BASH: A backhaul-aided seamless handoff scheme for Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are comprised of mesh routers whose relatively small transmission range may result infrequent handoffs, leading to high packet delays and loss rates and limiting the performance of real-time applications over WMNs. In this work, we propose BASH - a backhaul-aided seamless handoff scheme. Our scheme takes advantage of the wireless backhaul feature of WMNs and allows a mobile station to probe the neighboring mesh routers by accessing the backhaul channel. After the probe request, the mobile station is able to switch back to its primary communication channel and resume its ongoing communication without waiting for the probe responses. The currently associated mesh router of the mobile station collects the probe responses and selects the new mesh route on behalf of the mobile station. Our works show that by utilizing the wireless backhaul, BASH (1) reduces the probing latency and, thus, the Layer-2 handoff latency; (2) allows partial overlap of the Layer-2 and Layer-3 handoffs, reducing the overall handoff latency; and (3) shortens the authentication latency by utilizing the transitivity of trust relationship. The experimental results show that BASH achieves an average Layer-2 handoff of 8.7ms, which supports the real-time applications during the handoff.