Embed Size (px)
DESCRIPTION
Owj104103 Wcdma Access Analysis Issue1.0
Citation preview
Wireless Curriculum Development SectionWireless Curriculum Development Section
ISSUEISSUE
WCDMA Access AnalysisWCDMA Access Analysis
1.01.0
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
2
Overview
Access is associated with the call setup success
rate of the network. This KPI can be optimized by
means of “Call setup test” and the consequent
trouble-shooting based on access failure analysis.
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
3
Objectives
Be familiar with the access procedure in UMTS
Do analysis on access problems independently
When finished this course,you will be able to:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
4
Course Contents
Definition of access failure
Access problem analysis process
Common reasons for access problems
Case study
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
5
Definition of access failure
General originating call setup signaling flow:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
6
Definition of access failure
General terminating call setup signaling flow:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
7
Definition of access failure
Call setup succeeds when the call setup phase is
completed (when CC Connect is received). If the
call fails to reach the CC Connect stage, it should be
pegged as an access failure .
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
8
Course Contents
Definition of access failure
Access problem analysis process
Common reasons for access problems
Case study
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
9
Access problem analysis process
Preparation before AnalysisPreparation before Analysis
Access problem analysis
methods
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
10
Preparation before analysis
Be familiar with the planning information which can be obtained from planning reports;
Be familiar with history records of optimization;
Get the latest reliable summary sheet of the engineering parameters;
Get the latest configuration of radio parameters;
Obtain the network traffic statistics and the subscriber complaint information of access.
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
11
Access problem analysis process
Preparation before Analysis
Access problem analysis Access problem analysis
methodsmethods
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
12
Access problem analysis methodsGeneral methods of access problem analysis:
Traffic statistics data analysisCustom complaint collection
Call setup test in specific area
Coverage analysis
Signaling analysis
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
13
Access problem analysis methods
Traffic statistics data and custom complaint collection reveal problems exactly, further trouble-shooting can be carried out by call setup test. While for a pre-commercial or trial network, call setup test is the effective way.
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
14
Course Contents
Definition of access failure
Access problem analysis process
Common reasons for access problems
Case study
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
15
Common reasons for access problems
RF reasonsRF reasons
Radio Parameter Settings
Other reasons
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
16
RF reasons
Poor coverage
Strong Uplink or downlink Interference
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
17
Common reasons for access problems
RF reasons
Radio Parameter SettingsRadio Parameter Settings
Other reasons
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
18
Radio parameter settings
Improper threshold of Qqualmin and Qrxlevmin Improper settings of access threshold Inappropriate settings of preamble power ramp step and ret
ransmission times Inappropriate setting of adjacent cells Inappropriate setting of synchronization parameters Unsuitable power allocation rate for common channel Unsuitable initial power of uplink and downlink dedicated ch
annel Unsuitable setting of uplink Initial SIR target value of dedica
ted channel
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
19
Common reasons for access problems
RF reasons
Radio Parameter Settings
Other reasonsOther reasons
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
20
Other reasons
Data configuration problems
Access problems caused by cell load
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
21
Course Contents
Definition of access failure
Access problem analysis process
Common reasons for access problems
Case study
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
22
Case study
Access failure due to synchroni-Access failure due to synchroni-
zation failurezation failure
Access failure during RB setup
Access failure during handover
process
Access failure due to terminating
UE
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
23
Access failure due to synchronization failure
Access failure location:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
24
Access failure due to synchronization failure
UE Txpower reaches maximum value 21 dBm during VP call setup. So this call setup failure may be caused by Uplink synchronization failure:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
25
Access failure due to synchronization failure
UE does not send RRC Connection Setup Complete to RNC after receiving RRC Connection Setup message from RNC :
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
26
Case study
Access failure due to synchroni-
zation failure
Access failure during RB setupAccess failure during RB setup
Access failure during handover
process
Access failure due to terminating
UE
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
27
Access failure during RB setup
Access failure location:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
28
Access failure during RB setup
UE Tx power is very low and downlink pilot Ec is high before access failure,but Ec/Io is not very good :
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
29
Access failure during RB setup
The cause of call setup failure is Requested circuit/channel not available:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
30
Access failure during RB setup
RNC didn’t receive
RB Setup Complete
message after it has
sent RB Setup
message to UE.
Timeout of RNC is
reached after 1.5s:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
31
Case study
Access failure due to synchroni-
zation failure
Access failure during RB setup
Access failure during handover Access failure during handover
process process
Access failure due to terminating
UE
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
32
Access failure during handover process
Access failure location (Scanner Rscp ):
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
33
Access failure during handover process
ScannerEc/I0 :
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
34
Access failure during handover process
Scanner BestServer :
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
35
Access failure during handover process
During access process, UE Txpower is rising rapidly :
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
36
Access failure during handover process
And the downlink Bler reaches 100%:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
37
Access failure during handover process
UE report the measurement of cell Sc508 which request the
active set update:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
38
Access failure during handover process
The report was
received properly
and
“RRC_ACTIVE_UPD
ATE” was sent as
response while UE
didn’t received it
which results in the
access failure:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
39
Access failure during handover process
Let’s turn to the performance of the terminating UE. During the access process, the measurements from the terminating UE were not satisfactory either:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
40
Access failure during handover process
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
41
Access failure during handover process
While the
radio links hold
on till successful
handover is
completed:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
42
Access failure during handover process
Then the originating UE loses connection to the network and access released where the cause is “destination out of order” from the signal traced by the terminating UE:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
43
Case study
Access failure due to synchroni-
zation failure
Access failure during RB setup
Access failure during handover
process
Access failure due to terminating Access failure due to terminating
UEUE
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
44
Access failure due to terminating UE
Access failure location (UE Ec/I0 ):
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
45
Access failure due to terminating UE
The coverage is not bad where the UE originates the VP access:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
46
Access failure due to terminating UE
CN send “disconnect” message with the cause “bearer capability not authorized” before access failure:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
47
Access failure due to terminating UE
setup signaling procedure for RRC and RAB have already finished. The cause of disconnect is the same:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
48
Access failure due to terminating UE
The reason is: we use two mobile to test video phone, for the originating call mobile camped in 3G network, but the terminating call mobile camped in 2G network that moment, so video call setup failed, the missing signaling of terminating UE can also explain it:
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
49
Summary
Access process is complicated since different devices are
involved and scenario varies. Careful study from signal
distribution to signaling procedure makes things easy.
Examples above are derived from tests carried out before,
which give general idea of trouble shooting, advanced
researches will be supplemented. .
Confidential Information of Huawei. No Spreading without Permission.
Security Level: Internal
50
