Delay Optimization and Cross-Layer Design in Multihop Wireless Networks With Network Coding and Successive Interference Cancelation

Network coding (NC) and multipacket reception with successive interference cancellation (SIC) have been shown to improve the performance of multihop wireless networks (MWNs). However, previous work emphasized maximization of network throughput without considering quality of service (QoS) requirements, which may lead to high packet delays in the network. The objective of this work is minimization of packet delay in a TDMA-based MWN that is jointly utilizing NC and SIC techniques for a given traffic demand matrix. We assume conflict-free scheduling and allow multipath routing. We formulate a cross-layer optimization that assigns time slots to links in a way that the average packet delay is minimized. The problem formulation results in a difficult mixed integer nonlinear programming (MINLP) that the state-of-art software can only solve for very small-sized networks. For large networks, we develop a heuristic approach that iteratively determines the optimal solution. We present numerical results, which show that the average packet delay and traffic handling capacity of a network, using w/o NC+SIC, NC, SIC and NC+SIC schemes, improves from left to right. The traffic capacity of NC+SIC is double of the w/o NC+SIC. Thus, combined utilization of NC and SIC techniques results in significant performance improvement.