Performance comparisons of call admission control algorithms in cellular systems

Abstract

This paper compares six call admission control algorithms for a cellular system that carries a single class of homogeneous traffic and uses fixed channel assignment (FCA). The algorithms are as follows: the weighted sum scheme, the reservation scheme, the linear weighting scheme, the distributed admission control scheme, the probability index scheme, and the hybrid control scheme. Each algorithm attempts to optimize two quality of service (QoS) metrics: the new call blocking probability, which is the probability that a new call is denied access to the system, and the forced-termination probability, which is the probability that an admitted call is terminated prematurely. Through extensive simulation, we first compare these algorithms' ability to meet QoS requirement at a known load, and then explore the performance they can achieve when load differs from its expected level. Based on our simulation results, when the load is predictable, no known algorithm significantly outperforms the reservation scheme. When the load can vary unpredictably, the hybrid control scheme yields the best performance.