Application of graph theoretical methods to GSM radio network planning

The author presents some graph theoretical planning techniques which have been employed in the design of the German D1 network, a GSM (Groupe Speciale Mobile) PLMN (public land mobile network) operated by the Deutsche Bundespost Telekom. Apart from a new variant of the by now classical application of graph coloring to frequency assignment, these techniques deal with the determination of the base station identity code (BSIC), hopping sequence number (HSN), and location area code (LAC). It is shown that GSM radio network planning involves a number of optimization problems which can be treated by graph theoretical methods. The most important of these methods is concerned with the application of the principle of fractional re-use in the solution of the frequency assignment problem. The present research represents a first step towards this challenging goal