Performance Improvement of the DSRC System Using a Novel S and Π-Decision Demapper

Jeich MAR, Chi-Cheng KUO

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DOI: 10.4236/wsn.2009.14033                

Abstract

Based on the constellation diagram of the different modulations, a novel S and Π-decision rule is designed for the analog demapper of the orthogonal frequency-division multiplexing (OFDM) systems. The dedicated short-range communications (DSRC) system is chosen as an OFDM platform to compare the performance among the proposed S and Π-decision decoder, hard-decision and soft-decision decoders. Simulation results demonstrate that both the complexity and performance of S and Π-decision demapper used for M-ary quad-rature amplitude modulation (QAM) OFDM system can be greatly improved. The number of decisions be-tween the received symbol and constellation points can be simplified to look up table times for M-ary QAM OFDM system.

Keywords

S and Π-decision Rule, Analog Demapper, DSRC System, OFDM

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K. M. Lee, D. S. Han, and K. B. Kim, “Performance of the Viterbi decoder for DVB-T in Rayleigh fading channels,” IEEE Trans. Consumer Electron., Vol. 44, pp. 994–1000, August 1998.
[2]	S. B. Wicker, “Error control systems for digital communication and storage,” New Jersey, Prentice-Hall, Inc., 1995.
[3]	F. Tosato and P. Bisaglia, “Simplified soft-output demapper for binary interleaved COFDM with application to HIPERLAN/2,” in Proc. IEEE Int. Conf. Communications, Vol. 2, pp. 664–668, April 2002.
[4]	E. Akay and E. Ayanoglu, “Low complexity decoding of bit-interleaved coded Modulation for M-ary QAM,” in Proc. IEEE Int. Conf. Communications, Vol. 2, pp. 901– 905, June 2004.
[5]	K. He and G. Cauwenberghs, “Performance of analog Viterbi decoding,” 42nd Midwest Symposium on Circuits and Systems, Vol. 1, August 1999.
[6]	K. He and G. Cauwenberghs, “Itergrated 64-state parallel ana-log Viterbi decoder,” ISCAS 2000, Vol. 4, May 2000.
[7]	Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle System–5Ghz Band Dedicated Short Range Communications (DSRC) Medium Ac-cess Control (Mac) and Physical Layer (PHY) Specifications, IEEE802.11p, December 2005.
[8]	S. Coleri, M. Ergen, and A. Bahai, “Channel estimation tech-niques based on pilot arrangement in OFDM systems,” IEEE Trans. Broadcast., Vol. 48, pp. 223–229, September 2002.
[9]	J. Giarratano and G. Riley, Expert Systems, 2nd. Edition, PWS Publishing Company, 1994.
[10]	J. Heiskala and J. Terry, OFDM Wireless LANs: A Theoretical and Practical Guide, Sams, 2001.
[11]	V. C. Gaudet, R. J. Gaudet, and P. G Gulak, “Programmable in-terleaver design for analog iterative decoders,” IEEE Trans. Cir-cuits Syst. II, Vol. 49, pp. 457–464, July 2002.
[12]	D. G. Manolakis, V. K. Ingle, and S. M. Kogon, “Statistical and adaptive signal processing,” McGraw-Hill, Education, 2000.
[13]	Y. Zhao and A. Huang, “A novel channel estimation method for OFDM mobile communication systems based on pilot sig-nals and transform-domain processing,” in Proc. IEEE VTC, Vol. 3, pp. 2089–2093, May 1997.
[14]	J. Rinnie and M. Renfors, “Pilot spacing in orthogonal fre-quency division multiplexing systems on practical channels,” IEEE Trans. Consumer Electron., Vol. 42, No. 4, pp. 959–962, November 1996.
[15]	IEEE 802.11a, IEEE standard for Wireless LAN Medium Ac-cess Control (MAC) and Physical Layer (PHY) specifications, 1999.
[16]	M. R. G. Butler and A. R. Nix, “Quantization loss for convolu-tional decoding in Rayleigh-fading channels,” IEEE Commun. Lett., Vol. 7, No. 9, pp. 446–448, September 2003.
[17]	W. C. Jakes, Microwave Mobile Communications, New York: IEEE Press, 1974.