Improving energy efficiency of partial response signals by using coded modulation

Abstract

One of the most popular approaches to improving bandwidth efficiency is the use of signals with inter-symbol interference (ISI). In this paper bandwidth-efficient partial response signals (PRS) are analyzed in combinations with 4-QAM, 8-QAM and 16-QAM signal constellations and recursive systematic convolutional codes. We simulated transmission of encoded data through AWGN channel using the optimal PRS, each pulse shape gave maximal free Euclidean distance for chosen constellation and bandwidth. Also, we employed iterative receiver (or turbo equalizer) for detection and decoding of these signals. It is shown that the coded PRS exceed trellis-coded modulation and reach turbo trellis-coded modulation in bandwidth and energy characteristics.