paging message
Interface paging repeat times
The non-first paging times of MSC
Carry out statistics when MSC sends
PAGING message to RNC/BSC
Interface paging repeat
response times
Successfully receiving response
times after the non-first sending of
Paging message by MSC
Carry out statistics when MSC receives
PAGING RESPONSE after the non-first
sending Paging message
The first paging times of Iu
interface
The first sending Paging times of Iu
interface
Carry out statistics when MSC sends
PAGING message to RNC
Lu interface paging repeat
times
The non-first sending Paging times
of Iu interface
Carry out statistics when MSC sends
PAGING message to RNC not at the first
time
Delivery paging no-response
times
Times of having no paging
response messages received
Paging
g g timer stay-over
y
statistics
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page24
Network Information Collection
z
SGSN Paging Traffic Statistics
RAPagingSuccessRate＝
RAGroupPaging Re quesTimes－RAGroupPagingFailureTimes
RAGroupPaging Re questTimes
Name
Description
Standard measure point
Group paging
request times
of each RA
It provides delivery group
paging
i requestt times
ti
in
i th
the
specific RA, not including
retransmission messages
SGSN sends Iu interface paging
request message (PAGING), and
its CN Domain is PS.
pp
paging
g g
Group
failure times of
each RA
It provides group paging
failure times in the specific RA
Paging retransmission message
times reach maximum.
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page25
Network Information Collection
z
Alarm
‡
From CN
„
‡
RNC overload
From RNC
„
the flow control alarm
– When RNC is in paging flow control state, the paging message will be
lost unconditionally
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page26
Network Information Collection
z
Data collection from customers’ complaint
‡
Time
‡
Place
‡
Terminated UE type
‡
Others
„
Subscriber name
„
Originated phone number
„
Terminated phone number
„
Happened frequently or not
„
Process description
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page27
Network Information Collection
z
For the network that has not been put into service
‡
z
Pay more attention to the division of location area & route area
For the network that has been put into service, it may have
experienced several optimization processes before this
optimization. Emphasis should be put on optimization records
about:
‡
Coverage absence
‡
System overload
‡
Paging lost
‡
Low power allocation of paging channel
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page28
Network Information Collection
z
Parameters to be checked before optimization:
‡
CN paging retransmission times and paging interval
‡
UTRAN paging retransmission times and paging interval
‡
DRX paging cycle coefficient k (DRX paging cycle = 2k)
‡
Paging indication quantity NP included in a PICH frame
‡
Channel power allocation of PICH and PCH
‡
Whether CN adopts
p g
global p
paging
g g
‡
UE ID used by CN paging (IMSI,TMSI or PTMSI)
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page29
DRX Procedure
z
UE receives the paging indicator on PICH periodically, that
is the Discontinuous Reception (DRX)
z
The value for the DRX paging cycle length is determined as
follows: :
DRX Cycle Length ＝ MAX (2k, PBP) frames
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page30
Paging Indicator Channel (PICH)
z
Carrying Paging Indicators (PI)
z
Fixed rate (30kbps), SF = 256
z
N paging indicators {PI0, …, PIN-1} in each PICH frame, N=18, 36,
72
72, or 144
12 bits (undefined)
288 bits for paging indication
b0 b1
b 287 b 288
One radio frame ((10 ms))
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page31
b 299
Secondary Common Control Physical Channel
(SCCPCH)
z
Carrying FACH and PCH, SF = 256 - 4
‡
Pilot: used for demodulation
‡
TFCI: Transport Format Control Indication, used for describe data
fformatt
Data
TFCI
N TFCI bits
T slot = 2560 chips,
Slot #0
Pilot
N Pilot bits
N Data bits
Slot #1
20*2 k bits (k=0..6)
Slot #i
Slot #14
1 radio frame: T f = 10 ms
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page32
DRX Procedure (Cont.)
z
Through DRX, UE only listens to PICH at certain predefined
time. And UE will read the paging information on SCCPCH if
the paging indicator is 1.
z
The value of the Paging Occasion is determined as follows:
Paging Occasion (CELL SFN) =
{(IMSI div K) mod (DRX cycle length div PBP)} * PBP
+ n * DRX cycle length + Frame Offset
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page33
DRX Procedure (Cont.)
z
In FDD the UE shall monitor its paging indicator in the PICH
frame with SFN given by the Paging Occasion
z
The Page Indicator to use is calculated by using the
following formula:
PI = (IMSI div 8192) mod NP
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page34
Parameters of DRX
z
z
DRXCYCLELENCOEF
‡
Parameter name: DRX cycle length coefficient
‡
Recommended value: 6
PICHMODE
‡
Parameter name: PICH mode
‡
Recommended value: V36.
