Time and power scheduling in an ad hoc network with bidirectional relaying and network coding

Network coding (NC) is a technique that allows intermediate nodes to combine the received packets from multiple links and forwarded to subsequent nodes. Compared with pure relaying, using NC in a wireless network, one can potentially improve the network throughput, but it increases the complexity of resource allocations as the quality of one transmission is often affected by the transmission conditions of multiple links. In this paper, we consider an ad hoc network, where all the links have bidirectional communications, and a relay node forwards traffic between the source and the destination nodes using NC. All transmissions share the same frequency channel, and simultaneous transmissions cause interference to each other. We consider both digital NC and analog NC strategies, referred to as DNC and ANC, respectively, and schedule transmission time and power of the nodes in order to maximize the overall network throughput. For DNC, an optimum scheduling is formulated and solved by assuming that a central controller is available to collect all the link gain information and make the scheduling decisions. Distributed scheduling schemes are proposed for networks using DNC and ANC. Our results indicate that the proposed scheduling scheme for DNC achieves higher throughput than pure relaying, and the scheduling scheme for ANC can achieve higher throughput than both DNC and pure relaying under certain conditions. Copyright © 2013 John Wiley & Sons, Ltd. This paper studies transmission power allocations and time scheduling in an ad hoc network with bidirectional communication links and using network coding. All transmissions use the same frequency channel. Both digital and analog network codings are considered. Distributed scheduling and power allocations schemes are proposed. Numerical results show that much higher throughput can be achieved using digital network coding or analog network coding and the proposed schemes, compared with optimum time scheduling and power allocations using pure relaying.