A MODEL FOR ANALYZING HANDOFF ALGORITHMS

We present a model for analyzing the performance of handoff algorithms based on signal strength measurements made by mobile stations in a lo gnormal fading environment. This model enables us to evaluate the effe ct of averaging and hysteresis on the handoff process. Handoffs are re lated to level crossings of the difference between the received signal strengths from two base stations. The algorithm performance is derive d by modeling the level crossings as Poisson processes with time-varyi ng rate functions. The model is seen to yield results that agree with simulations over the range of algorithm parameters of practical intere st. These results can be used to determine the averaging interval and hysteresis level that achieve the optimum tradeoff between the number of unnecessary handoffs and the delay in handing off.