A Spectrally Efficient Communication System: A 16-PSK Trellis Coded Modulation System Utilizing a Quantized Euclidean Decoder

Abstract

Quantization of signal set vectors [1,2] could reduce the processing time required to apply the maximum likelihood decoding algorithm of Viterbi [3], to data encoded by a trellis coded modulation (TCM) scheme of the kind proposed by Ungerboeck [4]. Simulations have been performed to determine the effect of different degrees of circular quantization on TCM, using 8-PSK and 16-PSK signal sets, combined with a four state convolutional code. It was found that circular quantization produces good results when 2 or 3 quantization points are placed between signal set vectors.