Square-QAM adaptive modulation/TDMA/TDD systems using modulation level estimation with Walsh function

Author

Otsuki, Satoshi ; Sampei, Seiichi ; Morinaga, N.

Author_Institution

Dept. of Commun. Eng., Osaka Univ.

Volume

31

Issue

3

fYear

1995

fDate

2/2/1995 12:00:00 AM

Firstpage

169

Lastpage

171

Abstract

The authors propose a square-QAM adaptive modulation/time division multiple access/time division duplex (TDMA/TDD) system for land mobile communications to achieve high quality and high bit rate transmission in both flat and frequency selective fading environments. To further improve performance, a new modulation level estimation scheme using the Walsh function and maximum likelihood (MS) estimation is also proposed. Computer simulation confirms that the proposed system gives 8 dB better performance and four times larger delay spread immunity than that of conventional QPSK systems at BER=10^-3

Keywords

Walsh functions; digital radio; error statistics; fading; land mobile radio; maximum likelihood estimation; quadrature amplitude modulation; time division multiple access; BER; TDMA; Walsh function; bit error rate; delay spread immunity; flat fading environment; frequency selective fading environment; high bit rate transmission; land mobile communications; maximum likelihood estimation; modulation level estimation; square-QAM adaptive modulation; time division duplex; time division multiple access;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19950129

Filename

362584