Performance analysis of an adaptive handoff algorithm based on distance information

Abstract

Mobility is the most important feature of a wireless cellular communication system. Handoff, the process of changing the channel associated with the current connection while a call is in progress, is a key concept in providing this mobility. Continuation of an active call is one of the most important quality measurements in the cellular systems. Handoff makes it possible for a user to travel from one cell to another while having a seamless connection. In this study, an adaptive handoff algorithm with a dynamic hysteresis value, based on the distance between the mobile station and the serving base station, is proposed for cellular communications. Handoff probability is calculated to evaluate handoff algorithms analytically. The proposed handoff algorithm is compared with an algorithm with a fixed hysteresis value, algorithm based on absolute and relative signal strength measurements and algorithm based on distance and relative signal strength measurements. Performance is evaluated in terms of the average number of handoffs, average handoff delay, standard deviation of handoff location, average signal strength during handoff, and probability of link degradation. Numerical results and simulations demonstrate that the proposed algorithm outperforms the handoff algorithm with fixed hysteresis level, handoff algorithm using both threshold and hysteresis, and handoff algorithm based on distance and hysteresis. The effect of distance error is also discussed.