Adaptive coding rate trellis-coded 8PSK system

This paper presents an adaptive coding rate trellis coded octal phase-shift keying sq stem with rates of 1/3, 1/2, 2/3, and 5/6, under the restriction of a constant transmission bit rate. where the ratio between the information bits and error-correcting redundant bits varies according to channel conditions. This system has the advantage of using a simple modem configuration. Because it has no need to change modulation type, transmitter/receiver filters, and clock and carrier recovery circuits. and it can use a convenient Read-Only-Memory table encoder. As for code design. the trellis structures and its signal assignments For rates of 1/3, 1/2, and 5/6 ale proposed and investigated. and their BER performances are estimated. As a result, when the system requirement is to keep the bit error rate of 10(-4), this system can operate at the lower Eb/No value of 1.5 dB on the reduction of transmitting information bits.