GSM RF Optimization
Short Description
Download GSM RF Optimization...
Description
2007.10.01
Confidential: Internal Open
GSM RF Optimization Basic Wang Song GSM RNP Post-sale TS
www.huawei.com
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of Optimization KPI of radio network Work flow of Optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 2
EtisalatMisr TK Project RNP Team Training
Concept of Optimization
Radio network optimization means network performance improvement utilizing existing network resources. Steps in general Data collection and verification Data analysis Parameter and hardware adjustment Optimization result confirm and reporting The purpose is increasing the utilization of network resources and solving the existing and potential problem on the network, identifying solutions for future network planning.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 3
EtisalatMisr TK Project RNP Team Training
Concept of Optimization
Capacity
Quality
Coverage
Optimize HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 4
EtisalatMisr TK Project RNP Team Training
Concept of Optimization
Due to the mobility of subscribers and complexity of radio wave propagation, most of network problems are caused by increasing subscribers and the changing environments. Optimization is a continuous process that is required as the network evolves
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 5
EtisalatMisr TK Project RNP Team Training
Concept of Optimization
In the following case, the network should be optimized New network or expansion on existing network The network quality decreased seriously and there are many complaints from subscribers. An event occurs suddenly which affects the network performance seriously. The number of subscribers increased and affects the network performance gradually.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 6
EtisalatMisr TK Project RNP Team Training
Concept of Optimization • Input for Optimization
CUSTOMER COMPLAINTS
OPTIMIZE TRAFFIC STATISTICS
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
DRIVE TEST
Page 7
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of optimization KPI of radio network Work flow of Optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 8
EtisalatMisr TK Project RNP Team Training
KPI of Radio Network
KPI (KEY PERFORMANCE INDICATORS) Indicates overall performance of network over a period of time Good way to monitor network trends and anticipate future problems Data obtained from drive test and traffic statistics
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 9
EtisalatMisr TK Project RNP Team Training
KPI of Radio Network Typical Radio Network KPI KPI Parameter
Source
Call Drop Rate
Stat. & DT
Congestion Rate
Stat.
Handover Success Rate
Stat. & DT
Busy Hour Traffic
Stat.
TCH Utilization
Stat. & Alarms
Call Setup success rate
Stat. & DT
Coverage
DT
Quality
DT
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
BTS1
BTS3
BTS4
Page 10
BTS2
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of optimization KPI of radio network Work flow of optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 11
EtisalatMisr TK Project RNP Team Training
Flow Chart of Network Optimization
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 12
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of Optimization KPI of radio network Work flow of Optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 13
EtisalatMisr TK Project RNP Team Training
Parameter Adjustment Principles •Parameter adjustment procedure
MONITOR EFFECT
IDENTIFY PROBLEM
MAKE MAKE CHANGES CHANGES HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 14
EtisalatMisr TK Project RNP Team Training
Parameter Adjustment Principles •Parameter Types
Radio Parameters Engineering Parameters Antenna
SI Parameters Handover Parameters
D-tilt CC&PWC Parameters
HUAWEI TECHNOLOGIES Co., Ltd.
