Turbo码，LDPC码（低密度奇偶校验码）均具有接近Shannon限的性能，

是目前便译码研究的热点。Turbo码在低信噪比情况下的性能优于其它各种编码

方式。而LDPC码的描述简单，具有较大的灵活性，当码长足够长时具有比Turbo

码更为良好的性能，其译码复杂度低于Turbo码。-Turbo code, LDPC code (LDPC) all have close to Shannon limit performance, it is the firm' s research focus. Turbo codes at low SNR is superior to other kinds of encoding. The simple descr iption of LDPC codes with greater flexibility, when code length is long enough, have a much more favorable than the Turbo code performance, its decoding complexity than Turbo codes.