Opportunistic Error Correction: When Does It Work Best for OFDM Systems?

Xiaoying Shao, Cornelis H. Slump

Signals and Systems Group, University of Twente, Enschede, The Netherlands.

DOI: 10.4236/ijcns.2013.611048                

Abstract

The water-filling algorithm enables an energy-efficient OFDM-based transmitter by maximizing the capacity of a frequency selective fading channel. However, this optimal strategy requires the perfect channel state information at the transmitter that is not realistic in wireless applications. In this paper, we propose opportunistic error correction to maximize the data rate of OFDM systems without this limit. The key point of this approach is to reduce the dynamic range of the channel by discarding a part of the channel in deep fading. Instead of decoding all the information from all the sub-channels, we only recover the data via the strong sub-channels. Just like the water-filling principle, we increase the data rate over the stronger sub-channels by sacrificing the weaker sub-channels. In such a case, the total data rate over a frequency selective fading channel can be increased. Correspondingly, the noise floor can be increased to achieve a certain data rate compared to the traditional coding scheme. This leads to an energy-efficient receiver. However, it is not clear whether this method has advantages over the joint coding scheme in the narrow-band wireless system (e.g. the channel with a low dynamic range), which will be investigated in this paper.

Keywords

Water-Filling; Opportunistic Error Correction; OFDM; ADC; Frequency Selective Fading

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	J. G. Proakis, “Digital Communications,” McGraw Hill, New York, 2001.
[2]	D. Tse and P. Viswanath, “Fundamentals of Wireless Communication,” Cambridge University Press, New York, 2005. http://dx.doi.org/10.1017/CBO9780511807213
[3]	T. Rappaport, et al., “Wirelss Comunications: Principles and Practice,” Prentice Hall PTR, New Jersey, 2002.
[4]	K. Fazel and S. Kaiser, “Multi-Carrier and Spread Spectrum Systems,” Wiley, Hoboken, 2003. http://dx.doi.org/10.1002/0470871385
[5]	M. Gast, “801.11 Wireless Networks: The Definitive Guide,” O’Reilly Media Inc., Sebastopol, 2005.
[6]	J. Bingham, “Multicarrier Modulation for Data Transmission: An Idea Whose Time Has Come,” IEEE Communications Magazine, Vol. 28, No. 5, 1990, pp. 5-14. http://dx.doi.org/10.1109/35.54342
[7]	J. Cioffi, “A Multicarrier Primer,” ANSI T1E1, Vol. 4, 1991, pp. 99-157.
[8]	R. G. Gallager, “Information Theory and Reliable Communication,” John Wiley & Sons, Inc., New York, 1968.
[9]	M. Bossert, “Channel Coding for Telecommunications,” John Wiley & Sons, New York, 1999.
[10]	A. Carlson, “Communication System,” McGraw-Hill New York, 1975.
[11]	IEEE, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, High-Speed Physical Layer in the 5GHz Band (IEEE 802. 11a Standard, Part 11),” 1999.
[12]	IEEE, “Draft Standards for wireless LAN Medium Access Control (MAC) and Physical Layers (PHY) Specifications, Enhancements for Higher Throughput (IEEE 802.11n Standard, Part 11),” 2007.
[13]	“Digital Video Broadcasting (DVB): Framing Structure, Channel Coding and Modulation for Digital Terrestrial Television,” European Telecommunications Standards Institute, ETSI EN 300 744, V.1.5.1, 2004.
[14]	“Digital Video Broadcasting (DVB); Transmission System for Handheld Terminals (DVB-H),” European Telecommunications Standards Institute, 2004.
[15]	“Framing Structure, Channel Coding and Modulation for A Second Generation Digital Terrestrial Television Broadcasting System (DVB-T2),” European Telecommunications Standards Institute, 2008.
[16]	B. Nauta, E. A. M. Klumperink, “Systematic Comparison of HF CMOS Transconductors,” IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, Vol. 50, No. 10, 2003, pp. 728-741.
[17]	B. Murmann and B. Boser, “Digital Assisted Pipeline ADCs: Theory and Implementation,” Kluwer Academic Publisher, Norwell, 2004.
[18]	X. Shao and C. H. Slump, “A Novel Cross Coding Scheme for OFDM Systems,” IEEE Information Theory Workshop (ITW), Taormina, 11-16 October 2009, 5 Pages.
[19]	P. S. Medbo, “Channel Models for HIPERLAN/2,” ETSI/ BRAN, No. 3ERI085R, 1998.
[20]	V. Erceg, L. Schumacher, P. Kyritsi et al., “TGn channel Models,” IEEE 802.11 Document 802.11-03/940r4, 2004.
[21]	R. Prasad, M. Rahman and S. Das, “Single-Band MultiCarrier MIMO Transmission for Broadband Wireless Systems,” River Publisher, Aalborg, 2009.
[22]	D. MacKay, “Information Theory, Inference and Learning Algorithms,” Cambridge University Press, Cambridge, 2003.
[23]	D. Mackay, “Fountain Codes,” IEE Communications, Vol. 152, No. 6, 2005, pp. 1062-1068. http://dx.doi.org/10.1049/ip-com:20050237
[24]	M. Mitzenmacher, “Digital Fountains: A Survey and Look Forward,” IEEE Information Theory Workshop, San Antonio, October 2004, pp. 271-276.
[25]	M. Luby, “LT Codes,” Proceedings of the 43rd Annual IEEE Symposium on Foundations of Computer Science, 2002, pp. 271-282.
[26]	X. Shao, R. Schiphorst and C. H. Slump, “Opportunistic Error Correction Layer for WLAN Applications,” Proceedings of the 4th IEEE International Conference on Wireless Communications, Networking and Mobile Computing, Dalian, 12-14 October 2008, 5 Pages. -
[27]	X. Shao, R. Schiphorst and C. H. Slump, “An Opportunistic Error Correction Layer for OFDM Systems,” EURASIP Journal on Wireless Communications and Networking, Vol. 2009, 2009, 10 Pages. http://dx.doi.org/10.1155/2009/750735
[28]	Y. Kou, S. Lin and M. Fossorier, “Low-Density ParityCheck Codes Based on Finite Geometries: A Rediscovery and New Results,” IEEE Transactions on Information Theory, Vol. 47, No. 7, 2001, pp. 2711-2736. http://dx.doi.org/10.1109/18.959255
[29]	H. S. Cronie, F. W. Hoeksema and C. H. Slump, “A CSPBased Processing Architecture for a Flexible MIMOOFDM Testbed,” Proceedings of the Communications Process Architectures Symposium, Enschede, 2003, pp. 225-233.
[30]	T. Schmidl and D. Cox, “Robust Frequency and Timing Synchronization for OFDM,” IEEE Transactions on Communications, Vol. 45, No. 12, 1997, pp. 1613-1621. http://dx.doi.org/10.1109/26.650240
[31]	K. Akita, R. Sakata and K. Sato, “A Phase Compensation Scheme Using Feedback Control for IEEE 802.11a Receiver,” IEEE 60th Vehicular Technology Conference, Vol. 7, 2004, pp. 4789-4793.