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A Full Journal Paper, authored by Mr. Pen Shun Lu, Information Theory and Signal Processing Laboratory, School of Information Science, has been published in IEEE Transactions on Vehicular Technology

[Title of the paper]
Joint Adaptive Network-Channel Coding for Energy-Efficient Multiple Access Relaying
Pen-Shun Lu
Xiaobo Zhou, Prof. Khoirul Anwar and Prof. Tad Matsumoto
[Acceptance Notification Date]
November 25th, 2013
An energy-efficient orthogonal multiple access relay channel (MARC) system is proposed in this paper where accumulator and differential detection (DD) are used at the source and relay nodes. However, the weak decoding capability of DD degrades the performance of the MARC system if the conventional decoded-and-forward relaying strategy is applied. In this paper, a novel joint adaptive network-channel coding (JANCC) technique is proposed to support DD by making efficient use of the erroneous estimates output from DD. In the JANCC technique, the destination constructs a vector identifying the indexes of the source nodes whose information parts contain errors, and sends it to the relay to request a retransmission. The relay performs network coding by taking the exclusive-OR (XOR)-operation only over the stored estimates specified by the identifier vector, which aims to avoid unnecessary erroneous estimates being coded. The decoding algorithm of JANCC first performs each user's iterative (turbo) decoding process, and the a posteriori Log-Likelihood Ratio (LLR) obtained after the each user's decoding process is used as a priori LLR for the decoding of the other users' decoding chain.

The utilization of DD significantly reduces the computational complexity, which leads to meaningful power saving with only a small loss in the FER performance by the proposed JANCC decoding algorithm.


It should be noted here that this research has been conducted under the financial/technical support of JAIST-University of Oulu Dual Degree Program. We, the author and the co-authors, would like to thank the support provided by the university. We shall continue making our research efforts and exhibiting high research activities so that we can always lead the academic society of Information Theory and Signal Processing for Wireless Communications.

[About the Journal]
The rank of IEEE Transactions on Vehicular Technology is at the 4th position in among 68 journals related to communications, according to Eigen Factor. Please see more details at:

The author's version of the paper is available at:
(from left) Mr. Xiaobo Zhou, Mr. Pen-Shun Lu, and Prof. Tad Matsumoto

December 13, 2013