Implementation and performance of an adaptive QAM modulation-level-controlled system for land mobile communications

Author

Hamaguchi, Kiyoshi ; Kamio, Yukiyoshi ; Moriyama, Eimatsu

Author_Institution

Commun. Res. Lab., Minist. of Posts & Telecommun., Tokyo, Japan

Volume

2

fYear

1997

fDate

4-7 May 1997

Firstpage

1214

Abstract

An adaptive modulation system for land mobile communications that can select one of the quadrature amplitude modulation levels as a suitable modulation for the propagation conditions is described. The main characteristics of the system are a mode in which information cannot be transmitted under adverse propagation conditions and a buffer memory for maintaining the data transmission rate. We confirmed the basic performance of the adaptive modulation system using the equipment we developed and we found the measured performance was consistent with computer simulation results. We also found that the adaptive modulation system provided a noticeable improvement in the spectral efficiency and transmission quality

Keywords

buffer storage; land mobile radio; quadrature amplitude modulation; radiowave propagation; telecommunication control; adaptive QAM; buffer memory; computer simulation results; data transmission rate; land mobile communications; measured performance; modulation-level-controlled system; propagation conditions; quadrature amplitude modulation levels; spectral efficiency; transmission quality; Adaptive systems; Amplitude modulation; Bit rate; Computer simulation; Data communication; Fading; Mobile communication; Performance evaluation; Quadrature amplitude modulation; Quadrature phase shift keying;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1997, IEEE 47th

Conference_Location

Phoenix, AZ

ISSN

1090-3038

Print_ISBN

0-7803-3659-3

Type

conf

DOI

10.1109/VETEC.1997.600524

Filename

600524