Influence of hand-off algorithms on the performance of cellular radio networks

The influence of different hand-off algorithms on the channel demand, the interference, and the spectrum demand is analysed for a sample radio network with 35 base stations over both a regular plane area and a real topography. First, the field strength and service probability have been predicted. Then the so-called assignment probabilities have been determined by different analytical hand-off models: One based on field strength, the other based on relative distance measurement with different precision assumptions. Due to different assignment probabilities, all subsequent performance characteristics become different, e.g. the traffic channel demand of a base station (up to 120 % variance), the interference between each pair of base stations, and the spectrum demand of the whole radio network (up to 100 % variance). There is no obvious winner among the realistic hand-off algorithms. The performance of the algorithm based on distance measurement is very sensitive to its precision: As far as the spectrum demand of the network is concerned, it could be much better and much worse than the algorithm based on field strength. This applies to both the ideal and the real topography.