Optimal Path Selection Analysis in Ad Hoc Networks

This paper aims to describe a novel QoS routing protocol for ad hoc networks based on the QOLSR protocol. The proposed QoS routing protocol is based on the standardized OLSR. The OLSR protocol is an optimization of the classical link state algorithm tailored to the requirements of a mobile wireless LAN networks. The standard OLSR introduces an interesting concept, the multipoint relays (MPRs), to mitigate message overhead during the flooding process. The heuristic for the selection of MPRs limits their overall number in the network and ensures minimum overhead. However, there is no guarantee that OLSR finds the optimal path in terms of QoS requirements. We propose two heuristics for the selection of MPRs based on QoS measurements that allow QOLSR to find optimal widest paths on the known partial network topology. We demonstrate that these paths are also optimal widest paths in the whole network topology. Afterwards, we introduce the QOLSR routing table calculation based on multiple metrics. The idea is to introduce more appropriate metrics like bandwidth and delay. The implications of routing metrics on path computation are examined. We first consider algorithms for the singlemetric approach, and then we present two distributed algorithms for multiple metrics. The performance evaluation of our protocol is extensively investigated. Mathematical analysis and simulation results show that the QOLSR protocol yields better performance compared to the best-effort OLSR protocol using our proposed heuristics.