ALARM: An adaptive load-aware routing metric for hybrid wireless mesh networks

Hybrid Wireless Mesh Networks (WMN) can be quickly deployed at disasters sites to provide high-capacity wireless communications. As with other WMN networks, a routing protocol is required to find a path between non-neighboring source and destination nodes. The routing metric used by the routing protocol can have a significant impact on the performance of the network. Most of the existing routing metrics for multiradio, multihop WMNs are calculated using external information (such as link quality statistics and channel information). In a network with highly mobile nodes, such as an Hybrid WMN, the required frequent exchange of this information can be very expensive, resulting in degraded performance. In this paper, we present the ALARM routing metric, which is computed using the number of packets queued per wireless interface. This computed value offers an accurate representation of the traffic load, link quality, interference and noise levels. As only this one value need be exchanged to compute ALARM, the overhead associated with the metric is less than existing approaches. With the help of extensive simulations, we show that ALARM outperforms well-know routing metrics like ETT and WCETT under varying mobility and traffic load conditions in HybridWMNs. Validation of these simulation results is obtained from a small-scale testbed deployment.