PERFORMANCE SIMULATION OF TIME-VARYING PUNCTURED TRELLIS-CODED MODULATION FOR LAND MOBILE SATELLITE CHANNELS

摘要

In this paper we described a time-varying punctured trellis-coded modulation(PTCM)for improving the transmitting speech quality over land mobile satellite channels.Performance of the land mobile satellite system(LMSS)was simulated by using time-varying PTCM schemes under multi-path fading and interference.The results show that in land mobile satellite channels,our proposed system has a coding gain of 3dB compared with the uncoded QPSK system and 1.5dB compared with optimum trellis coded 8PSK system at a SEGSNR of 9dB.