On the Minimization of Handover Decision Instability in Wireless Local Area Networks
Résumé
This paper addresses handover decision instability which impacts negatively on both user perception and
network performances. To this aim, a new technique called The HandOver Decision STAbility Technique
(HODSTAT) is proposed for horizontal handover in Wireless Local Area Networks (WLAN) based on
IEEE 802.11standard. HODSTAT is based on a hysteresis margin analysis that, combined with a utility-
based function, evaluates the need for the handover and determines if the handover is needed or avoided.
Indeed, if a Mobile Terminal (MT) only transiently hands over to a better network, the gain from using
this new network may be diminished by the handover overhead and short usage duration. The approach
that we adopt throughout this article aims at reducing the minimum handover occurrence that leads to
the interruption of network connectivity (this is due to the nature of handover in WLAN which is a break
before make which causes additional delay and packet loss). To this end, MT rather performs a handover
only if the connectivity of the current network is threatened or if the performance of a neighboring
network is really better comparing the current one with a hysteresis margin. This hysteresis should make
a tradeoff between handover occurrence and the necessity to change the current network of attachment.
Our extensive simulation results show that our proposed algorithm outperforms other decision stability
approaches for handover decision algorithm.