Robust channel estimation for OFDM systems with rapid dispersive fading channels

Author

Li, Ye ; Cimini, Leonard J., Jr. ; Sollenberger, Nelson R.

Author_Institution

Wireless Syst. Res. Dept., AT&T Bell Labs., Red Bank, NJ, USA

Volume

46

Issue

7

fYear

1998

fDate

7/1/1998 12:00:00 AM

Firstpage

902

Lastpage

915

Abstract

Orthogonal frequency-division multiplexing (OFDM) modulation is a promising technique for achieving the high bit rates required for a wireless multimedia service. Without channel estimation and tracking, OFDM systems have to use differential phase-shift keying (DPSK), which has a 3-dB signal-to-noise ratio (SNR) loss compared with coherent phase-shift keying (PSK). To improve the performance of OFDM systems by using coherent PSK, we investigate robust channel estimation for OFDM systems. We derive a minimum mean-square-error (MMSE) channel estimator, which makes full use of the time- and frequency-domain correlations of the frequency response of time-varying dispersive fading channels. Since the channel statistics are usually unknown, we also analyze the mismatch of the estimator-to-channel statistics and propose a robust channel estimator that is insensitive to the channel statistics. The robust channel estimator can significantly improve the performance of OFDM systems in a rapid dispersive fading channel

Keywords

correlation methods; differential phase shift keying; dispersion (wave); fading; frequency division multiplexing; frequency response; frequency-domain analysis; land mobile radio; least mean squares methods; multimedia communication; parameter estimation; statistical analysis; time-domain analysis; time-varying channels; DPSK; MMSE channel estimator; OFDM modulation; OFDM system; SNR loss; channel statistics; coherent PSK; coherent phase-shift keying; differential phase-shift keying; estimator-to-channel statistics mismatch; frequency response; frequency-domain correlation; high bit rates; minimum mean-square-error; mobile radio; orthogonal frequency-division multiplexing; performance; rapid dispersive fading channels; robust channel estimation; signal-to-noise ratio; time-domain correlation; time-varying channels; tracking; wireless multimedia service; Bit rate; Channel estimation; Dispersion; Fading; Frequency division multiplexing; Frequency modulation; OFDM modulation; Phase shift keying; Robustness; Statistical analysis;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.701317

Filename

701317