Achieving Directionality and Transmit Diversity via Integrating Beam Pattern Scanning (BPS) Antenna Arrays and OFDM

Peh Keong Teh, Seyed Alireza Zekavat

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DOI: 10.4236/wsn.2010.22024                

Abstract

In this paper, we introduce a novel merger of antenna arrays with scanning beam patterns, and Orthogonal Frequency Division Multiplexing (OFDM) systems. Controlled time varying phase shifts are applied to the antenna array elements mounted at the base station with beam patterns directed toward the desired user. This creates a small beam pattern movement called Beam Pattern Scanning (BPS). In rich scattering environments BPS creates a time varying environment leading to time diversity exploitable at the receiver enhances its probability-of-error performance. Here, we apply OFDM signals to BPS antenna arrays, and we achieve: (1) directionality, which supports Space Division Multiple Access (SDMA); and (2) a time diversity gain, which leads to high performance. We discuss the structure of the base station antenna array and the OFDM receiver that exploits time diversity. We also introduce the merger of BPS and multi-carrier OFDM (MC-OFDM) systems. In MC-OFDM each bit is transmitted over all sub-carriers after serial to parallel conversion. BPS/ MC-OFDM receiver exploits both time diversity inherent in BPS, and frequency diversity inherent in MC-OFDM transmission technique. Simulation results show high Probability-of-error performance is achie- vable via BPS/OFDM and BPS/MC-OFDM schemes comparing to the traditional OFDM and MC-OFDM, respectively. Simulations also reveal that MC-OFDM system as well as its merger with BPS is capable of mitigating large Peak-to-Average Ratio (PAPR) problem in traditional OFDM system. In addition, performance simulations with coded OFDM (COFDM) and coded MC-OFDM (MC-COFDM) and their merger with BPS are studied.

