Title :
16-level circular QAM transmissions over a Rayleigh fading channel
Author :
Webb, W.T. ; Steele, R.
Author_Institution :
Dept. of Electron. & Comput. Sci., Southampton Univ., UK
Abstract :
Techniques to improve the BER performance of 16-level QAM transmissions over Rayleigh fading channels are presented. Differential encoding, and a circular star constellation rather than the conventional square one is employed at the transmitter, while oversampling techniques combined with the prediction of the received signal envelope are used at the receiver. These procedures considerably enhance the BER performance. Whereas the BER of conventional 16-level QAM has a residual BER of 7×10-2, the enhancement procedures yield BERs of 2×10-2, 3×10-3 and 6×10-4 at channel SNRs of 15, 25 and 35 dB, respectively
Keywords :
amplitude modulation; encoding; fading; telecommunication channels; 15 dB; 16 level circular QAM; 16-QAM; 25 dB; 35 dB; BER performance; Rayleigh fading channel; SNR; circular star constellation; differential encoding; oversampling techniques; received signal envelope; receiver; transmitter;
Conference_Titel :
Multi-Level Modulation Techniques and Point-to-Point and Mobile Radio, IEE Colloquium on
Conference_Location :
London