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page35
Parameters of DRX
z
MACCPAGEREPEAT
‡
Parameter name: Number of page re-TX
‡
Recommended value: 1
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page36
Common Physical
y
Channel Power Parameters
z
z
MAXTXPOWER
‡
Parameter name: Max transmit power of cell
‡
The recommended value is 430, namely 43dBm
PCPICHPOWER
‡
Parameter name: PCPICH transmit power
‡
The recommended value is 330
330, namely 33dBm
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page37
Common Physical
y
Channel Power Parameters
z
z
MAXFACHPOWER
‡
Parameter name: Max transmit power of FACH
‡
The recommended value is 10, namely 1dB
PCHPOWER
‡
Parameter name: PCH transmit power
‡
The recommended value is -20,
20 namely -2dB
2dB
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page38
Common Physical
y
Channel Power Parameters
z
PICHPOWEROFFSET
‡
Parameter name: PICH power offset
‡
The default value of this parameter is -7, namely -7dB
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page39
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page40
Optimization Target
z
Determining optimization KPI goal
‡
Two KPI, “location area paging success rate” and “RA paging
success rate” , should meet the optimization requirements. The
paging success rate is recommended to be higher than 86%
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page41
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page42
Paging Problem Allocating Overview
z
Paging problems can be divided into three categories:
‡
Paging message is not delivered at the air interface at all
‡
Paging message has been delivered, but UE does not receive
the message or receives the wrong message
‡
UE fails in responding after receiving paging messages
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page43
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page44
Paging Problem Optimization Overview
z
Further analysis on paging loss cause
‡
Too large paging area planned
‡
Improper setting of CN paging retransmission times and interval
‡
Improper setting of UTRAN paging retransmission times and interval
‡
CN adopts whole-network paging
‡
Improper setting of DRX paging cycle coefficient
‡
Improper setting of Np value
‡
CN adopts improper UE identifier
‡
Too low power allocation of paging channels
‡
Existence of coverage dead zones
‡
UE performance problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page45
Contents
2.5 Typical Paging Problem Analysis
2 5 1 Paging Area
2.5.1
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2 5 4 DRX Paging Cycle Coefficient and Np value
2.5.4
2.5.5 UE Identifier Utilized by CN Paging
2.5.6 Power allocation of Paging Channels
2.5.7 Coverage Dead Zones
2.5.8 UE Performance Problems and DETACH Functions
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page46
Paging Area Problem Analysis
z
In general, CN pages target UE in one paging area (LA or RA)
‡
‡
LA is defined for CS service paging
„
Mobile terminals can move freely without updating VLR
„
Contain one or more cells
RA is defined for PS service paging
„
Mobile terminals can move freely without updating SGSN in a
specified operation mode
„
z
A RA may contain one or more cells
LA ≥ RA
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page47
Paging Area Problem Analysis
z
Paging area is planned too large
‡
the same paging message of a network paging mobile station
may be sent in multi cells, which will overload the paging
channel as well as increasing signaling flow at the Iub interface
z
Paging area is planned too small
‡
subscribers will update locations frequently while moving,
which will increase signaling flow of the system. Moreover,
frequent location update will influence the standby time of UEs
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page48
Paging Area Problem Analysis (Cont.)
z
Calculaiton Result of Paging Area When Cn Id Adopting
IMSI :
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page49
Paging Area Problem Analysis (Cont.)
