Handoff management with a delay requirement in femtocell networks

Abstract

Radio communication has come a long way from the initially deployed 1G voice (Amps) to modern 3G and 4G networks. A technology that holds promise to provide the next leap in peformance is femtocell. Femtocell technology brings the network closer to the user by adding smaller cells, which provide the benefit of higher quality links and more spatial reuse. To fully exploit this diversity realized at the physical layer some challenging issues have to be addressed. Making a handoff decision is one such issue where the user has various power levels available from Macro Base Station (MBS) and Femto Base Station (FBS). From a Base Station's (BS) perspective, there may be many users with close SINR values needing service but all users cannot be accommodated due to bandwidth limitation. To make these decisions, appropriate handoff mechanisms need to be adapted to fully exploit the advantages of these networks in various scenarios. In this paper, we extensively study methods to optimize handoff decisions under the open access scheme of operation, maintaining Quality of Service (QoS) thresholds to maximize overall network capacity such that fairness among users is maintained as well. We aim at developing a low-complexity algorithm with a small dwell time before handing off a macrocell user to a nearby femtocell and vice-versa. When the number of users in the network is smaller in comparison to the available FBSs, we observe better performance in reducing unnecessary handoffs.