TTCM schemes based on time-varying trellis approach

An efficient time-varying trellis approach is proposed for turbo trellis coded modulation (TTCM). Using a time-varying trellis, the efficient free Euclidean distance is increased, thus improving the performance of TTCM. Experimental results show that the bit error rate (BER) of the proposed time-varying TTCM is better than that of the conventional TTCM scheme. Also, compared with an eight-state time-invariant TTCM scheme, a two-state time-varying TTCM scheme can achieve nearly the same BER performance.