Table of Contents
ISRN Communications and Networking
Volume 2011, Article ID 186783, 8 pages
Research Article

Energy-Efficient Relaying Strategy with Network Coding in Two-Way Parallel Channels

1Research Institute of Information Technology, Tsinghua University, Beijing 100084, China
2Communication Systems, Royal Institute of Technology (KTH), 16440 Stockholm, Sweden

Received 25 November 2010; Accepted 11 January 2011

Academic Editor: A. Maaref

Copyright © 2011 Ning Hu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We consider a two-way communication assisted by parallel regenerative decode-and-forward relays operating in orthogonal channels. In a system with limited channel state information at each source and relay node, an optimum distributed power allocation strategy is proposed to minimize the total transmit power, providing a target signal-to-noise ratio at each destination with a target outage probability. Moreover, combined with opportunistic relaying and network coding, a distributed decision mechanism is proposed for the relay node to decide whether to help the transmission or not. In this proposal, each source works out the transmit power and the decision threshold then broadcasts them. The selected relay compares the decision threshold with the channel gain of its weaker relay-to-destination link, then determines whether to forward the networkcoded data or not. Simulation results show the advantage of this strategy in terms of energy efficiency for a two-hop two-way communication scenario. The proposed strategy is very flexible as it can trade outage to power consumption and vice versa.