Rate and Power Adaptation for Analog Network Coding

Network coding is an emerging technique of packet forwarding that encodes the packets at the relay node to increase the throughput of a relaying network. Analog network coding (ANC) encodes the packets by superposing the signals at the physical layer, which can further bring throughput improvements. In this paper, we first analyze the coding procedure of ANC and elaborate the fact that the maximum possible number of coding nodes in ANC is two for common wireless transceivers. Then, we propose a rate adaptation scheme for ANC. We show that the transmission powers of nodes affect the data rate and that transmitting at the maximum power is not always optimal. Based on this observation, we propose a method of finding the optimal transmission power that maximizes the data rate. We also discuss some issues that need to be considered when implementing the proposed scheme in practical wireless systems. Then, the performance of the proposed scheme is evaluated through extensive simulations. The simulation results show that the proposed joint rate and power adaptation scheme outperforms ANC without power adaptation and that it is beneficial over other relaying schemes in a broad range of scenarios of mobile and vehicular applications.