2G Traffic Statistics Analysis ISSUE1.0
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2G Traffic Statistics Analysis ISSUE1.0
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Traffic Statistics Analysis
Foreword
Each traffic item is corresponding one feature of network.
Through the traffic statistics, can quickly settle the network
problem.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights
reserved.
Objectives
Upon completion of this course, you will be able to:
Know the traffic statistics system structure of BSC6000
Understand some often-used traffic measurement items
Locate some problems through the traffic statistics system
Copyright © 2008 Huawei Technologies Co., Ltd. All rights
reserved.
Contents
Often-used Traffic Statistics Items Analysis
Locate Problem through Traffic Analysis
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reserved.
Measurement term
Counter WHAT
Customer counter
Object WHO
Period WHEN
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reserved.
Hierarchical Structure of Performance
Hierarchical Structure of Performance
Contents
Often-used Traffic Statistics Items Analysis
Locate Problem through Traffic Analysis
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reserved.
Analysis Process
Systematical logic:
Integrality
Observe the change trend of the items for more than one week and
the changing trend of each day.
Relativity
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reserved.
Analysis Process
Analysis process
First we shall analyze and compare the item of BSC measurement
function to have a rough idea for the whole network.
During analyzing, if any important items (such as call drop rate or
handover success rate) are abnormal, we shall do further detailed
analysis for the corresponding items.
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reserved.
Analysis Process
There are 26 clusters in the BSC6000 traffic statistics, 4 of them
are important for the optimization.
BSC Measurement
MR Measurement
Call Measurement
Channel Measurement
Traffic Analysis
The statistic items in BSC Measurement Function are used to measure
the traffic volume of all the cells in the BSC, including the call
drop, handover and assignment.
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reserved.
Traffic Analysis
MR measurement is some items about measurement report ,helping the
user to optimization.
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reserved.
Traffic Analysis
Call measurement is the performance during the calling, such as
Handover, call drop and assignment; measurement object includes
cell, TRX and the LAPD link
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reserved.
Traffic Analysis
Channel measurement is about the channel allocated, channel
conversion and the channel load
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reserved.
Often-used Items
In BSC6000, there are some traffic units are important for the
analysis of interference, call drop and handover, more attention
should be paid on those
Interference band measurement report per TRX
Power control messages per cell
Neighbor cell level measurement per cell
Uplink-and-downlink balance measurement per TRX
Radio link failure measurement per TRX
TCHF(H) receive level measurement per TRX
Copyright © 2008 Huawei Technologies Co., Ltd. All rights
reserved.
Often-used Items
In BSC6000, there are some traffic units are important for the
analysis of interference, call drop and handover, more attention
should be paid on those
KPI measurement per cell
Intra-cell Handover Measurement
CPU usage measurement
CPU Usage Measurement
Percentage of CPU occupation (%)
Peak percentage of CPU occupation (%)
The former one is the percentage of CPU in busy status during the
measurement cycle. This item indicates the load of BSC. The latter
one is the maximum CPU occupation within measurement cycle
It is recommended to register this task on any occasion
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reserved.
CPU Usage Measurement
Copyright © 2008 Huawei Technologies Co., Ltd. All rights
reserved.
KPI measurement is about the traffic statistics of each cell, it
includes all the important items, helping the engineer analyze each
cell performance
KPI Measurement
Interference Band Measurement Report
Interference band is the interference level contained in the RF RES
IND message that the BTS reports to the BSC when the channel is
idle. There are five levels. The level range of each band is set
through the LMT. The higher rank suggests higher interference
level. An idle channel at interference band 4 or 5 suggests the
existence of interference.
Interference Band
Interference band 2
Interference band 3
Interference band 4
Interference band 5
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reserved.
Interference Band Measurement Report
TCHF(H) Receive Level Measurement
The valid MRs that the BSC receives contain the ranks of the uplink
and downlink receive level and the ranks of the uplink and downlink
receive quality
The receive level has eight ranks, and higher rank suggests greater
receive level
The receive quality has eight ranks, and higher rank suggests worse
receive quality
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reserved.
