A Model Reduction Approach for OFDM Channel Estimation Under High Mobility Conditions

• Published in: IEEE transactions on signal processing Vol. 58; no. 4; pp. 2181 - 2193
• Main Authors: Al-Naffouri, T.Y., Islam, K.M.Z., Al-Dhahir, N., Lu, S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Broadband; Channel estimation; Channels; Complexity; Degradation; Detection, estimation, filtering, equalization, prediction; Digital video broadcasting; Doppler frequency; Exact sciences and technology; Frequency division multiplexing; Frequency domain analysis; Frequency domains; ICI; Information, signal and communications theory; Interference; Miscellaneous; model reduction; Multiplexing; OFDM; Receivers; Reduced order systems; Reduction; Signal and communications theory; Signal processing; Signal, noise; Studies; Telecommunications and information theory; Time-varying channels; WiMAX; Performance evaluation; Parameter estimation; Input signal; OFDM; Wireless telecommunication; Subcarrier; Time variation; Coherent detection; Implementation; Doppler frequency; Wide band; Channel estimation; Off line; High rate transmission; High performance; Time variable channel; Intercarrier interference; Time correlation; model reduction; Frequency domain method; Algorithm; ICI; Orthogonal frequency division multiplexing; Signal processing; Long distance transmission; Digital video broadcasting
• ISSN: 1053-587X; 1941-0476
• DOI: 10.1109/TSP.2009.2039732

Orthogonal frequency-division multiplexing (OFDM) combines the advantages of high performance and relatively low implementation complexity. However, for reliable coherent detection of the input signal, the OFDM receiver needs accurate channel information. When the channel exhibits fast time variation as it is the case with several recent OFDM-based mobile broadband wireless standards (e.g., WiMAX, LTE, DVB-H), channel estimation at the receiver becomes quite challenging for two main reasons: 1) the receiver needs to perform this estimation more frequently and 2) channel time-variations introduce intercarrier interference among the OFDM subcarriers which can degrade the performance of conventional channel estimation algorithms significantly. In this paper, we propose a new pilot-aided algorithm for the estimation of fast time-varying channels in OFDM transmission. Unlike many existing OFDM channel estimation algorithms in the literature, we propose to perform channel estimation in the frequency domain, to exploit the structure of the channel response (such as frequency and time correlations and bandedness), optimize the pilot group size and perform most of the computations offline resulting in high performance at substantial complexity reductions.