Cell Planning in WCDMA Networks for Service Specific Coverage and Load Balancing

Third-generation (3G) Wideband Code Division Multiple Access network is an evolutionary network which supports services from circuit-based voice service to high and low rate packet-based data services. Unlike the voice oriented second-generation service, the 3G network is enhanced to support services with different data rate, different asymmetry, and different coverage. We thus need to investigate the coverage of multiple services and the capacity of a cell in cell planning for the advanced network. Service specific uplink coverage and downlink capacity with load balancing are considered in our cell planning. The problem is formulated as a linear integer programming optimization model. An efficient tabu search heuristic is developed to solve the NP-hard problem. Very promising computational results are demonstrated, where the solution gap from the optimal to the lower bound by CPLEX is within 0.9% in problems to cover all service traffic in the system. It is demonstrated that higher load factor effectively reduces cell sites for multiple service classes. Load balancing among cells is also demonstrated with different coverage ratio.