Optimum soft decision demodulation for ISI channels

Author

Raghavan, Sreenivasa A. ; Kaplan, Gideon

Author_Institution

Comstream Corp., San Diego, CA, USA

Volume

41

Issue

1

fYear

1993

fDate

1/1/1993 12:00:00 AM

Firstpage

83

Lastpage

89

Abstract

Two different methods of soft-decision demodulation for channels with finite intersymbol interference (ISI) in the presence of additive white Gaussian noise (AWGN) are analyzed. In both schemes, the cutoff rate R₀ of the discrete channel created by the demodulator output quantization is chosen as the design criterion. Expressions for the optimal thresholds of the quantizer associated with the demodulation of binary signals are derived. Results for the channel with memory equal to one symbol duration are presented. As a special case, the (1-D) channel with soft decision demodulation is analyzed. Closed-form solutions show that a 4-b quantizer improves performance substantially in this case

Keywords

demodulation; intersymbol interference; telecommunication channels; white noise; 4-b quantizer; AWGN; ISI channels; additive white Gaussian noise; binary signals; channel with memory; closed form solutions; cutoff rate; intersymbol interference; optimal thresholds; output quantization; soft decision demodulation; AWGN; Additive white noise; Closed-form solution; Demodulation; Intersymbol interference; Maximum likelihood decoding; Memoryless systems; Pulse modulation; Pulse shaping methods; Quantization;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.212368

Filename

212368