Title :
Joint blind estimation of channel and data symbols in OFDM
Author :
Song, Yu ; Roy, Sumit ; Akers, Lex A.
Author_Institution :
MathWorks, Natick, MA, USA
Abstract :
In OFDM transmission over an FIR channel, an accepted method for combating the resultant ISI is via addition of a cyclic prefix whose length exceeds the the FIR channel duration, to each transmitted data block. This converts the time-domain linear convolution of the FIR channel to cyclic convolution, or effectively, to a multiplicative channel distortion in the frequency domain. The (frequency-domain) multiplicative channel is easily estimated by use of a training sequence thereby greatly reducing the channel equalization complexity at the cost of reduction in spectral efficiency due to the cyclic prefix. This paper explores OFDM systems without cyclic prefix and training sequence. By adopting virtual carriers and exploiting the finite alphabet property of the input symbols, a blind technique for joint estimation of channel and data symbols is developed. While this restores the spectral efficiency, it is achieved at the expense of increased processing complexity at the receiver
Keywords :
OFDM modulation; blind equalisers; convolution; intersymbol interference; parameter estimation; telecommunication channels; time-domain analysis; FIR channel duration; ISI; OFDM transmission; channel equalization complexity; channel estimation; cyclic convolution; data symbols estimation; finite alphabet property; frequency domain; frequency-domain multiplicative channel; input symbols; joint blind estimation; multiplicative channel distortion; processing complexity; receiver; spectral efficiency; time-domain linear convolution; transmitted data block; virtual carriers; Baseband; Convolution; Data engineering; Decision feedback equalizers; Discrete Fourier transforms; Filtering; Finite impulse response filter; Frequency domain analysis; Lakes; OFDM modulation;
Conference_Titel :
Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5718-3
DOI :
10.1109/VETECS.2000.851415