The Tight Bound for the Number of Pilots in Channel Estimation for OFDM Systems

Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver. Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI. Use of pilot symbols for channel estimation, introduces overhead and it is desirable to keep the number of pilot symbols as minimum as possible. This paper introduces a new tight bound for the number of pilots in channel estimation using adaptive scheme in OFDM systems. We calculate the minimum number of necessary pilots using two approaches. The first approach for the number of pilots is obtained based on Doppler frequency shift estimation and the second approach is acquired based on channel length estimation using second order statistics of received signal. Finally we obtain the tight bound for the number of pilots using attained values.

[1]  Miguel Rios,et al.  On using transmission overhead efficiently for channel estimation in OFDM , 2010, IEEE Transactions on Communications.

[2]  J.A.C. Bingham,et al.  Multicarrier modulation for data transmission: an idea whose time has come , 1990, IEEE Communications Magazine.

[3]  Constant P. M. J. Baggen,et al.  Blind Estimation of Maximum Delay Spread in OFDM Systems , 2006, IEEE Vehicular Technology Conference.

[4]  Franz Hlawatsch,et al.  A compressed sensing technique for OFDM channel estimation in mobile environments: Exploiting channel sparsity for reducing pilots , 2008, 2008 IEEE International Conference on Acoustics, Speech and Signal Processing.

[5]  Xianbin Wang,et al.  Analysis and Algorithm for Non-Pilot-Aided Channel Length Estimation in Wireless Communications , 2008, IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference.

[6]  Patrick Robertson,et al.  Two-dimensional pilot-symbol-aided channel estimation by Wiener filtering , 1997, 1997 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[7]  O. Edfors,et al.  OFDM channel estimation by singular value decomposition , 1996, Proceedings of Vehicular Technology Conference - VTC.

[8]  Kyungsup Kwak,et al.  Two dimension channel estimations with reduced pilot arrangements for OFDM systems , 2009, 2009 11th International Conference on Advanced Communication Technology.

[9]  Ming-Xian Chang,et al.  Detection of OFDM Signals in Fast-Varying Channels With Low-Density Pilot Symbols , 2008, IEEE Transactions on Vehicular Technology.

[10]  Shuichi Ohno,et al.  How many known symbols are required for linear channel estimation in OFDM? , 2011, 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).

[11]  Norman C. Beaulieu,et al.  Pilot Symbol Assisted Adaptive Modulation for OFDM Systems with Imperfect Channel State Information , 2010, 2010 IEEE Global Telecommunications Conference GLOBECOM 2010.

[12]  Daesik Hong,et al.  Channel estimation approach with variable pilot density to mitigate interference over time-selective cellular OFDM systems , 2008, IEEE Transactions on Wireless Communications.

[13]  Yong-Hwan Lee,et al.  Optimum pilot pattern for channel estimation in OFDM systems , 2005, IEEE Transactions on Wireless Communications.

[14]  Jungsub Byun,et al.  Adaptive pilot utilization for OFDM channel estimation in a time varying channel , 2009, 2009 IEEE 10th Annual Wireless and Microwave Technology Conference.

[15]  W. C. Jakes,et al.  Microwave Mobile Communications , 1974 .