Analysis of multi-level threshold handoff algorithm

A PCS system which consists of microcells is considered, and it is assumed that the high mobility calls and low mobility calls coexist. To enhance the quality of service the multi-level threshold handoff algorithm is used. The velocity adaptive handoff (VAH) algorithm is analyzed as one of the multi-level threshold handoff algorithm. In the VAH algorithm, the handoff threshold value is assigned according to the velocity of the mobile in order to lower the handoff failure probability and to maintain the carried traffic constantly in the handoff area. Since it is necessary to estimate the velocity of the mobile for the VAH algorithm, a velocity estimation method that use a velocity codebook is analyzed. A prioritized handoff procedure is used to evaluate the VAH algorithm in respect of the traffic characteristics.