一种基于8×8非均匀星座的不等差错保护方案研究

Scheme of Unequal Error Protection Based on 8×8 Nonuniformly Spaced Constellations

针对传统等差错保护(EEP)系统不能很好保护传输数据中重要数据的缺点,提出一种基于格状编码调制(TCM)的8×8非均匀星座不等差错保护(UEP)方案,接收端采用一个软输出Viterbi译码器进行重要和不重要码流的联合译码,使接收端系统得到简化,同时还可获得一定的编码增益。仿真结果表明,该UEP方案能使重要码流相对于不重要码流有很大的编码增益,且此编码增益可通过调节非均匀星座相关参数来改变。

Aiming at the shortcoming that an equal error protection system can not protect the important data well,a scheme of the unequal error protection（UEP） designed with trellis code modulation and 8×8 nonuniformly spaced constellations is proposed.A Viterbi decoder with soft-decision output is adopted in the receiver to decode the important and less important data jointly,which not only simplifies the receiver,but also obtains more coding gain.The simulation results of this UEP scheme show that the important data can obtain much more coding gain than the less important data and the coding gain can be changed by altering relevant parameters of the constellations.