Drive Test and Optimization

Another aspect that is important in the optimization deals with drive tests. Performing a drive testing is always the best way to localize geographically and analyze problem. While Statistics give an idea about the real behavior of their geographical location, drive testing or walk testing bring a simulation of end user perception of the network on the field from one call perspective.

Drive test is the measurement process on the mobile communication system of radio waves in the air, from the Base Transceiver System (BTS) to Mobile System (MS) or vice versa, by using a cell phone designed specifically for the measurement (TEMS, NEMO etc). Drive test aims to measure the signal quality of network BTS Performance and from the results of measurement, the received information will be initialized to repair any problems associated with the end user perception, to optimize the quality and coverage. The result of Drive test will be in log files form and need to be further processed by using spesific post processor software.

GSM standards or WCDMA Network offer the possibility of monitoring the network by computing statistics. Either in BSC or in the BTS (RNC or Node B in WCDMA Technologies), each cell reports thousands of statistics about all relevant behaviors (number of attempt failure, successes during call, handover, set up, etc.) These statistics are reported to Network Management System (NMS) as counters.

To facilitate interpretation of behavior, a set of of key performance indicators (KPI) is defined out of formulas using pure counters. Each operator chooses its own KPIs and sets, according to specific criteria, some objectives to be met in order to achieve a good end user perception of the service offered and also in order to benchmark one network with other operator. The call set up failure (CSF) and drop call rate (DCR) are the main KPIs relevant failure to operator losses. People who can not access the network can not call and then do not generate traffic and people who are dropped during a call are prevented from speaking more and generating more profit.

These two rates can be computed according to various formula according to what operator wants to represents. In order to interpret properly and improve DCR and CSF values, other statistics should be monitored such as traffic, timing advance, TRX Quality, SDCCH Drop, handover distribution, handover failures, etc.

• Daily Performance data monitoring and problem troubleshooting.
• Analyze drive test measurement of sites and change parameter as necessary to optimize the quality and coverage.
• Check for any BSS alarm from sites.
• Optimize and Coverage analysis.
• Frequency re-plan.
• Identify problem due to customer complaint and change radio parameter.
• Neighbour audit.
• Drive Test KPI.