Title :
Matched filter for transmission over channels with ISI employing the distribution of interference
Author :
Robler, J.F. ; Huber, Johannes B.
Author_Institution :
Inst. for Information Transmission, Erlangen-Nurnberg Univ., Erlangen, Germany
Abstract :
In this paper, we analyze the matched filter (MF) applied for transmission over channels with ISI (intersymbol interference) with the MF being matched to the convolution of the transmit pulse and the channel impulse response. When convolutional coding is applied, the distribution of occurring interference and noise is commonly assumed to be Gaussian for calculation of post-detection probabilities for a subsequent MAPSSE (maximum a-posteriori symbol-by-symbol estimation) decoder. Here, we analyze the MF when employing the actual probability density function of ISI and noise for calculation of post-detection probabilities. It turns out, that these values are much more reliable especially for high signal-to-noise ratios (SNR). Therefore, the bit error ratio after decoding can be reduced by the new scheme e.g. for the considered three tap multipath channel to 10-5 and less for high SNR whereas it remains about 10-2 for the common scheme exploiting the Gaussian assumption. The proposed scheme can also be employed to improve turbo equalization.
Keywords :
Gaussian noise; convolutional codes; dispersive channels; error statistics; intersymbol interference; matched filters; maximum likelihood decoding; maximum likelihood estimation; multipath channels; transient response; Gaussian noise; ISI; MAPSSE decoder; SNR; bit error ratio; channel impulse response; channel transmission; convolutional coding; intersymbol interference; matched filter; maximum a-posteriori symbol-by-symbol estimation; postdetection probabilities; probability density function; signal-to-noise ratios; three tap multipath channel; transmit pulse; turbo equalization; Convolution; Convolutional codes; Decoding; Gaussian noise; Intersymbol interference; Matched filters; Maximum a posteriori estimation; Multipath channels; Probability density function; Signal to noise ratio;
Conference_Titel :
Vehicular Technology Conference, 2003. VTC 2003-Spring. The 57th IEEE Semiannual
Print_ISBN :
0-7803-7757-5
DOI :
10.1109/VETECS.2003.1208872