Call Admission Control in Small Cell Networks with Retrials and Guard Channels

Abstract

Recent trends in mobile cellular networks turn towards deployment of Small Cell Networks (SCNs), where the cell size gets smaller and thus the number of subscribers served in a cell will be relatively smaller and should be considered finite. However, almost works on cellular mobile networks consider an infinite population cell, resulting commonly in infinite queueing models, for which no analytical solution is available for performance measures and only numerical approximations can be obtained. In this paper, a Call Admission Control (CAC) in a finite population micro-cell operating in a SCN, with retrials of blocked new calls, impatience of subscribers and multiple guard channels dedicated to handoff calls, is proposed. For the numerical computation of the steady-state probabilities of the corresponding continuous time Markov chain (CTMC), an efficient algorithm giving automatically the infinitesimal generator is developed, and various performance measures are established in network parameters and stationary probabilities. The guard channels number and retrials effect on the network performance in terms of blocking probability (for new calls and retrials) and dropping probability (of handoffs) is also carried out via experimental results.