OMF800603 Traffic Statistics Analysis ISSUE1.0
Transcript of OMF800603 Traffic Statistics Analysis ISSUE1.0
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Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Traffic Statistics Analysis
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Foreword
Traffic statistics is the performance of network.
Each traffic item is corresponding one feature of network.
Through the traffic statistics, can quickly settle the network problem.
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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
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Contents
1. Brief Introduction to BSC Traffic Statistics
2. Often-used Traffic Statistics Items Analysis
3. Locate Problem through Traffic Analysis
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Measurement term Counter WHAT
Normal counter : default counter + extended counter Customer counter
Object WHO Physical concept ( Board/Cabinet ) Logical concept ( BSC, Cell , TRX )
Period WHEN 5 , 15 , 30 , 60 , 1440 ( min )
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Hierarchical Structure of Performance
Unit m
Unit 1
Cluster 1
……
…
…Cluster n
Item 1
Item j
Item1
Item k
PERFORMANCE
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Hierarchical Structure of Performance
Cluster
Unit
Counter
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Contents
1. Brief Introduction to BSC Traffic Statistics
2. Often-used Traffic Statistics Items Analysis
3. Locate Problem through Traffic Analysis
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Analysis Process
Systematical logic:
From whole system to specific cell
Integrality
Observe the change trend of the items for more than
one week and the changing trend of each day.
Relativity
Relationship between various kinds of traffic statistics
items
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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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Analysis Process
There are 26 clusters in the BSC600
0 traffic statistics, 4 of them are imp
ortant for the optimization.
BSC Measurement
MR Measurement
Call Measurement
Channel Measurement
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Traffic Analysis
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Traffic Analysis
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Traffic Analysis
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Traffic Analysis
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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
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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
Outgoing inter-cell handover measurement per cell
Incoming inter-cell handover measurement per cell
Intra-cell Handover Measurement
Call drop measurement per cell
CPU usage measurement
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CPU Usage Measurement CPU measurement function includes two statistic items:
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
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CPU Usage Measurement
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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
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Interference Band Measurement Report
Interference Band Power Level Range
Interference band 1 –105 dBm to –98 dBm
Interference band 2 –98 dBm to –90 dBm
Interference band 3 –90 dBm to –87 dBm
Interference band 4 –87 dBm to –85 dBm
Interference band 5 –85 dBm to –47 dBm
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.
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Interference Band Measurement Report
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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
TCHF(H) Receive Level Measurement
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TCHF(H) Receive Level Measurement
Rank of Receive Level Receive Level(dBm)
0 <–100
1 (-100,85]
2 (-85,-80]
3 (-80,-75]
4 (-75,-70]
5 (-70,-65]
6 (-65,-60]
7 >-60
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TCHF(H) Receive Level Measurement
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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.
Neighbor Cell Level Measurement
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Neighbor Cell Level Measurement
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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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Outgoing Inter-cell Handover Measurement
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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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Incoming Inter-cell Handover Measurement
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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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Intra-cell Handover Measurement
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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 .
Uplink-and-Downlink Balance Measurement
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Uplink-and-Downlink Balance Measurement
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Uplink-and-Downlink Balance Measurement
Uplink-and-Downlink Balance Rank
Downlink Receive Level – Uplink Receive level – 6
1 –15 dB
2 –14 dB, –13 dB, –12 dB, –11 dB, –10 dB
3 –9 dB, –8 dB, –7 dB, –6 dB
4 –5 dB, –4 dB, –3 dB
5 –2 dB, –1dB, 0 dB
6 0 dB
7 1 dB, 2 dB
8 3 dB, 4 dB, 5 dB
9 6 dB, 7 dB, 8 dB, 9 dB
10 10 dB, 11 dB, 12 dB, 13 dB, 14 dB
11 15 dB, 16 dB, 17 dB, 18 dB, 19 dB, 20 dB
• Mapping between the uplink/downlink balance rank and the receive level.
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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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Power Control Messages
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Radio Link Failure Measurement Radio Link Failure Measurem
ent 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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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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Call Drop Measurement
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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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AMR Measurement
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Contents
1. Brief Introduction to BSC Traffic Statistics
2. Often-used Traffic Statistics Items Analysis
3. Locate Problem through Traffic Analysis
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Call Drop Analysis
High call drop cell
Radio link failureCall drop measurement
Rx-level
quality
TA
Call drop during the H.O
Call drop in stable state
drop due to the Abis interface
drop due to the equipment
drop due to forced H.O
alarm 、 hardware
Interference band
Up-down link balance
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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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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 s
mall TA. BQ call drop: high receiving signal strength and poor quality.
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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 new site to guarantee the effective continuous coverage; Add the necessary neighbor; Adjust antenna height and antenna downtilt, use high gain antenna; Modify some parameters
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Short Distance Call Drop
Causes : 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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Interference Call Drop Monitor and locate interference through some traffic statis
tics : Analysis interference band to monitor uplink interference, jud
ging 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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Interference Call Drop
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Interference Call Drop
Solutions : Drive test in the suspected area, check the receive leve
l 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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Up-down Link Balance Disposing method :
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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Handover Analysis Process
Low handover success rate
Alarm hardware
Interference band
Up-down link balance
Incoming H.O
Outgoing H.O
Neighbor cell level
KPI measurement
External inter-cellHandover
Internal inter-cellHandover
Intra cell H.O
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Handover Analysis
Find out the problem cells:
All cells or some cells
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 From “KPI measurement” and “External inter-cell handover”
“Internal inter-cell handover”, find out the cells which handover
success rate is lower
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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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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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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Summary
Traffic Statistics System Basics Key traffic Measurement Items Traffic Statistics Analysis Method
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