Title :
A high-performance reduced-complexity GMSK demodulator
Author :
Al-Dhahir, Naofal ; Saulnier, Gary
Author_Institution :
GE Corp. Res. & Dev. Centre, Niskayuna, NY, USA
fDate :
11/1/1998 12:00:00 AM
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;
Journal_Title :
Communications, IEEE Transactions on
