QoS-aware routing for heterogeneous layered unicast transmissions in wireless mesh networks with cooperative network coding

A novel quality-of-service (QoS)-aware routing scheme is proposed to support heterogeneous layered unicast transmissions and improve the wireless channel utilization through cooperative network coding (CNC) in lossy wireless mesh networks. The proposed routing scheme consists of two steps. In the first step, the scheme uses an optimization formulation to compute the optimal routes of all layered unicast flows. The constraints of this optimization problem, such as the transmission rate of each data layer and tolerable error rates in wireless transmissions, are derived for QoS guarantee. In the second step, the scheme decides whether or not CNC will be applied to different unicast flows at intermediate nodes. The decision criteria are determined by the network structure and the QoS guarantee. Specifically, if CNC at any intermediate node does not violate the QoS constraints of involved unicast flows, it will be applied. Otherwise, different unicast flows will be separately transmitted to their destinations without CNC. Numerical results with different network topologies and QoS requirements are conducted to demonstrate that the proposed QoS-aware routing scheme offers better throughput and channel utilization than separate unicast transmissions without CNC.