Multirate trellis coded modulation schemes in multimedia communications

Multirate multimedia information with different quality of service may be required at the same time in future communication systems. We propose a new class of trellis coded modulation (TCM) schemes, which can carry two different rates of multimedia information using only the same signal constellation. The transmitted information bit number per symbol in the proposed TCM is not an integer and is greater than that of the conventional TCM. An interesting character of the proposed multirate TCM is that it can provide different error protection for the two information rates. We also present the design criterion and the existence of noncatastrophic multirate TCM. Some theoretical and simulation results have shown that it can provide a certain coding gain compared with the corresponding uncoded modulation schemes