Optimal Construction of Soft-combine Zone in a Multicast CDMA Network

Focusing on multicast transmission in a CDMA based 3G system, we address a soft-combine zone configuration problem. The problem is to find a limited number of cells supporting soft-combine such that each cell has at least one neighboring cell, which also supports soft-combine, while the sum of traffic demands of the selected cells is maximized. We show that this problem is NP-hard, introduce an integer programming formulation, and develop an algorithm generating soft-combine zone configurations. Reflecting the dynamic traffic demands change, an efficient structure for dynamic reconfiguration of soft-combine zone is proposed.