z
Optimization Measures
‡
Split location areas where network capacity or paging traffic is
bigger than a specified threshold, which can reduce paging
message flow efficiently
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page50
Contents
2.5 Typical Paging Problem Analysis
2 5 1 Paging Area
2.5.1
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2 5 4 DRX Paging Cycle Coefficient and Np value
2.5.4
2.5.5 UE Identifier Utilized by CN Paging
2.5.6 Power allocation of Paging Channels
2.5.7 Coverage Dead Zones
2.5.8 UE Performance Problems and DETACH Functions
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page51
Improper Setting of CN Paging retransmission
Times and Interval
z
In order to guarantee the paging success rate, CN will
retransmission paging message at the IU interface
‡
CN paging retransmission times and interval can be configured
‡
Paging is initiated specific to location area, paging
retransmission will increase paging traffic
‡
CN paging retransmission configuration should be in
accordance with UTRAN
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page52
Improper Setting of CN Paging retransmission
Times and Interval
z
Problem Analysis
‡
In order to guarantee the paging success rate, CN will
retransmission paging message at the IU interface
‡
CN paging retransmission is the retransmission paging in case
that UE has not responded at the first time
‡
It is no good for CN paging interval to be too short
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page53
Improper Setting of CN Paging retransmission
Times and Interval
z
Problem Analysis
‡
In order to guarantee the paging success rate, CN will
retransmission paging message at the IU interface
‡
CN paging retransmission is the retransmission paging in case
that UE has not responded at the first time
‡
It is no good for CN paging interval to be too short
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page54
Improper Setting of CN Paging retransmission
Times and Interval
z
Optimization Measures
‡
CN paging retransmission configuration should be in
accordance with UTRAN. When UTRAN retransmits paging
once it is suggested for CN configuration to retransmit once
once,
(totally twice) at the interval longer than two paging cycles
‡
Reduce paging repeat times and increase paging interval
interval, keep
the time of no paging responses unchanged, interval of
reporting prompt tones when there is no paging response will
not be influenced
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page55
Improper Setting of UTRAN Paging Retransmission
Times and Interval
z
Problem Analysis
‡
Paging is delivered at the fixed time (a paging cycle), and UTRAN
paging interval is the integer multiple of a paging cycle, one paging
cycle
y
in general
g
„
we can adjust UTRAN paging repeat interval by adjusting DRX paging
cycle coefficient k
z
Optimization Measures
‡
It is reasonable for paging retransmission times to keep the current
default configuration
‡
It is also reasonable to adjust paging retransmission times on RNC
maintenance console using MML command SET UDPUCFGDATA
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page56
Contents
2.5 Typical Paging Problem Analysis
2 5 1 Paging Area
2.5.1
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2 5 4 DRX Paging Cycle Coefficient and Np value
2.5.4
2.5.5 UE Identifier Utilized by CN Paging
2.5.6 Power allocation of Paging Channels
2.5.7 Coverage Dead Zones
2.5.8 UE Performance Problems and DETACH Functions
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page57
CN Whole Network Paging
g g Problem Analysis
y
z
Problem Analysis
‡
Considering improving call connection rate, CN side can be
configured with whole-network paging, which bears the characteristics
that paging has overridden the concept of location area
area, and is
initiated specific to all UTRANs suspended under whole CN
‡
In this case, paging traffic becomes larger, especially when multiple
location areas are suspended under CN, the location areas with
smaller capacity will be overloaded, and can not recover for a long
time
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page58
CN Whole Network Paging
g g Problem Analysis
y
z
Optimization measures
‡
Global paging should be avoided in CN
„
CN global paging is useful only when UE location area is recorded
as failure by NLR, which hardly occurs
„
once it occurs, it means serious fault occurs; even more CN global
paging
i d
does nott work
k
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page59
Contents
2.5 Typical Paging Problem Analysis
2 5 1 Paging Area
2.5.1
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2 5 4 DRX Paging Cycle Coefficient and Np value
2.5.4
2.5.5 UE Identifier Utilized by CN Paging
2.5.6 Power allocation of Paging Channels
2.5.7 Coverage Dead Zones
2.5.8 UE Performance Problems and DETACH Functions
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page60
Improper
p p Setting
g of DRX Paging
g g Cycle
y
Coefficient
z
DRX paging cycle coefficient of UE has CN-specific DRX and UTRAN-specific
DRX
CN
CN-specific
ifi DRX
UTRAN
UTRAN-specific
ifi DRX
SIB1
RRC CONNECTION
SETUP
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page61
Improper
p p Setting
g of DRX Paging
g g Cycle
y
Coefficient
z
DRX paging cycle coefficient
‡
‡
‡
‡
CN
CN-specific
ifi DRX cycle
l llength
th coefficient
ffi i t iis used
d ffor idl
idle mode
d
Minimum K value in CN-specific DRX cycle length coefficient and
UTRAN-specific DRX cycle length coefficient is used for connection
state ( CELL-PCH & URA-PCH )
CN-specific DRX cycle length coefficient is configured by command
“ADD
ADD CNDOMAIN”
CNDOMAIN for BSC6810 or “ADD
ADD UCNDOMAIN”
UCNDOMAIN for
BSC6900
UTRAN-specific DRX cycle length coefficient is configured by
command “SET
SET FRC
FRC” for BSC6810 or “SET
SET UFRC
UFRC” for BSC6900
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page62
Improper
p p Setting
g of DRX Paging
g g Cycle
y
Coefficient
z
Questions:
‡
Suppose that the CN paging repeat time is 1 (totally
broadcasting 2 times), and the interval is 2s, so how should the
UTRAN repeat times and the intervals be set?
