Delay Optimization and Cross-Layer Design in Wireless Multi-Hop Networks with Network Coding and Successive Interference Cancellation

Network coding (NC) and multi-packet reception (MPR) with successive interference cancellation (SIC) have been shown to improve the performance of multi-hop 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 multi-path 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. 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.