Joint Frequency-Domain Equalization and Channel Estimation Using Superimposed Pilots

SC modulations (single-carrier) with FDE (frequency-domain equalization) are promising candidates for future broadband wireless systems. These modulations allow excellent performances in severely time-dispersive channels, provided that accurate channel estimates are available at the receiver. For this purpose, pilot symbols and/or training sequences are usually multiplexed with data symbols. Since this leads to overhead and some spectral degradation, the use of superimposed pilots (i.e., pilots added to data) was recently proposed. In this paper we consider SC-FDE systems where the channel estimation is based on superimposed pilots. Since the interference levels between data and pilots might be very high, we propose an iterative receiver with joint equalization and channel estimation. Our performance results show that the use of superimposed pilots, combined with the proposed receiver, allows performances close to the case with perfect channel estimation, even for severely time-dispersive channels.

[1]  Haidong Zhu,et al.  Pilot embedding for joint channel estimation and data detection in MIMO communication systems , 2003, IEEE Communications Letters.

[2]  Rui Dinis,et al.  A Class of Iterative FDE Techniques for Reduced-CP SC-Based Block Transmission , 2006 .

[3]  Andrew C. Singer,et al.  Turbo equalization: principles and new results , 2002, IEEE Trans. Commun..

[4]  Jiann-Ching Guey,et al.  A framework for future radio access , 2005, 2005 IEEE 61st Vehicular Technology Conference.

[5]  Behrouz Farhang-Boroujeny,et al.  Added pilot semi-blind channel estimation scheme for OFDM in fading channels , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[6]  Joachim Hagenauer,et al.  Linear time and frequency domain turbo equalization , 2001, IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211).

[7]  Luc Deneire,et al.  Training sequence versus cyclic prefix-a new look on single carrier communication , 2001, IEEE Communications Letters.

[8]  David Falconer,et al.  Frequency domain equalization for single-carrier broadband wireless systems , 2002, IEEE Commun. Mag..

[9]  Desmond C. McLernon,et al.  Channel estimation using implicit training , 2004, IEEE Transactions on Signal Processing.

[10]  Robert L. Frank,et al.  Polyphase codes with good nonperiodic correlation properties , 1963, IEEE Trans. Inf. Theory.

[11]  Rui Dinis,et al.  On Broadband Block Transmission over Strongly Frequency-Selective Fading Channels , 2003 .

[12]  Nevio Benvenuto,et al.  Block iterative DFE for single carrier modulation , 2002 .

[13]  Patrick Robertson,et al.  Pilot-symbol-aided channel estimation in time and frequency , 1997 .

[14]  David C. Chu,et al.  Polyphase codes with good periodic correlation properties (Corresp.) , 1972, IEEE Trans. Inf. Theory.

[15]  R. Dinis,et al.  Comparison of two modulation choices for broadband wireless communications , 2000, VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026).

[16]  Dariush Divsalar,et al.  Turbo codes: principles and applications , 1997 .

[17]  Rui Dinis,et al.  Iterative layered space-time receivers for single-carrier transmission over severe time-dispersive channels , 2004, IEEE Communications Letters.

[18]  Rui Dinis,et al.  Channel Estimation for SC-FDE Systems Using Frequency Domain Multiplexed Pilots , 2006, IEEE Vehicular Technology Conference.