Minimizing Handoff Ping-Pong Effect in 802.11 Data Networks Using Differential RSS and Extrapolation

Handoff is a potentially disruptive process that a mobile client is likely to frequently experience. Therefore, it is desirable to minimize the number of performed handoffs. Besides reducing disruptiveness of a handoff, it is also necessary to intelligently decide when to handoff and which new access point to connect to. Mobile nodes that choose the handoff instant and handoff access point poorly may cause excessively frequent handoffs. This may result in high cost to both the clients and the infrastructure, especially if a handoff involves expensive operations, such as public key authentication. In this paper, we try to eliminate the ping-pong effect and minimize unnecessary handoffs by applying the concept of differential RSS (Received Signal Strength) and extrapolating the measured points in order to estimatethe time for a connection to be lost. We perform some simulations to proof the effectiveness of this approach and compare it to the handoff decisions based on RSS thresholds and hysteresis