Optimizing frequency planning in the GSM system

Frequency planning is an important process in planning and optimising second generation TDMA mobile networks. For the GSM system, frequency planning is usually performed by controlling only the downlink estimated quality in the territory. In this paper, by means of simulation results, field measurements and theoretical analysis, we verify that the uplink and downlink in the GSM system experience a different quality, and the uplink may locally exhibit the worst performance, particularly in high traffic load conditions. Thus we propose an alternative approach to take into account both links in the frequency planning process of the GSM system which could be particularly suitable for the local optimisation of an existing frequency plan, in order to improve the quality of critical cells.