NCOM: Network Coding Based Overlay Multicast in Wireless Networks
The capacity of wireless networks are increasingly challenged by the traffic stresses generated by data-intensive applications. Multicast is a bandwidth-efficient solution to simultaneously disseminate data to multiple receivers. In this paper, the authors present NCOM, a network coding based overlay multicast design that integrates Network Coding (NC), Opportunistic Routing (OR), and cross-layer link scheduling to achieve high efficiency and reliability multi-hop wireless multicast. In NCOM, the source and receivers are connected by an overlay Steiner tree optimized for the minimum OR distance between nodes. With NC, coded packets are opportunistically transmitted along overlay links. The transmissions of adjacent nodes in the overlay multicast are coordinated by a novel multicast acknowledgement and cross-layer MAC scheduling.