Antenna
Antenna
Height
Orientation
HUAWEI Confidential
Page 15
EtisalatMisr TK Project RNP Team Training
Parameter Adjustment Principles Adjustment of cell data parameters
Adjust the cell parameters according to the features of actual radio channel traffic and signaling load. The parameters are for cell select,cell reselect,call setup, handover etc, so as to improve the overall network performance and service quality to the end user. Another basic principle of radio parameter adjustment is to maximize the current network resource, traffic sharing in the the whole network, increase the utilization of the equipment, so as to increase the profit-investment ratio.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 16
EtisalatMisr TK Project RNP Team Training
Parameter Adjustment Principles
According to the feature of problem to be solved, there are two types of radio parameter adjustment. Solve static problems: Analyze the average traffic and signaling flows of the network and solve the network problems that existed long time Solve traffic overload and congestion problems during some special period caused by special events.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 17
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of Optimization KPI of radio network Work flow of Optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 18
EtisalatMisr TK Project RNP Team Training
Driving Test Tools
The following are the frequently used drive test tools:
Genex Probe and Assistant TEMS Ant Pilot and Ant
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 19
EtisalatMisr TK Project RNP Team Training
Driving Test Tools Drive test Tool application:
Identify specific problems in the network Attend to customer complaints Perform network benchmarking with other operators Collect periodic network data for reporting Check coverage in new areas
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 20
EtisalatMisr TK Project RNP Team Training
Driving Test Tools Example: Drive test data
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 21
EtisalatMisr TK Project RNP Team Training
Signaling Analyzer Signaling Trace
In BSC6000 LMT, Interface signaling trace support: A: BSSAP SCCP MTP3 MTP2 Abis: RSL OML LAPD Pb: Application LAPD Um Single User Other equipment : MA10 , K15 Signaling Analyze Huawei MAINEX: Signal Analyze Tool
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 22
EtisalatMisr TK Project RNP Team Training
Spectrum Analyzer Scaner (Spectrum analyzer)
The spectrum analyzer is mainly used to test the characteristics of frequency, including spectrum, power of the adjacent channel, and frequency scanning etc.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 23
YBT250
EtisalatMisr TK Project RNP Team Training
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 24
OMC
EtisalatMisr TK Project RNP Team Training
Huawei Wireless System OMC is M2000 Provides flexible means to record different information from the network: Config /Alarms /Stats. Able to sample large amounts of data to give a better picture of the network on a longer period of time
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 25
EtisalatMisr TK Project RNP Team Training
OMC Traffic Statistics
BSC performance measurement functions High drop High block
List of alarm
rate
rate Drop call
Rx_q & Rx_l measure
measure
TCH
Drop
statistics
measure
Low HO suc rate
List of alarm
Hardware Conk out
Rx_q & Rx_l
balance between UL
measure
& DL
List of alarm
HO
TCH
measurement
statistics Incoming cell HO Outgoing cell HO
Signalling test HUAWEI TECHNOLOGIES Co., Ltd.
List of alarm
instrument
HUAWEI Confidential
Page 26
EtisalatMisr TK Project RNP Team Training
Measurement Units Related to Call 1
Immediate Assignment Measurement per Cell
11Intra-Cell Handover Measurement per Cell
2
Assignment Measurement per Cell
12Incoming Internal Inter-Cell Handover Measurement per Cell
3
Call Drop Measurement per Cell
13Outgoing Internal Inter-Cell Handover Measurement per Cell
4
Short Message Measurement per Cell
14Incoming External Inter-Cell Handover Measurement per Cell
5
Channel Activation Measurement per Cell
15Outgoing External Inter-Cell Handover Measurement per Cell
6
Flow Control Measurement per Cell
16Incoming Inter-RAT Inter-Cell Handover Measurement per Cell
7
KPI Measurement per Cell
17Outgoing Inter-RAT Inter-Cell Handover Measurement per Cell
8
Channel Seizure Measurement per TRX
18GSM Cell to GSM Cell Incoming Handover Measurement
9
Calls Discarded due to Overload per LAPD
19GSM Cell to GSM Cell Outgoing Handover Measurement
Call Duration Measurement per BSC
20Measurement of MRs upon Handover Initiation per Cell
10
The counters measured in such flows as immediate assignment, assignment, and handover during call can reflect the operation of the traffic of BSC.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 27
EtisalatMisr TK Project RNP Team Training
Measurement Units Related to MR 1Number of MRs per Cell
Cell
2Power Control Messages per Cell 3Neighbor Cell Level Measurement per Cell 4Interface Band Measurement per TRX 5TCHF Receive Level Measurement per TRX 6TCHH Receive Level Measurement per TRX 7Receive Quality Measurement per TRX
TRX
8Uplink-and-Downlink Balance Measurement per TRX 9Number of MRs based on TA per TRX 10Radio Link Failure Measurement per TRX 11Radio Link Failure Measurement based on TA per TRX
12RQI Measurement based on TA per TRX
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
After occupying a dedicated channel, MS will report measurement reports periodically. BSC performs power decisions and handover decisions according to the reported measurement reports. The units listed in the left table are used to measure the counters related to measurement reports and help the users to analyze and optimize the network performance.
