An Integrated Planning Approach for Cellular Radio Networks

Two major planning problems must be solved in the design phase of a cellular radio network. The initial question is where to locate the base transmitter stations such that full coverage is achieved at low interference. This is relevant for frequency division (FDMA) as well as code division multiple access (CDMA) technology. To tackle this problem, precise knowledge of the radio wave propagation from each candidate base station location is necessary, particularly in urban areas. A corresponding software tool has been developed in the present project. Its main advantages are high precision and fast computation times, which is achieved by a sophisticated preprocessing phase. Once the base station positions are fixed, for FDMA systems frequencies have to be assigned such that in each cell there is a sufficient number of channels available at a low overall interference in the network. Since cell site selection and frequency allocation have mutual influence on each other, the ultimate goal is to deal with both problems in a single design step. In this paper, the above planning issues are modelled as linear integer programs and approximate solution methods for the corresponding NP-hard problems are discussed. It turns out that optimal solutions can be found for realistic problem sizes, which makes the developed software a versatile tool for third generation radio network planning.