Energy Savings in OFDM Systems through Cooperative Relaying

ETRI Journal

关键词: forward error correction codes;    OFDM;    selection relaying;    Cooperative relaying;   

Others  :  1185595
DOI  :  10.4218/etrij.07.0106.0085

【 摘 要 】

Energy savings in orthogonal frequency division multiplexing (OFDM) systems is an active research area. In order to achieve a solution, we propose a new cooperative relaying scheme operated on a per subcarrier basis. This scheme improves the bit error rate (BER) performance of the conventional signal-to-noise ratio (SNR)-based selection relaying scheme by substituting SNR with symbol error probability (SEP) to evaluate the received signal quality at the relay more reliably. Since the cooperative relaying provides spatial diversity gain for each subcarrier, thus statistically enhancing the reliability of subcarriers at the destination, the total number of lost subcarriers due to deep fading is reduced. In other words, cooperative relaying can alleviate error symbols in a codeword so that the error correction capability of forward error correction codes can be fully exploited to improve the BER performance (or save transmission energy at a target BER). Monte-Carlo simulations validate the proposed approach.

   

【 参考文献 】

• [1]D.N.C. Tse and P. Viswanath, Fundamentals of Wireless Communication, Cambridge University Press, 2005.
• [2]G.J. Foschini and M.J. Gans, "On Limits of Wireless Communications in Fading Environment When Using Multiple Antennas," Wireless Personal Commun., vol. 6, Mar. 1998, pp. 311-335.
• [3]L. Zheng and D.N.C. Tse, "Diversity and Multiplexing: A Fundamental Tradeoff in Multiple Antenna Channels," IEEE Trans. Inform. Theory, vol. 49, no. 5, May 2003, pp. 1073-1096.
• [4]E. Telatar, "Capacity of Multi-Antenna Gaussian Channels," European Trans. Telecommun., vol. 6, Nov. 1999, pp. 585-595.
• [5]A. Nosratinia, T.E. Hunter, and A. Hedayat, "Cooperative Communication in Wireless Networks," IEEE Commun. Mag., vol. 42, no. 10, Oct. 2004, pp. 74-80.
• [6]S. Basagni, M. Conti, S. Giordano, and I. Stojmenovic, Mobile ad hoc Networks, John Wiley & Sons, 2004.
• [7]G.L. Stuber, Principles of Mobile Communications, Kluwer Academic Publishers, 2001.
• [8]M. Dohler, E. Lefranc, and H. Aghvami, "Virtual Antenna Arrays for Future Mobile Communication Systems," IEEE ICT2002, China, June 2002.
• [9]M. Dohler, J. Dominguez, and H. Aghvami, "Link Capacity of Virtual Antenna Arrays," IEEE VTC2002-Fall, vol. 1, Sep. 2002, pp. 440-443.
• [10]R. Pabst, B. Walke, D. Schultz, P. Herhold, H. Yanikomeroglu, S. Mukherjee, H. Visvanathan, M. Lott, W. Zirwas, M. Dohler, H. Aghvami, D. Falconer, and G. Fettweis, "Relay-Based Deployment Concepts for Wireless and Mobile Broadband Cellular Radio," IEEE
• [11]H. Hu, H. Yanikomeroglu, D. Falconer, and S. Periyalwar, "Range Extension without Capacity Penalty in Cellular Networks with Digital Fixed Relays," IEEE Globecom, vol. 5,?Nov.-Dec. 2004, pp. 3053-3057.
• [12]R.V. Nee and R. Prasad, OFDM for Wireless Multimedia Communications, Artech House, 2000.
• [13]J.N. Laneman, D.N.C. Tse, and G.W. Wornell, "Cooperative Diversity in Wireless Networks: Efficient Protocols and Outage Behavior," IEEE Trans. Inform. Theory, vol. 50,?no. 12,?Dec. 2004, pp. 3062-3080.
• [14]T.E. Hunter and A. Nosratinia, "Cooperation Diversity through Coding," IEEE ISIT2002, Switzerland, June 30 - July 5, 2002, pp. 22.
• [15]Y.G. Kim and S.W. Kim, "Optimum Selection Combining for M-ary Signals in Frequency-Nonselective Fading Channels," IEEE Trans. Commun., vol. 53,?no. 1,?Jan. 2005, pp. 84-93.
• [16]A. Stefanov and E. Erkip, "Cooperative Coding for Wireless Networks," IEEE Trans. Commun., vol. 52,?no. 9,?Sep. 2004, pp. 1470-1476.
• [17]Y. Hua, Y. Mei, and Y. Chang, "Wireless Antennas - Making Wireless Communications Perform Like Wireline Communications," IEEE Topical Conf. on Wireless Commun. Technology, Oct. 2003, pp. 47-73.
• [18]H. Ochiai, P. Mitran, and V. Tarokh, "Design and Analysis of Collaborative Diversity Protocols for Wireless Sensor Networks," IEEE VTC2004-Fall, vol. 7, Sep. 2004, pp. 4645-4649.
• [19]M.K. Simon and M.S. Alouini, Digital Communication over Fading Channels, Second Edition, John Wiley & Sons, 2005.
• [20]D.G. Brennan, "Linear Diversity Combining Techniques," Proc. of the IEE, vol. 91,?no. 2, Feb. 2003,?pp. 331-356.
• [21]N. Ahmed, M.A. Khojastepour, and B. Aazhang, "Outage Minimization and Optimal Power Control for the Fading Relay Channel," IEEE Information Theory Workshop, Oct. 2004, pp. 458-462.