Asymptotic coding gains in multiuser systems

Author

Zhang, Xuming ; Brady, David

Author_Institution

Aware Inc., Cambridge, MA, USA

Volume

2

fYear

1995

fDate

25-28 Jul 1995

Firstpage

619

Abstract

The asymptotic multiuser coding gain (AMCG) as well as asymptotic multiuser efficiency (AME) are found for K coded asynchronous users and a variety of multiuser detectors, including optimum maximum likelihood sequence (MLS), multistage, decorrelated and conventional detectors. Since the direct sequence can be viewed as a special kind of block repetition codes, it gives zero (dB) coding gain in a power-limited application. It is shown that some block encoding schemes with (n,κ), κ>1 can provide direct-sequence spread-spectrum modulation and give a positive coding gain. These systems combined with the narrow-band signature waveforms are shown to outperform the conventional approaches with the same bandwidth expansion constraint

Keywords

block codes; code division multiple access; decoding; maximum likelihood detection; pseudonoise codes; spread spectrum communication; CDMA; MLS; asymptotic multiuser coding gain; asymptotic multiuser efficiency; bandwidth expansion constraint; block encoding; block repetition codes; coded asynchronous users; conventional detectors; decoders; decorrelated detector; direct-sequence spread-spectrum modulation; maximum likelihood sequence detector; multistage detector; multiuser detectors; multiuser systems; narrowband signature waveforms; positive coding gain; Bandwidth; Decorrelation; Detectors; Encoding; Gain; Maximum likelihood detection; Modulation coding; Multilevel systems; Narrowband; Spread spectrum communication;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1995 IEEE 45th

Conference_Location

Chicago, IL

ISSN

1090-3038

Print_ISBN

0-7803-2742-X

Type

conf

DOI

10.1109/VETEC.1995.504942

Filename

504942