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page63
Improper setting of Np value
z
Problem Analysis
‡
Np refers to PI paging indication number delivered in a certain frame by paging
indication channel PICH, the value of which is within the range of (18, 36, 72,
144), which is indicated by Number of PI per frame in SIB5, UE will receive
PICH frame at the specified paging time and find the corresponding PI
indicator bit (the qth PI). Only when the corresponding PI indicator bit is
effective, UE demodulates the corresponding S-CCPCH frame
⎛
Np ⎥ ⎞
⎢
q = ⎜⎜ PI + ⎢((18 × (SFN + ⎣SFN / 8⎦ + ⎣SFN / 64⎦ + ⎣SFN / 512⎦)) mod 144 ) ×
⎥ ⎟⎟ mod Np
144
⎣
⎦⎠
⎝
‡
Significance of Np in the actual network: IMSI is divided into Np groups by this
parameter, and all IMSIs in each group adopt the same PI
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page64
Improper setting of Np value
z
Influences of Np value on network
‡
If Np value is too small, the corresponding UE number in each group
will be larger. For each IMSI, if the probability that PI indication occurs
increases times that IMSI is waken up will increase
increases,
increase, which is no good
in saving UE power
‡
If Np value is too large, the corresponding IMSI number in each group
will be smaller. For each IMSI, if the probability that PI indication
occurs decreases, times that IMSI is waken up will decrease.
However if Np is larger
However,
larger, the bit number of each PI will decrease and
PICH demodulation performance of UE will be required higher
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page65
Contents
2.5 Typical Paging Problem Analysis
251 P
2.5.1
Paging
i A
Area
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2.5.4 DRX Paging Cycle Coefficient and Np value
2.5.5 UE Identifier Utilized by CN Paging
2 5 6 Att
2.5.6
Attach
h&D
Detach
t hS
Switch
it h S
Swtich
ti h
2.5.7 Power allocation of Paging Channels
2.5.8 Coverage Dead Zones
2.5.9 UE Performance Problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page66
UE Identifier Utilized by CN Paging
z
Problem Analysis
‡
When UE is in IDLE state, CN can only page 3 UEs at the same paging time
using IMSI
‡
When UE is in IDLE state, CN can only page 5 UEs at the same paging time
using TMSI or PTMSI
‡
When UE is in CELL_PCH or URA_PCH state, no matter what paging identifier
CN uses, UTRAN transfers UE identifier to U-RNTI and pages, it can only page
five UEs at the same paging time
z
Optimization Measures
‡
CN optimization
ti i ti pages b
by using
i UE ttemporary id
identifier
tifi TMSI and
d
PTMSI, and it can be adjusted with software parameters
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page67
Contents
2.5 Typical Paging Problem Analysis
251 P
2.5.1
Paging
i A
Area
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2.5.4 DRX Paging Cycle Coefficient and Np value
2.5.5 UE Identifier Utilized by CN Paging
2 5 6 Att
2.5.6
Attach
h&D
Detach
t hS
Switch
it h
2.5.7 Power allocation of Paging Channels
2.5.8 Coverage Dead Zones
2.5.9 UE Performance Problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page68
IMSI ATTACH & DETACH
F
Function
ti
z
Problem Analysis
‡
Aft UE iis powered
After
d on and
d registered
i t d successfully,
f ll MSC/VLR will
ill sett th
the
subscriber state as ATTACH state. IMSI DETACH means that after mobile
subscribers power off, MS initiates a DETACH flow and MSC/VLR sets the
subscriber state as IMSI detach
detach. Generally
Generally, HLR will not be informed by this
flow
‡
UE determines whether IMSI ATTACH and DETACH processes can be
adopted
d t d th
through
h receiving
i i th
the system
t
message 1
1. G
Gsm MAP IE consists
i t off
two octets, one is T3212, and bit1 of the other octet is ATT identifier. “0”
means that the network does not allow UE to adopt IMSI ATTACH and
DETACH processes, “1” refers
f
tto th
the admission
d i i
‡
During actual network operation, UTRAN should activate IMSI ATTACH and
DETACH functions
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page69
IMSI ATTACH & DETACH Function (Cont.)
