An enhanced hand-off policy to reduce blocking probability in two-layer wireless systems

Abstract

In this paper, we consider a two-layer hierarchy, i.e. micro and umbrella layer, cellular system, and propose a new hand-off mechanism to minimize call blocking probability of high-speed hand-off calls with reasonable performance of new and low-speed hand-off calls. We used double control for high-speed hand-off calls in micro and umbrella layer. By formulating Markov chains and using queueing analysis, we have derived call blocking probabilities for ours and those of other hand-off schemes. We have shown that our proposed policy can indeed improve blocking probabilities of high-speed hand-off calls, which leads to improved system performance. Our policy can serve as a guideline to design hand-off policies within wireless systems or inter-working policies between systems. © Springer-Verlag Berlin Heidelberg 2003.