Keywords

OFDM, MC-OFDM, Antenna Array, Beam Pattern Scanning, Transmit Diversity.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. V. Nee and R. Prasad, “OFDM for wireless multimedia communications,” Artech House Publisher, Boston, MA. 2000.
[2]	S. B. Weinstein and P. M. Ebert, “Data transmission by frequency-division multiplexing using the discrete fourier transform,” IEEE Transactions on Communications, Vol. COM-19, No. 5, pp. 628–634, 1971.
[3]	L. J. Cimini and Jr., “Analysis and simulation of a digital mobile channel using orthogonal frequency division multiplexing,” IEEE Transactions on Communications, Vol. COM-33, No.7, pp. 665–675, 1985.
[4]	R. W. Chang, “Orthogonal frequency division multiplexing,” U.S. Patent 3, pp. 488–445, filed 1966, issued January 6, 1970.
[5]	Z. Wang and G. B. Giannakis, “Wireless multicarrier communications: where fourier meets shannon,” IEEE Signal Processing Magazine, Vol. 17, No. 3, pp. 29–48, May 2000.
[6]	D. A. Wiegandt, Z. Wu, and C. R. Nassar, “High- throughput, high-performance OFDM via pseudo- orthogonal carrier interferometry spreading codes,” IEEE Transactions on Communications, Vol. 51, No. 7, pp. 1123–1134, July 2003.
[7]	B. Natarajan, C. R. Nassar, S. Shattil, Z. Wu, and M. Michelini, “High performance MC-CDMA via carrier interferometry codes,” IEEE Transactions on Vehicular Technology, Vol. 50, No. 6, pp. 1344–1353, November 2001.
[8]	P. K. Teh and S. A. Zekavat, “Merging multi-carrier OFDM and beam pattern scanning smart antennas: achieving low PAPR, high performance and high directionality,” Proceedings 2003 Wireless Networking Symposium, The University of Texas at Austin, October 22–24, 2003.
[9]	Y. G. Li, J. Chuang, and N. R. Sollenberger, “Transmit diversity for OFDM systems and its impact on high-rate data wireless networks,” IEEE Journal of Selected Areas in Communications, Vol. 17, pp. 1233–1243, July 1999.
[10]	D. Agarwal, V. Tarokh, A. Naguib, and N. Seshadri, “Space-time coded OFDM for high data rate wireless communication over wideband channels,” in Proceedings 48th IEEE Vehicular Technology Conference, pp. 2232–2236, Ottawa, Canada, 18–21 May 1998.
[11]	O. Norklit, P. C. F. Eggers, and J. B. Anderson, “Jitter diversity in multipath environments,” IEEE 45th Vehicular Technology Conference, VTC’95, Vol. 2, pp. 853– 857, 25–28 July 1995.
[12]	W. C. Wong, R. Steele, B. Glance, and D. Horn, “Time diversity with adaptive error detection to combat rayleigh fading in digital mobile radio,” IEEE Transactions on Communications, Vol. COM-31, No. 3, pp. 378–387, March 1983.
[13]	S. A. Zekavat and C. R. Nassar, “Antenna arrays with oscillating beam patterns: characterization of transmit diversity using semi-elliptic coverage geometric-based stochastic channel modeling,” IEEE Transactions on Communications, Vol. 50, No. 10, pp. 1549–1556, October 2002.
[14]	S. A. Zekavat and C. R. Nassar, “Achieving high capacity wireless by merging multi-carrier CDMA systems and oscillating-beam smart antenna arrays,” IEEE Transactions on Vehicular Technology, Vol. 52, No. 4, pp. 772– 778, July 2003.
[15]	S. A. Zekavat, C. R. Nassar, and S. Shattil, “Oscillating beam adaptive antennas and multi-carrier systems: Achieving transmit diversity, frequency diversity and directionality,” IEEE Transactions on Vehicular Technology, Vol. 51, No. 5, pp. 1030 –1039, September 2002.
[16]	A. M. Sayeed and B. Azhang, “Joint multipath-doppler diversity in mobile wireless communications,” IEEE Transactions on Communications, Vol. 47, No. 1, pp. 123–132, January 1999.
[17]	J. C. Liberti, Jr., and T. S. Rappaport, “Smart antennas for wireless communications: Is-95 and third generation CDMA applications,” Prentice Hall, PTR, Upper Saddle River, NJ, 1999.
[18]	J. Fuhl, A. Kuchar, and E. Bonek, “Capacity increase in cellular PCS by smart antennas,” IEEE 47th Vehicular Technology Conference, VTC’97, Vol. 3, No. 10, pp. 1962–1966, 1997.
[19]	P. K. Teh and S. A. Zekavat, “A merger of OFDM and antenna array Beam Pattern Scanning (BPS): achieving directionality and transmit diversity,” Proceedings IEEE 37th Asilomar conference on Signals, Systems and Computers, Asilomar, CA, November 9–12, 2003.
[20]	A. Kavak, “Adaptive antenna arrays for downlink capacity increase in third generation wireless CDMA,” in IEEE Radio and Wireless Conference (RAWCON’01), pp. 77–80, Boston, MA, August 2001.
[21]	A. F. Naguib, A. Paulraj, and T. Kailath, “Capacity improvement with base-station antenna arrays in cellular CDMA,” IEEE Transactions on Vehicular Technology, Vol. 43, No. 3, pp. 691–698, August 1994.
[22]	S. A. Zekavat, C. R. Nassar, and S. Shattil, “Smart antenna spatial sweeping for combined directionality and transmit diversity,” Journal of Communications and Networks (JCN), Special Issue on Adaptive Antennas for Wireless Communications, Vol. 2, No. 4, pp. 325–330, December 2000.
[23]	J. W. C. Jakes, “Microwave mobile communications,” John Wiley, New York, NY, 1974.
[24]	J. M. Auffray and J. F. Helard “Performance of multicarrier CDMA technique combined with space-time block coding over rayleigh channel,” IEEE 7th International Symposium on Spread-Spectrum Technology, Vol. 2, pp. 348–352, 2–5 September 2002.