TCHF(H) Receive Level Measurement
Rank of Receive Level
TCHF(H) Receive Level Measurement
Neighbor Cell Level Measurement
Neighbor Cell Level Measurement per Cell refers to the measurement
of mean receive level of neighbor cells. This measurement unit
helps to determine whether to configure neighbor cells.
If “Number of MRs of Neighbor Cells” and “Strength of Signals in
Neighbor Cells” are higher ,this cell should be configured as
neighbor cell.
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reserved.
Neighbor Cell Level Measurement
Outgoing Inter-cell Handover Measurement
This measurement refers to performance of MS handover from target
cell to the each neighbor cell, including Handover request times,
handover success times, radio handover success rate
It also record the handover reason, such as receive level , bad
quality, better cell, TA, receive level drop, enhance dual band
cell.
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reserved.
Outgoing Inter-cell Handover Measurement
Incoming Inter-cell Handover Measurement
This measurement refers to performance of MS handover from each
neighbor cell to this serving cell, including Handover request
times, handover success times, radio handover success rate
From the incoming inter-cell handover measurement, can locate the
neighbor cell which handover to this cell is not good.
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reserved.
Incoming Inter-cell Handover Measurement
Intra-cell Handover Measurement
It measures the intra-cell handover request times, success
times.
This traffic unit also measure the reasons of intra-cell handover:
interference intra-cell handover, TCHF-TCHH in the AMR calling,
intra-cell handover during the channel conversion,
overlaid/underlaid handover.
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reserved.
Intra-cell Handover Measurement
Uplink-and-Downlink Balance Measurement
Proper power estimation during network planning is a prerequisite
for normal operation of the system. The uplink and downlink signals
in the coverage area must be balanced.
The MR that the BSC receives contains the uplink receive level and
the downlink receive level. The uplink and downlink balance level
is determined by the following formula: Downlink receive level –
uplink receive level – 6 .
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reserved.
Uplink-and-Downlink Balance Measurement
Uplink-and-Downlink Balance Measurement
Mapping between the uplink/downlink balance rank and the receive
level.
Uplink-and-Downlink Balance Rank
1
–14 dB, –13 dB, –12 dB, –11 dB, –10 dB
3
4
5
6
9
10
10 dB, 11 dB, 12 dB, 13 dB, 14 dB
11
15 dB, 16 dB, 17 dB, 18 dB, 19 dB, 20 dB
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reserved.
Power Control Messages
Power Control Messages per Cell refers to the measurement of the
transmission power and the receive level between the BTS and the
MS. It can measure the coverage of cell and the receive level or
quality average.
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reserved.
Power Control Messages
Radio Link Failure Measurement
Radio Link Failure Measurement per TRX refers to the measurement of
level, quality, and TA in the MR during call drops. From this unit
can check is there any interference or coverage too low. Judge the
call drop position from “Radio link failure measurement based on
TA”
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reserved.
Call Drop Measurement
Call drop measurement classify all the call drop by reasons and the
channel type
According this traffic , can get the detail reason of call drop
,helping locate the call drop problem
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reserved.
Call Drop Measurement
AMR Measurement
The BSC measures these counters when receiving the SETUP or CALL
CONFIRMED message that contains the speech version.
It indicates penetration of AMR MS.
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reserved.
AMR Measurement
Contents
Often-used Traffic Statistics Items Analysis
Locate Problem through Traffic Analysis
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reserved.
Call Drop Analysis
drop due to the Abis interface
drop due to the equipment
drop due to forced H.O
alarmhardware
Interference band
Up-down link balance
Find out the high call drop rate cell in the “KPI
measurement”
Check those cell’s traffic and the call drop times, exclude the low
traffic high call drop rate cell
Find out the call drop reason in “call drop measurement ”
Check the receive level ,quality and the TA in “radio link failure
measurement”
“Interference band” “Up-down link balance “ and the alarm system
also will help to locate the high call drop reason
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reserved.
