A high-performance reduced-complexity GMSK demodulator

Author

Al-Dhahir, Naofal ; Saulnier, Gary

Author_Institution

GE Corp. Res. & Dev. Centre, Niskayuna, NY, USA

Volume

46

Issue

11

fYear

1998

fDate

11/1/1998 12:00:00 AM

Firstpage

1409

Lastpage

1412

Abstract

A four-state adaptive maximum-likelihood sequence estimation (MLSE) Gaussian minimum-shift keying (GMSK) demodulator for modulation (BT=0.3) on AWGN channels is analyzed and simulated. This demodulator uses the linear representation of GMSK signals and achieves near-optimum BER performance. The channel-impulse response used in the MLSE demodulator is initialized to the highest energy component in the linear representation, and then adapted in a decision-directed mode to offset any performance losses incurred by initially ignoring other lower energy (and time-varying) components in the linear representation. The number of MLSE states is reduced to two, at about 0.1-dB performance loss, by implementing a whitening matched filter which concentrates most of the GMSK pulse energy in its two leading samples

Keywords

AWGN channels; Viterbi decoding; adaptive estimation; demodulators; error statistics; matched filters; maximum likelihood sequence estimation; minimum shift keying; AWGN channels; GMSK demodulator; GMSK pulse energy; Gaussian minimum-shift keying; MLSE demodulator; Viterbi algorithm; adaptive maximum-likelihood sequence estimation; channel-impulse response; decision-directed mode; four-state demodulator; high-performance reduced-complexity demodulator; linear representation; near-optimum BER performance; performance losses; whitening matched filter; AWGN channels; Bit error rate; Demodulation; GSM; Intersymbol interference; Matched filters; Maximum likelihood estimation; Narrowband; Performance loss; Viterbi algorithm;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.729380

Filename

729380