Dynamic sectorization of microcells for balanced traffic in CDMA: genetic algorithms approach

With the increase of cellular users the traffic hot spots and unbalanced call distributions are common in wireless networks. As a solution to this problem, the CDMA techniques enable a base tranciever station to connect microcells with optical fibers and to control the channels by sectorizing the microcells. To solve the load balancing among microcells we dynamically sectorize the microcells depending on the time-varying traffic. The microcell sectorization problem is formulated as an integer linear programming which minimizes the blocked and handoff calls in the network. In the proposed sectorization proper, connected, and compact sectors are considered to keep the handoffs as small as possible, while satisfying the channel capacity at each sector. Three genetic algorithms (GAs) are proposed to solve the problem: standard GA, grouping GA and parallel GA. Computational results show that the proposed GAs are highly effective. All three GAs illustrate outstanding performance for small size problems. The parallel GA which is based on the operators used in grouping GA demonstrates excellent solution quality in a reasonable time. ∗ This work was supported by grant No. 1999-2-315-001-3 from the Basic Research Program of the Korea Science & Engineering Foundation ∗∗ Contela Inc., 9-1 Sunae dong, Bundang gu, Sungnam si, Kyunggi do, 463-783, Korea