Adaptive Semi-soft Handoff for Cellular IP Networks

Abstract

Various advances in technologies have led to a myriad of wireless mobile devices to ubiquitously connect to the internet. This creates a significant demand for seamless wireless network connectivity. The Cellular IP semi-soft handoff protocol has been proposed to satisfy this demand. Studies have shown that it performs better than the conventional hard handoff protocol. However, these studies are based on unrealistic assumptions of symmetrical network topologies and fixed loads. In practice, network topology can be asymmetric and network load fluctuates. Semi-soft handoff uses fixed handoff parameters for stream synchronization and mobile hosts tune-in time, which may work well for the symmetrical network setups, but performs poorly with unbalanced and dynamically changing networks. This paper proposes adaptive semi-soft handoff protocol (Adaptive-SS) to address this issue by dynamically changing handoff parameters based on network conditions during handoff. Our simulation study shows that Adaptive-SS significantly reduces network traffic and packet losses/duplications during handoff, while still minimising handoff latency.