Page 28
EtisalatMisr TK Project RNP Team Training
Measurements Related to Channel 1
Channel Configuration Measurement per Cell
2
Channel Conversion Measurement per Cell
3
Channel Busy Duration Measurement per Cell
4
Measurement of Maximum Busy Channels per Cell
5
Channel State Measurement per Cell
6
Channel Assignment Request Measurement per Cell
7
Channel Assignment Failure Measurement per Cell
8
Channel Assignment Concentric Cell Measurement per Cell
9
Channel Assignment Queue Measurement per Cell
10
Channel Assignment GPRS Measurement per Cell
11
Channel Assignment Success Measurement per TRX
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
During operation, BSC performs dynamic adjustment to such channel resources as TCH, SDCCH, and PDCH to optimize the utilization of resources. At the same time, the system is required to regularly output the statistic about the state of the channels, such as busy, idle, or blocked. The previous data is very useful for you to learn about the operation condition of the system and the distribution condition of the traffic.
Page 29
EtisalatMisr TK Project RNP Team Training
Course Contents
Concept of Optimization KPI of radio network Work flow of Optimization Parameter adjustment principles Optimization tools introduction Common problems of Optimization HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 30
EtisalatMisr TK Project RNP Team Training
Common Problems of Optimization The three most important performance criteria are coverage, capacity and quality. they mainly correspond to the following network problems: Coverage Congestion Interference Handover TCH call drop Dual-band or Dual-System Traffic Distribution
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 31
EtisalatMisr TK Project RNP Team Training
Common Problems --Coverage Coverage Gap
Coverage hole may exist when coverage areas of two BTS do not overlap or there are some big obstacles in the coverage area, this lead to no signal or very poor signal level. Over shooting In the actual network, the high BTS antenna can propagate far away along a road and serve in area which it’s not suppose to serve in; which result in the "isolate Island" problem.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 32
EtisalatMisr TK Project RNP Team Training
Common Problems --Coverage Check and solve the coverage problem:
Power control measurement Function ( Statistics) Receiving Level Measurement Function ( Statistics) Cell Measurement Function ( Statistics) Inter-cell Handover Measurement Function ( Statistics)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 33
EtisalatMisr TK Project RNP Team Training
Common Problems --Coverage Check the coverage problem:
Call Drop Measurement Function ( Statistics) Adjacent Measurement Function (Statistics) Outgoing Inter Cell Handover Measurement Function ( Statistics) Rx Level data ( Drive test)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 34
EtisalatMisr TK Project RNP Team Training
Common Problems --Coverage Coverage Problem Solution:
Adjust Radio parameters Adjust antenna parameters Use booster, low loss combiner and tower mount amplifier Add new site (last resort)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 35
EtisalatMisr TK Project RNP Team Training
Common Problems --Capacity Capacity
TCH congestion Check TCH congestion rate: attempted TCH seizers failure for all (no radio resource available ) on OMC traffic statistics data, or compare the busy hour traffic of each cell with the calculated capacity in different GoS to judge the situation of traffic congestion .