(
)
z
SIB1
z
Optimization Measures
‡
Check and modify IMSI attachment and detachment admission indication by
using the Command “LST CNDOMAIN and MOD CNDOMAIN” on RNC
maintenance console
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page70
Contents
2.5 Typical Paging Problem Analysis
251 P
2.5.1
Paging
i A
Area
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2.5.4 DRX Paging Cycle Coefficient and Np value
2.5.5 UE Identifier Utilized by CN Paging
2 5 6 Att
2.5.6
Attach
h&D
Detach
t hS
Switch
it h
2.5.7 Power allocation of Paging Channels
2.5.8 Coverage Dead Zones
2.5.9 UE Performance Problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page71
Too Low Power allocation of
P i Ch
Paging
Channels
l
z
Phenomenon
‡
Subscriber complaints are centralized in some certain areas
‡
when UE is called, the prompt tone “the subscriber is out of
service” will occur
z
Problem Analysis
‡
the print message of paging decoding failure can be seen at
the UE daemon, which is the problem of the over-low paging
channel power allocation
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page72
Too Low Power allocation of
P i Ch
Paging
Channels
l
z
Optimization measures
‡
The current baseline power allocation: PICH is -3dB and PCH
is -2dB, which are both relative to pilot channels power.
‡
Improve the power allocation between PICH and PCH properly
‡
Check and modify PICH power by using MML Command LST
CHPWROFFSET and MOD PICHPWROFFSET on RNC
maintenance console
‡
Check and modify PCH power by using Command LST
SCCPCH and MOD SCCPCH
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page73
Contents
2.5 Typical Paging Problem Analysis
251 P
2.5.1
Paging
i A
Area
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2.5.4 DRX Paging Cycle Coefficient and Np value
2.5.5 UE Identifier Utilized by CN Paging
2 5 6 Att
2.5.6
Attach
h&D
Detach
t hS
Switch
it h
2.5.7 Power allocation of Paging Channels
2.5.8 Coverage Dead Zones
2.5.9 UE Performance Problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page74
Existence of Coverage Dead
Zones
z
Problem Analysis
‡
Phenomenon: Subscriber complaints are centralized in a certain area,
UE fails both in calling and being called, the signal strength shown in
UE panel is low
low, and RSCP and EC/IO of pilot signals tested with the
drive test equipment are lower than indexes required for UE normal
access, by which coverage dead zone is identified in this area
z
Optimization Measures
‡
Carry out coverage optimization, for specific optimization measures,
please refer to relevant Guidance
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page75
Contents
2.5 Typical Paging Problem Analysis
251 P
2.5.1
Paging
i A
Area
2.5.2 CN and UTRAN Paging retransmission Times and Interval
2.5.3 Whole-Network Paging strategy
2.5.4 DRX Paging Cycle Coefficient and Np value
2.5.5 UE Identifier Utilized by CN Paging
2 5 6 Att
2.5.6
Attach
h&D
Detach
t hS
Switch
it h
2.5.7 Power allocation of Paging Channels
2.5.8 Coverage Dead Zones
2.5.9 UE Performance Problems
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page76
UE Performance Problem
z
Problem Analysis
‡
‡
The receiving performance and demodulation performance of
different UEs are also different
Sort out and analyze subscriber complaint materials.
materials If the
called UE is of the same type, problem may exist in UEs
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page77
UE Performance Problem
z
Optimization Solution
‡
‡
Take a called verification test on UEs from different
manufacturers
compare UE receiving performance parameters and
demodulation performance parameters
„
including testing RSCP and EC/IO of pilot signals received at the
same place and learn about the service demodulation thresholds
of UEs
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page78
Contents
2. Paging Problem Analysis Process
2.1 Problem Analysis Flow
2.2 Network Information Collection
2.3 Optimization target Confirmation
2 4 Paging Problem Locating
2.4
2.5 Typical Paging Problem Analysis
2.6 Optimization Verification
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Page79
Optimization Verification
z
After network is optimized and adjusted, the optimization
results
lt should
h ld b
be verified.
ifi d Th
The ffrequently-used
tl
d verifying
if i
methods are available as follows:
‡
Traffic statistics
‡
Alarm
‡
Subscriber complaint
p
‡
Dialing test
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page80
Summary
z
We have learned the some typical cases of paging problem,
the paging problem could be caused by improper paging
area division, improper paging retransmission times and
interval, improper DRX paging cycle coefficient and Np
value, weak coverage, whether switch on attach/detach
f
function,
i
low
l
power allocation
ll
i off paging
i channels,
h
l and
d
specified UE performance.
Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Page81