High Diversity Transceiver for Low Power Differentially Encoded OFDM System

  • Nadeem, Faisal (Department of Electronics, Quaid-i-Azam University) ;
  • Zia, Muhammad (Department of Electronics, Quaid-i-Azam University) ;
  • Mahmood, Hasan (Department of Electronics, Quaid-i-Azam University) ;
  • Bhatti, Naeem (Department of Electronics, Quaid-i-Azam University) ;
  • Haque, Ihsan (Department of Electronics Engineering, International Islamic University)
  • Received : 2015.01.06
  • Accepted : 2015.09.30
  • Published : 2016.02.01


In this work, we investigate differentially encoded blind transceiver design in low signal-to-noise ratio (SNR) regimes for orthogonal frequency-division multiplexing (OFDM) signaling. Owing to the fact that acquisition of channel state information is not viable for short coherence times or in low SNR regimes, we propose a time-spread frequency-encoded method under OFDM modulation. The repetition (spreading) of differentially encoded symbols allows us to achieve a target energy per bit to noise ratio and higher diversity. Based on the channel order, we optimize subcarrier assignment for spreading (along time) to achieve frequency diversity of an OFDM modulated signal. We present the performance of our proposed transceiver design and investigate the impact of Doppler frequency on the performance of the proposed differentially encoded transceiver design. To further improve reliability of the decoded data, we employ capacity-achieving low-density parity-check forward error correction encoding to the information bits.


  1. M. Lott, "Comparison of Frequency and Time Domain Differential Modulation in an OFDM System for Wireless ATM," IEEE Veh. Technol. Conf., Houston, TX, USA, vol. 2, May 16-20, 1999, pp. 877-883.
  2. R. Hermann and T. May, "Comparison of PSK and DPSK Modulation in a Coded OFDM System,'' IEEE Veh. Technol. Conf., Phoenix, AZ, USA, vol. 2, May 4-7, 1997, pp. 870-874.
  3. N.A.B. Svensson, "On Differentially Encoded Star 16QAM with Differential Detection and Diversity," IEEE Trans. Veh. Technol., vol. 44, no. 3, Aug. 1995, pp. 586-593.
  4. D. Tse and P. Viswanath, "Fundamentals of Wireless Communication," Cambridge, England: Cambridge University Press, 2005.
  5. D. Divsalar and M.K. Simon, "Multiple-Symbol Differential Detection of MPSK," IEEE Trans. Commun., vol. 38, no. 3, Mar. 1990, pp. 300-308.
  6. L. Hanzo et al., "MIMO-OFDM for LTE, WIFI, and WiMAX: Coherent versus Non-coherent and Cooperative Turbo Transceivers," West Sussex, England: John Willey & Sons, 2010.
  7. C. Berrou and A. Glavieux, "Near Optimum Error Correcting Coding and Decoding: Turbo-Codes," IEEE Trans. Commun., vol. 44, no. 10, Oct. 1996, pp. 1261-1271.
  8. R. Gallager, "Low-Density Parity-Check Codes," IRE Trans. Inf. Theory, vol. 8, no. 1, Jan. 1962, pp. 21-28.
  9. M. Zia et al., "Bandwidth-Efficient Selective Retransmission for MIMO-OFDM Systems," ETRI J., vol. 37, no. 1, Feb. 2015, pp. 66-76.
  10. M. Zia et al., "Selective HARQ Transceiver Design for OFDM System," IEEE Commun. Lett., vol. 17, no. 12, Oct. 2013, pp. 2229-2232.
  11. A. Ramesh, A. Chockalingam, and L.B. Milstein, "Performance of Noncoherent Turbo Detection on Rayleigh Fading Channels," IEEE Global Telecommun. Conf., San Antonio, TX, USA, vol. 2, Nov. 25-29, 2001, pp. 1193-1198.
  12. H. Tatsunami, K. Ishibashi, and H. Ochiai, "On the Performance of LDPC Codes with Differential Detection over Rayleigh Fading Channels," IEEE Veh. Technol. Conf., Melbourne, Australia, May 7-10, 2006, pp. 2388-2392.
  13. E. Mo, P.Y. Kam, and M.A. Armand, "LLR Metrics for LDPC Codes with Quadrature Differential PSK Transmission, and their Performances," IEEE Int. Symp. Inf. Theory its Appl., Auckland, New Zealand, Dec. 7-10, 2008, pp. 1-6.
  14. H. Rohling and V. Engels, "Differential Amplitude Phase Shift Keying (DAPSK) - A New Modulation Method for DTVB," IET Int. Broadcast. Conf., Amsterdam, Netherlands, Sept. 14-18, 1995, pp. 102-108.
  15. L. Lampe, R. Schober, and R. Fischer, ''Noncoherent and Coded OFDM Using Decision-Feedback Demodulation and Diversity,'' Proc. Int. OFDM Workshop, Hamburg, Germany, Sept. 2000, pp. 1-5.
  16. M. Luise, R. Reggiannini, and G.M. Vitetta, "Blind Equalization/ Detection for OFDM Signals over Frequency-Selective Channels," IEEE J. Sel. Areas Commun., vol. 16, no. 8, Oct. 1998, pp. 1568-1578.
  17. L. Lampe et al., "Multiple-Symbol Differential Sphere Decoding," IEEE Trans. Commun., vol. 53, no. 12, Dec. 2005, pp. 1981-1985.
  18. V. Tarokh and H. Jafarkhani, "A Differential Detection Scheme for Transmit Diversity," IEEE J. Sel. Areas Commun., vol. 18, no. 7, July 2000, pp. 1169-1174.
  19. S. Poorkasmaei and H. Jafarkhani. "Asynchronous Orthogonal Differential Modulation for Multiple Access Channels," IEEE Trans. Wireless Commun. Dec. 2014, pp. 1-12. (arXiv preprint)
  20. J. Proakis and M. Salehi, "Digital Communications," NY, USA: McGraw-Hill, 2007.
  21. Z. Liu, Y. Xin, and G.B. Giannakis, "Linear Constellation Precoding for OFDM with Maximum Multipath Diversity and Coding Gains," IEEE Trans. Commun., vol. 51, no. 3, Mar 2003, pp. 416-427.
  22. X. Zhu and J. Xue, "On the Correlation of Subcarriers in Grouped Linear Constellation Precoding OFDM Systems over Frequency Selective Fading," IEEE Veh. Technol. Conf., Melbourne, Australia, May 7-10, 2006, vol. 3, pp. 1431-1435.
  23. X. Wang et al., ''Efficient Non-pilot-aided Channel Length Estimation for Digital Broadcasting Receivers,'' IEEE Trans. Broadcast., vol. 55, no. 3, June 2009, pp. 633-641.
  24. V.T. Nam, P.Y. Kam, and Y. Xin, "LDPC Codes with BDPSK and Differential Detection over Flat Rayleigh Fading Channels,'' IEEE Conf. Global Telecommun., Washington, DC, USA, Nov. 26-30, 2007, pp. 3245-3249.