Mining of Reuse Patterns in CDMA Network Optimization

CAP, a classical problem in cellular mobile communication networks such as GSM/GPRS or CDMA cellular mobile networks, refers to assigning a limited number of available channels to many mobile voice or data users while minimizing electromagnetic interferences. Most existing researches on CAP focus mainly on channel separation constraints, but pay little attention to geometric constraints defined by reuse patterns that is of great value in engineering applications. An extended CAP model named RCAP (reuse-pattern-oriented CAP) is proposed, which takes account of both of these two constraints. A systematic solution to RCAP is elaborated, which includes two sequential steps, i.e., partition of reuse groups and channel assignment in the groups. Partition of reuse groups is reduced to subgraph isomorphism and can be tackled by subgraph mining while channel assignment in groups is solved in a heuristic manner. The effectiveness of RCAP and its solution was verified by three benchmarks. RCAP was applied to PN offsets assignment in the CDMA networks in several cities of Liaoning Province, and a case study is illustrated in the paper. These results indicate that the proposed RCAP scheme is a very promising solution to channel assignment problems in practical CDMA networks.