Evaluation of New Trellis Coded Modulation Schemes for Nextage Mobile Communications

提出了一种新的串联栅格编码调制（TCM）设计方法，即匹配设计方法。传统的串联中医大多采用最大化最小平方欧几里得自由距离d^2_e的中医设计。采用匹配设计方法，使d^2_ (t)代替d^2_ (e)最大化，其中d^2_ (t)为外码具有t误差校正能力时的有效最小平方欧氏距离（MSED）。有效MSED由端接中药的欧几里得/汉明（E/H）关节重量分布导出。新的二维（2D）代码类别是通过计算机搜索找到的。在有效MSED码或有效多重码的性能指标下，这些码作为内码时优于Ungerboeck码等传统码。

A new design method, which is referred to as the matched design method, for concatenated trellis-coded modulation (TCM) is presented. Most of the conventional concatenated TCM employs TCM designed by maximizing the minimum squared Euclidean free distance, d^2_e. With the matched design method, we maximize d^2_ (t) instead of d^2_e, where d^2_ (t) is the effective minimum squared Euclidean distance (MSED) when the outer code has a t-error correcting capability. The effective MSED is derived from the Euclidean/Hamming (E/H) joint weight distribution of terminated TCM.The new classes of 2-dimensional (2D) codes are found by a computer search. Under the performance measures of the effective MSED or the effective multiplicity, these codes are superior to the conventional codes such as the Ungerboeck's codes when those are used as an inner code.