OMF800603 Traffic Statistics Analysis ISSUE1.0

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Traffic Statistics Analysis


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.


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


Contents

1. Brief Introduction to BSC Traffic Statistics

2. Often-used Traffic Statistics Items Analysis

3. Locate Problem through Traffic Analysis


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 ）


Hierarchical Structure of Performance

Unit m

Unit 1

Cluster 1

……

…

…Cluster n

Item 1

Item j

Item1

Item k

PERFORMANCE


Hierarchical Structure of Performance

Cluster

Unit

Counter


Contents





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


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.


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


Traffic Analysis


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


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


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


CPU Usage Measurement


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 Power Level Range

Interference band 1 –105 dBm to –98 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.


Interference Band Measurement Report


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



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


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


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.


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.


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.


Intra-cell Handover 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 .

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.


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.


Power Control Messages


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”


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


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.


AMR Measurement


Contents





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


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.


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.


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


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


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


Interference Call Drop


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.


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 .


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


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


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


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”


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.


Summary

Traffic Statistics System Basics Key traffic Measurement Items Traffic Statistics Analysis Method

Thank youwww.huawei.com

OMF800603 Traffic Statistics Analysis ISSUE1.0

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Transcript of OMF800603 Traffic Statistics Analysis ISSUE1.0