Diversity Cutoff Rate Evaluation of the Rayleigh and Rician Fading Channels

This paper presents expressions for the cutoff rate R
0
diversity transmission over the Rayleigh and Rician fading channels with
M
-ary orthogonal signaling. These expressions include the unquantized R
0
for
D
-fold diversity, which upper bounds the channel performance, and hard decision and four- and eight-level soft decision quantized R
0
expressions. Tradeoffs between
D
and the number of quantization levels for equivalent performance are presented for the unquantized and quantized channels. These tradeoffs illustrate the reduction in signal energy, system bandwidth, and system complexity by increasing the number of quantization levels, thereby allowing a reduction in
D
.