Effectiveness of Preamble Based Channel Estimation for OFDM/OQAM System

In this paper, we propose a modified preamble based channel estimation for the orthogonal frequency division multiplex/Offset QAM (OFDM/OQAM). In present of multi-path effect, the Inter Symbol Interference (ISI) always exists in the OFDM/OQAM system and the preamble based channel estimation for the conventional orthogonal frequency division multiplex with cyclic prefix (CP-OFDM) is not feasible any more. Considering the characteristic of the Extended Gaussian Function (EGF), we propose two modified preamble based channel estimation by adding guard symbols, which are located at both sides (method A) and the left side (method B) of preamble reference symbol. Compared with the CP-OFDM system, the proposed preamble based channel estimation achieves 2dB improvement. Meanwhile, method B remains the same BER performance with method A, but require less guard symbols. Therefore, method B is more feasible and effective preamble based channel estimation method for the practical OFDM/OQAM system.

[1]  Andreas F. Molisch,et al.  Nonorthogonal pulseshapes for multicarrier communications in doubly dispersive channels , 1998, IEEE J. Sel. Areas Commun..

[2]  Claude Berrou,et al.  Coded orthogonal frequency division multiplex [TV broadcasting] , 1995, Proc. IEEE.

[3]  Svante Signell,et al.  Classic OFDM Systems and Pulse Shaping OFDM/OQAM Systems , 2007 .

[4]  P. P. Vaidyanathan,et al.  Cosine-modulated FIR filter banks satisfying perfect reconstruction , 1992, IEEE Trans. Signal Process..

[5]  R. Legouable,et al.  Preamble-based channel estimation techniques for OFDM/OQAM over the powerline , 2007, 2007 IEEE International Symposium on Power Line Communications and Its Applications.

[6]  Jinfeng Du,et al.  Time frequency localization of pulse shaping filters in OFD/OQAM systems , 2007, 2007 6th International Conference on Information, Communications & Signal Processing.

[7]  Fernando Cruz-Roldán,et al.  Efficient implementation of nearly perfect reconstruction FIR cosine-modulated filterbanks , 2004, IEEE Transactions on Signal Processing.

[8]  Helmut Bölcskei,et al.  Orthogonal Frequency Division Multiplexing Based on Offset QAM , 2003 .

[9]  Pierre Siohan,et al.  Analysis and design of OFDM/OQAM systems based on filterbank theory , 2002, IEEE Trans. Signal Process..

[10]  Jean-Philippe Javaudin,et al.  Pilot-aided channel estimation for OFDM/OQAM , 2003, The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring..

[11]  Pierre Siohan,et al.  2 dB Better Than CP-OFDM with OFDM/OQAM for Preamble-Based Channel Estimation , 2008, 2008 IEEE International Conference on Communications.

[12]  Thomas Strohmer,et al.  Optimal OFDM design for time-frequency dispersive channels , 2003, IEEE Trans. Commun..

[13]  Pierre Siohan,et al.  Design techniques for orthogonal Modulated filterbanks based on a compact representation , 2004, IEEE Transactions on Signal Processing.

[14]  Helmut Bölcskei,et al.  Orthogonalization of OFDM/OQAM pulse shaping filters using the discrete Zak transform , 2003, Signal Process..

[15]  B. Floch,et al.  Coded orthogonal frequency division multiplex , 1995 .

[16]  Nicola Laurenti,et al.  Efficient implementations and alternative architectures for OFDM-OQAM systems , 2001, IEEE Trans. Commun..

[17]  X.-D. Zhang,et al.  Hexagonal Multicarrier Modulation: A Robust Transmission Scheme for Time-Frequency Dispersive Channels , 2007, IEEE Transactions on Signal Processing.