Analysis Of Cell Coverage In GSM Networks

GSM networks consist of a series of cells; cell coverage refers to the areas and scopes covered by the downlink radio from the base stations attached to the cells. Whether the coverage of the cell is appropriate and matches to the cell's capacity are important to the quality of services in networks. As the mobile users make higher requirements on the quality of services in networks, cell coverage becomes an aspect that cannot be ignored, and adjusting and optimizing of cell coverage is crucial to GSM network optimization.There are many factors relating to the coverage of cells, where the antenna azimuth is an important one affecting the areas of cell coverage in networks; Inappropriate azimuths may lead to excessive or weak coverage and have severe impact on the quality of services in networks, so it is necessary to verify the azimuths of antenna and analyze whether or not there exist excessive or weak coverage in networks.An efficient method of azimuth verification is presented, which makes use of the data of network configuration and interference measurement, by means of the vector-weighted scheme, to evaluate the deviations between the cells'configuration azimuths and their actual azimuths, and make further judgments on whether or not the antennas are correctly installed, in line with the configuration data, in real networks; the data of interference measurement reflects the distribution of signal to interference ratio in the overlap areas the coverage of serving sectors and interfering sectors.An approach to analysis of excessive coverage based on NCS measurement data is elaborated, and identification of weak coverage and excessive coverage in back direction based on the results of azimuth verification is also illustrated. By making use of C# programming language, MapXtreme 2005 and SQL Server 2005 database, the system of cell coverage analysis is implemented.Applying of azimuth verification and coverage analysis to the GSM networks in several cities in Guangdong Province gives empirical evidences that antenna azimuth deviations and inappropriate cell coverage are somewhat common in real GSM networks, and the schemes proposed successfully recognize azimuth inconsistency and find out undue coverage in networks, thus contributing to improve the quality of services in real networks. KEY WORDS:GSM network, coverage analysis, azimuth verification, excessive coverage, weak coverage...