QoS-aware routing protocol for heterogeneous wireless unicasts with cooperative network coding

This paper proposes a QoS-aware routing protocol in lossy wireless networks to support heterogeneous layered unicast transmissions and to improve energy usage through cooperative network coding (CNC). The proposed protocol consists of two steps. The first step uses an optimization framework to compute routes of all layered unicast flows. The constraints of this optimization problem are based on the Quality-of-Service (QoS) guarantee, the transmission rate of each data layer, and interference effects in wireless transmissions. The second step decides whether or not CNC will be applied to different unicast flows at intermediate nodes. The decision criterions are based on the network structure and the QoS guarantee. In particular, if CNC at any intermediate node does not result in violating the QoS requirements of the involved unicast flows, CNC will be applied. Else, different unicast flows will be separately transmitted to destinations without CNC. Numerical results from different network topologies and QoS requirements show that the proposed routing protocol gives better throughput and energy efficiency while providing the QoS guarantees to multiple unicast flows compared to existing unicast transmission schemes.