P－TCM在卫星移动通信信道上的性能

P-TCM Performance on Satellite Mobile Communication Channels

实用化网格编码调制（Ｐ－ＴＣＭ）方案能够利用同一芯片实现不同码率的网格码之编译码过程，其性能在加性高斯白噪声信道上与ＵｎｇｅｒｂｏｅｃｋＴＣＭ码相比差别不大。本文针对编码率为２／３的６４状态Ｐ－ＴＣＭ码，从理论上计算了在相干检测和差分检测两种情况下，该码在Ｒｉｃｉａｎ信道上和轻微遮挡的Ｒｉｃｉａｎ信道上的误比特率上、下限或渐进曲线，并且给出了相应的计算机仿真结果。结果表明，当误比特率为１０－３时，该码在上述信道上约有３．４ｄＢ～５．２ｄＢ的编码增益。

Pragmatic trellis-coded modulation(P-TCM)scheme uses the same single coder and decoder for various codes which have a performance comparable to that of Ungerboeck codes on a linear Gaussian channel.In this paper,the performance on Rician fading and light shadowed Rician fading channels of a rate 2/3,64-state P-TCM code is studied.Upper bounds,lower bounds and asymptotic approximation of bit error rate(BER)with both coherent detection and differential detection are estimated.Computer simulation results are also given. The results show that there are about 3.4～5.2 dB coding gains of this code on the above mentioned channels at BER=10-3.