QoS routing using lower layer information in ad hoc networks

A wireless ad hoc network is an autonomous system where all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Without a network infrastructure, network nodes function as routers which discover and maintain routes to other nodes in the network. Routing in ad hoc networks has received a lot of attention due to the challenges posed by the self-organizing nature of the network, the dynamic topology, and the unreliable wireless medium. Quality of service (QoS) routing searches for routes with sufficient resources for the QoS requirements and is one of the core technologies to support QoS for real-time multimedia and data applications in ad hoc networks. We show that MAC layer information can be utilized at the routing layer via certain routing metrics for optimal route selection. We propose to use MAC delay as an indication of the level of interference of a link. Link reliability and residual bandwidth are two other routing constraints. Then, the resulting NP-complete multiple constraint routing problem is solved using a heuristic algorithm. The performance of the algorithm is studied using simulations.