Bandwidth efficient QAM schemes for Rayleigh fading channels

Author

Webb, W.T. ; Hanzo, L. ; Steele, R.

Author_Institution

Dept. of Electron. & Comput. Sci., Southampton Univ., UK

Volume

138

Issue

3

fYear

1991

fDate

6/1/1991 12:00:00 AM

Firstpage

169

Lastpage

175

Abstract

Techniques to improve the BER performance of 16-level QAM transmission over Rayleigh fading channels for PCN systems are presented. Simulations were carried out with a carrier frequency of 1.9 GHz, data rate of 64 kbit/s and mobile speed of 30 mph. The residual BER was reduced by over an order of magnitude, by introducing a circular constellation coupled with differential amplitude and phase encoding, compared with a square QAM constellation. When an oversampling and interpolation technique was combined with the circular constellation with differential encoding another order of magnitude reduction in residual BER was obtained. Decreasing the data throughput to 48 kbit/s using a ³/₄ rate RS(60,44,12) code, 16-level QAM, interleaved over 40 ms yielded a BER of 10^-6 for channel SNRs above 25 dB.<>

Keywords

amplitude modulation; encoding; error correction codes; error statistics; fading; personal communication networks; telecommunication channels; 1.9 GHz; 16-level QAM transmission; 30 mph; 48 kbit/s; 64 kbit/s; BER performance; PCN systems; RS(60,44,12) code; Rayleigh fading channels; Reed Solomon code; UHF; bandwidth efficient QAM schemes; circular constellation; differential encoding; interleaving; interpolation; oversampling; personal communication networks;

fLanguage

English

Journal_Title

Communications, Speech and Vision, IEE Proceedings I

Publisher

iet

ISSN

0956-3776

Type

jour

Filename

87862