8 State Rate 2/3 TCM code design for fading channel

Abstract

In designing of any digital communication system, coding and modulation are generally treated as two independent functions. The role of modulator and demodulator is restricted primarily to convert an analog waveform channel to a discrete channel and the role of encoder and decoder is to correct the errors those occurred in this discrete channel. To achieve the higher performance, code rate is lowered and the redundancy in the code increased at the cost of bandwidth expansion. This code can be integrated with the expanded bandwidth efficient signal set so as to utilize the redundancy resulted from such an expansion in order to avoid bandwidth expansion. The convolutional code when integrated with a bandwidth efficient modulation scheme is termed as Trellis Coded Modulation (TCM). TCM is a bandwidth efficient transmission scheme that can achieve high coding gain by integrating coding and modulation. It was discovered in the late 1970s and is presently used in many systems for modern information transmission. In this paper, a new scheme has been proposed for designing 8 State Rate 2/3 TCM code for fading Channel.