Call Drop Analysis
Call drop in stable state: call drop during the calling, the major
reasons are “error indication” and “connect failure”.
Call drop in handover state: call drop during handover, in other
word , handover failure and reset-up also failure.
Call drop due to Abis terrestrial link failure: normally the reason
is Abis transmission, also can check alarm system to find out this
problem.
Call drop due to equipment failure: the call drop reason is related
to hardware fault.
Call drop due to force handover: during the calling, system force
the MS handover and handover failure , call drop occur.
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reserved.
Radio Link Failure Measurement
Check receive level, quality and TA in “radio link failure
measurement” to analysis the call drop type:
Edge call drop: low receiving signaling strength, large TA.
Short distance call drop: low receiving signal strength and small
TA.
BQ call drop: high receiving signal strength and poor
quality.
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reserved.
Edge Call Drop
Causes
MS is out of cell’s effective coverage area, “Island” phenomenon
caused by over shooting or missing neighbor, Isolated site.
Solutions
Add the necessary neighbor;
Adjust antenna height and antenna downtilt, use high gain
antenna;
Modify some parameters
Modify some parameters: “SACCH multi-frames”, “Radio link timeout
counter”, “handover threshold”, “handover statistic time”,
etc
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reserved.
Short Distance Call Drop
Poor coverage caused by complicated terrain or high dense
building
Solutions
Increase EIRP
Adjust antenna direction and downtilt, make the main lobe point to
high traffic area
Adjust parameters related to call drop
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reserved.
Interference Call Drop
Analysis interference band to monitor uplink interference, judging
inter network or intra network interference according the
relationship between interference and traffic
Monitor uplink and downlink interference via “TCHF(H) receive level
measurement”. If most M.R receive level high and the quality bad,
the interference will be serious
In “BTS maintenance”-”maintain cell”-”configure frequency scan” ,
can monitor which frequency is interfered
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reserved.
Interference Call Drop
Interference Call Drop
Solutions
Drive test in the suspected area, check the receive level and the
quality; using the spectrum equipment to find out the interference
resource.
Active frequency hopping, DTX and the Power control to reduce the
interference.
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reserved.
Up-down Link Balance
Analyze “up-down link balance measurement function” statistics
result and confirm whether the uplink and downlink are
balanced.
In call drop measurement function, analyze the average receiving
signal strength and quality for both the uplink and downlink
.
In power control measurement function, analyze the average
receiving signal strength for both the uplink and downlink .
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reserved.
Handover Analysis Process
Handover Analysis
Handover problem direction:
Outgoing or incoming
Handover failure object:
Handover to all the neighbor cells or just handover to certain cell
has problem
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Handover Analysis
Analysis the major handover failure is in outgoing or
incoming
Check “Incoming and outgoing handover measurement” to find out it
is just related to certain cell or to all the neighbor cells
From “neighbor cell revel” to decide deleting or adding neighbor
cell
Check “Intra-cell handover measurement” to monitor AMR,
overlaid/underlaid performance
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reserved.
Handover Analysis
Monitor transmission and board alarms
Analysis “Up-down link balance measurement” to make sure that cell
unbalance or not
Interference also will make the handover success rate lower, so
should pay more attend to “interference band” “TCHF(TCHH) receive
level measurement”
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reserved.
Handover Parameters
Locate and solution
Check whether the handover threshold such as TA, BQ and handover
function switch are suitable or not.
Check whether the successful TCH seizures for handover are much
more than successful TCH seizures for call. If handover times
divided by call times is larger than 3, then it indicates that
there may be ping-pong handover. Check the parameter settings and
adjust them (layer setting, layer handover hysteresis, inter cell
handover hysteresis, PBGT threshold, etc.).
Check whether the average signal strength is low when the handover
happens. If so, it indicates the edge handover threshold is too
low.
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reserved.
Summary