Optimizing UMTS radio coverage via base station configuration

Due to the W-CDMA radio interface, the area covered by a set of UMTS base stations depends on the signal quality requirements, the power control mechanism as well as on the traffic distribution. In previous work we have proposed discrete optimization models and algorithms for locating base stations in UMTS networks. In this paper we address the general problem of optimizing base station locations as well as their configurations, such as antenna height, tilt, and sector orientation. The proposed model, which can also be used to only optimize the base station configurations, accounts for the power control mechanism typical of W-CDMA and considers the signal-to-interference ratio (SIR) as quality measure. To find good approximate solutions of this NP-hard problem, we develop a Tabu Search algorithm which takes into account traffic coverage and installation costs. Experimental results showing the effect of considering base station configurations in the planning process are reported.