On the Effect of the Size of the Pre-reservation Area on Handoff Performance in Wireless Cellular Networks

In wireless cellular networks, a roaming mobile station (MS) is expected to move from one cell to another. It is essential to ensure that, when a MS traverses from one cell to another, an ongoing connection of that MS is not dropped. Pre-reservation schemes allow the reservation of bandwidth for an ongoing call in an adjacent cell before the MS moves into that cell, so that the call is sustained when the MS moves into this adjacent cell. Pre-reservations are made when the MS is within some distance of current cell boundary. This distance determines the area in the cell in which the MS can make pre-reservations. In this paper, we develop an analytical model to study the effects of varying the pre-reservation area on the system performance in terms of blocking probability of new calls, dropping probability of handoff calls and call incompletion probability (probability that calls are terminated prior to completion). Our studies show that as we increase the pre-reservation area, the performance improves initially. However, beyond a certain point, the performance begins to degrade due to a large number of “false” pre-reservations. Also the performance of the pre-reservation scheme is closely related to MSs’ mobility pattern.