A Null-Subcarrier-Aided Reference Symbol Mapping Scheme for 3GPP LTE Downlink in High-Mobility Scenarios

In this paper, a new reference symbol (RS) mapping scheme for the Third-Generation Partnership Project (3GPP) long-term evolution (LTE) and LTE-Advanced (LTE-A) downlink is proposed to improve channel estimation performance in high-mobility communication scenarios. The proposed scheme employs null subcarriers to guard RSs, which helps mitigate the effect of intercarrier interference (ICI) on subcarriers carrying RSs. Additionally, the proposed scheme allows the ICI gain parameters to be estimated via a simple frequency-domain estimator. Modified Cramer-Rao bound (MCRB) expressions are derived for the proposed scheme, as well as for the conventional RS mapping scheme defined in the 3GPP LTE and LTE-A standards to compare their performance at high mobile user speeds. These bounds, together with mean square errors obtained from simulations, reveal superior performance achieved by the proposed scheme in high-mobility scenarios. Additionally, at high mobile user speeds, the proposed scheme offers significant bit-error-rate (BER) performance improvement over the standard RS mapping.

[1]  Jia-Chin Lin.  Least-Squares Channel Estimation for Mobile OFDM Communication on Time-Varying Frequency-Selective Fading Channels , 2008, IEEE Transactions on Vehicular Technology.

[2]  Pei-Yun Tsai,et al.  OFDM Baseband Receiver Design for Wireless Communications , 2007 .

[3]  Gordon L. Stuber,et al.  Principles of mobile communication (2nd ed.) , 2001 .

[4]  Umberto Mengali,et al.  The modified Cramer-Rao bound in vector parameter estimation , 1998, IEEE Trans. Commun..

[5]  Donald C. Cox,et al.  ICI mitigation for pilot-aided OFDM mobile systems , 2005, IEEE Transactions on Wireless Communications.

[6]  Tzi-Dar Chiueh,et al.  One-dimensional interpolation based channel estimation for mobile DVB-H reception , 2006, 2006 IEEE International Symposium on Circuits and Systems.

[7]  Erik Dahlman,et al.  4G: LTE/LTE-Advanced for Mobile Broadband , 2011 .

[8]  Sau-Hsuan Wu,et al.  The Modified Bayesian Cramer-Rao Bound for MIMO Channel Tracking , 2009, 2009 IEEE International Conference on Communications.

[9]  Naofal Al-Dhahir,et al.  Coherent and Differential ICI Cancellation for Mobile OFDM with Application to DVB-H , 2008, IEEE Transactions on Wireless Communications.

[10]  Carlos H. Muravchik,et al.  Posterior Cramer-Rao bounds for discrete-time nonlinear filtering , 1998, IEEE Trans. Signal Process..

[11]  G. Matz,et al.  Recursive MMSE estimation of wireless channels based on training data and structured correlation learning , 2005, IEEE/SP 13th Workshop on Statistical Signal Processing, 2005.

[12]  R. W. Miller,et al.  A modified Cramér-Rao bound and its applications (Corresp.) , 1978, IEEE Trans. Inf. Theory.

[13]  Jose F. Monserrat,et al.  MAC Layer Performance of Different Channel Estimation Techniques in UTRAN LTE Downlink , 2009, VTC Spring 2009 - IEEE 69th Vehicular Technology Conference.

[14]  Brian L. Evans,et al.  Sinusoidal Modeling and Adaptive Channel Prediction in Mobile OFDM Systems , 2008, IEEE Transactions on Signal Processing.

[15]  Naofal Al-Dhahir,et al.  Receiver Design for Mobile OFDM with Application to DVB-H , 2006, IEEE Vehicular Technology Conference.

[16]  Witold A. Krzymien,et al.  Null Sub-Carrier Aided Reference Symbol Mapping for Improved Channel Estimation in 3GPP LTE Downlink , 2010, 2010 IEEE 71st Vehicular Technology Conference.

[17]  Marc Moeneclaey,et al.  On the true and the modified Cramer-Rao bounds for the estimation of a scalar parameter in the presence of nuisance parameters , 1998, IEEE Trans. Commun..

[18]  Laurent Ros,et al.  Analytical Analysis of Bayesian CramÉr–Rao Bound for Dynamical Rayleigh Channel Complex Gains Estimation in OFDM System , 2009, IEEE Transactions on Signal Processing.

[19]  N. Al-Dhahir,et al.  Reduced-complexity hybrid time/frequency channel estimation for DVB-H , 2007, 2007 IEEE Sarnoff Symposium.

[20]  Sailes K. Sengijpta.  Fundamentals of Statistical Signal Processing: Estimation Theory , 1995 .

[21]  Shengwei Hou,et al.  High mobility orthogonal frequency division multiple access channel estimation using basis expansion model , 2010, IET Commun..