On threshold setting and hysteresis issues of handoff algorithms

Handoff is the mechanism that transfers an ongoing call from one cell to another as a user moves through the coverage area of a cellular system. Studies on the performance of handoff algorithms using both absolute signal strength and relative signal strength measurements are carried out. A scheme is considered in which handoff initiation is based on the absolute signal strength of an approaching base station along with the relative signal strength of the base stations. As a performance measure we use expected average signal strength (EASS) of the base station at which handoff occurs. The effect of using absolute signal strength of an approaching base station instead of the serving base station signal strength after the selection of probable base station to which call has to be handed over is illustrated. Results of a simulation study are included to substantiate our views