Evaluation of available bandwidth as a routing metric for delay-sensitive IEEE 802.15.4-based ad-hoc networks

In this paper, we evaluate available bandwidth as a routing metric for IEEE 802.15.4-based ad-hoc networks. The available bandwidth on a data forwarding path is an approximation of the forwarding path's residual data relaying capacity. High available bandwidth on a data forwarding path implies low data traffic load on the path, therefore data flows may experience low delay and high packet delivery ratio (PDR). Our aim is to evaluate available bandwidth as a routing metric. We present different available-bandwidth-based routing protocols for IEEE 802.15.40-based networks, namely: end-to-end available-bandwidth-based routing protocol (ABR), available bandwidth and contention-aware routing protocol (ABCR), and shortest hop-count and available-bandwidth-based opportunistic routing protocol (ABOR). Moreover, we also present variants of ABR and ABCR capable of distributing a flow's data packets on multiple paths by maintaining the top K downstream nodes (the downstream nodes that advertised best data forwarding paths towards a sink node) corresponding to each sink node in a routing table. We focus on both single-sink and multi-sink networks. We performed extensive simulations, and the simulation results demonstrate that the available bandwidth routing metric shows better results when combined with a routing metric that helps to limit a data forwarding path's length, i.e., shortest hop-count or intra-flow contention count. For multi-path data forwarding towards the same sink node, and at high traffic volumes, the available bandwidth metric demonstrates best performance when combined with the shortest hop-count routing metric. (C) 2015 Elsevier B.V. All rights reserved.