Time-Frequency Training OFDM with High Spectral Efficiency and Improved Performance over Fast Fading Channels

Time domain synchronous OFDM (TDS-OFDM) has higher spectral efficiency than cyclic prefix OFDM (CP-OFDM), but suffers from severe performance loss over fast fading channels. In this paper, a novel transmission scheme called time-frequency training OFDM (TFT-OFDM) is proposed. The time-frequency joint channel estimation for TFT-OFDM utilizes the time-domain training sequence without interference cancellation to merely acquire the time delay profile of the channel, while the path coefficients are estimated by using the frequency-domain group pilots. The redundant group pilots only occupy about 1% of the useful subcarriers, thus TFT-OFDM still has much higher spectral efficiency than CP-OFDM by about 10%. Simulation results also demonstrate that TFT-OFDM outperforms CP-OFDM and TDS-OFDM over time-varying channels.

[1]  Geert Leus,et al.  Pilot-Assisted Time-Varying Channel Estimation for OFDM Systems , 2007, IEEE Transactions on Signal Processing.

[2]  Stefania Sesia,et al.  LTE - The UMTS Long Term Evolution, Second Edition , 2011 .

[3]  Jun Wang,et al.  Iterative padding subtraction of the PN sequence for the TDS-OFDM over broadcast channels , 2005, IEEE Transactions on Consumer Electronics.

[4]  Jian Song,et al.  Technology and standards of digital television terrestrial multimedia broadcasting [Topics in Wireless Communications] , 2010, IEEE Communications Magazine.

[5]  Sangjin Lee,et al.  Synchronization and Channel Estimation in Cyclic Postfix based OFDM System , 2006, 2006 IEEE 63rd Vehicular Technology Conference.

[6]  Hai Lin,et al.  A New Adaptive OFDM System with Precoded Cyclic Prefix for Dynamic Cognitive Radio Communications , 2011, IEEE Journal on Selected Areas in Communications.

[7]  Jintao Wang,et al.  Pilot Design and Channel Estimation for TDS-OFDM System with Transmit Diversity , 2011, IEICE Trans. Commun..

[8]  Jian Fu,et al.  A Simplified Equalization Method for Dual PN-Sequence Padding TDS-OFDM Systems , 2008, IEEE Transactions on Broadcasting.

[9]  Sheng Chen,et al.  A Novel Uplink Multiple Access Scheme Based on TDS-FDMA , 2011, IEEE Transactions on Wireless Communications.

[10]  Georgios B. Giannakis,et al.  Cyclic prefixing or zero padding for wireless multicarrier transmissions? , 2002, IEEE Trans. Commun..

[11]  Mario Huemer,et al.  Unique word prefix in SC/FDE and OFDM: A comparison , 2010, 2010 IEEE Globecom Workshops.

[12]  Jong-Tae Lim,et al.  Channel estimation and signal detection for MIMO-OFDM with time varying channels , 2006, IEEE Communications Letters.

[13]  Lajos Hanzo,et al.  OFDM and MC-CDMA for Broadband Multi-User Communications, WLANs and Broadcasting , 2003 .

[14]  Jintao Wang,et al.  Transmit Diversity for TDS-OFDM Broadcasting System Over Doubly Selective Fading Channels , 2011, IEEE Transactions on Broadcasting.