GSM Radio Network Optimization

Absolute Radio Frequency Channel Number (ARFCN)  GSM 900 F U (n) = n MHz F D (n) = Fu(n) + 45 MHz Where: 1  n  124  DCS 1800 Fu(n) = (n-512) MHz F D (n) = Fu(n) + 95 MHz Where: 512  n  885

Network Optimization Procedure Network data collection Optimization report Make optimization plan Analyze traffic data Collect DT data Integrated analysis Evaluate OMC&DT

Network Optimization Tools

Engineering Mobile Set (Test MS)

Drive Test Software

Signaling Analyzer  Software tools like MA-10 and K1205 are used for analyzing GSM signaling  It helps to analyze Abis interface, A interface and SS#7 interface signaling  These software tools are helpful in locating problems like call drop and handover failure

Network Performance Evaluation  Drive Test (DT)  Call Quality Test (CQT)

Drive Test (DT)  Evaluates connectivity, coverage, call drop and voice quality in roads  Connection ratio = (connection time / attempted time) * 100%  Call drop ratio = (call drop time / total connected) * 100%  Coverage rate = (≥ -94dBm test road in km / total test road in km) * 100%

Drive Test (DT)  Voice quality = RxQual(0-4) / RxQual (total samples) * 100 %  Carrier to Interference ratio (C/I) ≥ 12 dB

Call Quality Test (CQT)  It is used to experience network quality from the perspective of user  Sample calls are made in different locations and forms are filled out of the resulting outcome

Key Performance Indicators (KPI)  DT and CQT gives data of test routes only they do not give evaluation of overall network  For overall evaluation, KPI must be analyzed from OMC

Key Performance Indicators (KPI)  SDCCH congestion rate (< 1%)  TCH call drop rate (< 2%)  TCH congestion rate (< 2%)  Handover success rate (> 90%)  % of good RQ (0-4) (> 90%)  TCH occupancy time of TRX (> 10 s)  TCH Traffic Intensity

Repeaters  To cover shadow areas  Extends coverage of base station  Types of Repeaters Wireless Repeater Optical Repeater

Wireless Repeater  Receive signals from base station with donor antenna  Amplifies the signal  Retransmit the signal in shadow area using service antenna

Optical Repeater  At base station side signal are fed to master (local) optical repeater using coupler  Signals are transmitted via optical path  Signals are retransmitted at slave (remote) optical repeater using service antenna

Applications of Repeater  Shadow areas

Applications of Repeater  Indoor coverage

Applications of Repeater  High rise building

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