TCM好码在空时编码中的应用

Space-time coding with powerful TCM code

网格编码将调制器和编码器看成一个整体综合设计,使得编码后的信号序列之间有最大的欧式自由距离,它可以在不需要扩张带宽或提高功率的情况下取得更好的性能.文中介绍了网格编码(TCM)好码的简化搜索算法,并将搜索到的最小TCM好码应用于空时编码中,对空时分组编码(STBC)和级联了最小TCM好码的STBC在相同的符号发送功率、信息速率和频带利用率条件下的误比特率(BER)进行比较,验证了最小TCM好码和级联码的优良性能.

Trellis coded modulation （TCM） considers modulator and encoder as a whole and makes the Euclidian free distance between signal sequences maximum. It can achieve better performance without expanding the bandwidth or improving the power. This paper describes simplified algorithm to search for powerful TCM codes at first. Then the TCM code is applied to space-time code. Finally it compares performances of space-time block coding （STBC） with the concatenated STBC with minimal powerful TCM code in terms of bit error rate （BER） under the condition of same symbol transmit power, data rate and bandwidth efficiency. It verifies the wonderful performance of minimal powerful TCM code and the concatenated code.