ANALYSIS OF HANDOFF ALGORITHMS USING BOTH ABSOLUTE AND RELATIVE MEASUREMENTS

An analytic model has been previously developed for evaluating the per formance of handoff algorithms based on relative signal strength measu rements, i.e., the difference of signal strength from two base station s (BS's). In this paper we have extended this analysis by including an additional criterion based on absolute signal strength in the handoff decision algorithm. The absolute signal strength is the averaged valu e of the received signal level from current serving BS measured by the mobile unit, This value has to be below a fixed threshold to initiate a handoff (a necessary, not sufficient condition), In this way, the m obile unit should be assigned to a new BS if the absolute signal stren gth from the old BS drops below the threshold and the relative signal strength between the new and old BS reaches the hysteresis level, The model is proved to be sufficiently accurate by comparison with simulat ion. The effect of adding absolute signal strength is illustrated.