Traffic balance Adjust the antenna height, downtilt, and change the TX power of BTS and MS. Adjust parameters for cell selection, cell reselection and handover Enable load handover and direct retry functions.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 36
EtisalatMisr TK Project RNP Team Training
Common Problems --Interference How to locate the interference
Interference band in TCH Measurement Function ( Statistics) Receiving Level Measurement Function ( Statistics) Rx_Qual ( Drive test) Uplink Frequency Scan in LMT Scaner (YBT250)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 37
EtisalatMisr TK Project RNP Team Training
Common Problems --Interference How to locate the interference
Ratio of handovers for uplink/downlink quality ( Statistics) Receiving Quality Measurement (Statistics) Call drop measurement function ( Statistics) Too many handover failure and reestablishment failures ( Statistics)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 38
EtisalatMisr TK Project RNP Team Training
Common Problems --Interference Check and solve the interference problems
Check the place with interference and conversation quality by drive test. Use spectrum analyzer to find out the interference in the frequency band. Enable frequency hopping, DTX and power control functions. Check and eliminate equipment problems (if any).
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 39
EtisalatMisr TK Project RNP Team Training
Common Problems --Interference Means to decrease the interference :
Increase the reuse distance between the cofrequency and adjacent frequencies. Decrease the transmitting power of BTS. Adjust the antenna height, azimuth, down-tilt. Use the anti-interference technologies, such as frequency hopping, power control, DTX, and so on.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 40
EtisalatMisr TK Project RNP Team Training
Common Problems --Handover Common handover problems:
Handover failure and handover delay lead to bad quality or call drop. Frequent handover decreases the conversation quality and increases system signaling load. Unreasonable proportion of outgoing inter-cell handover to incoming inter-cell handover results in imbalanced traffic.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 41
EtisalatMisr TK Project RNP Team Training
Common Problems --Handover Check and solve handover problems:
Check the handover parameters (OMC) Inter-cell Handover Measurement Function (Statistics) Undefined Adjacent Cell Measurement Function (Statistics) Outgoing Inter Cell Handover Measurement Function (Statistics) Incoming Inter Cell Handover Measurement Function (Statistics) TCH Measurement Function (Statistics)
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 42
EtisalatMisr TK Project RNP Team Training
Common Problems --Handover Causes of abnormal handover and solutions:
The outgoing inter cell handover threshold is too low. The adjacent cells is congested. There are undefined adjacent cells relationship. The handover hysteresis and handover priority are not reasonable. The handover statistics times N and P are not set reasonable. In HCS network coexisting with other vendor’s cells, the external cell’s parameters (such as LAC, CI and BCCH) must be corrected.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 43
EtisalatMisr TK Project RNP Team Training
Common Problems —Call Drop TCH call drop
During the GSM network operation, call drop is the main reason the subscribers complain. It usually refers to the call dropped after TCH channel seized or conversation connected, which can be located via traffic statistics or drive test. There are many call drop causes. Such as poor signal strength, interference and improper parameters. There are two important counters related call drop, radio link timeout (RLT downlink) and SACCH multi-frame number (uplink) sent in system information. These two counters should be set properly according to the traffic and coverage.
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 44
EtisalatMisr TK Project RNP Team Training
Common Problems —Dual-band Network Optimization for dual-band network Take the following special approaches when optimize the dual-band network, most of the approaches are same as single-band network optimization: When GSM 900M and GSM 1800M network belong to a same LAC the features of two network are basically same. Parameters such as CRO can be set flexibly according to the traffic, thus can balance the traffic and avoid cell congestion. When GSM 900M and GSM 1800M network has there own location area code, CRH and CRO should be set properly to avoid frequent location update. Adjust layer thresholds to balance traffic between GSM 900 and GSM 1800 HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 45
EtisalatMisr TK Project RNP Team Training
Common Problems —Dual-band Network • Dual band network optimization elements
Cell select
Direct retry
Idle mode
Calling mode
Dedicate mode
Cell reselect
HUAWEI TECHNOLOGIES Co., Ltd.
Hand over
HUAWEI Confidential
Page 46
EtisalatMisr TK Project RNP Team Training
Exercise Questions
Please write down KPI for normal network Please write down the work flow for radio network optimization How to do for traffic balance
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 47
EtisalatMisr TK Project RNP Team Training
HUAWEI TECHNOLOGIES Co., Ltd.
HUAWEI Confidential
Page 48
View more...
Comments
