香农极限

自1993年以来，编码界就对一种新的纠错turbo码投以极大上的新趣。Turbo码的误码率非常接近香农极限。

Since 1993 , much interest of the coding community has focused around turbo codes , whose bit error rate is very close to Shannon limit .

通常的，数字电视系统采用的信道编码方案为RS码或卷积码，或二者的级联码，它的纠错性能与香农极限相比，仍有一定的距离。

Conventionally , DTV systems adopt coding schemes such as RS or convolutional codes , or concatenated codes , where the error correction performance is still quite far away from the Shannon limit .

低密度奇偶校验（LowDensityParityCheck：LDPC）码具有接近香农极限的优异纠错性能，近年来受到广泛关注。

Low Density Parity Check ( LDPC ) codes can achieve excellent error-correcting performance close to the benchmark predicted by the Shannon theory , and it attracts much more attention in recent years .

作为信道纠错码的一种，低密度奇偶校验码（LDPC）以其较低的译码复杂度和逼近香农极限的良好性能成为当今信道编解码领域最瞩目的研究热点。

Low-density Parity-Check ( LDPC ) code is distinguished in channel encoding and decoding realm for its low implementation complexity and near-to-Shannon-limit performance .

为了满足高速、高质量业务的传输要求，TD-SCDMA协议标准采用性能接近香农极限的Turbo码作为主要的信道编码技术。

In order to meet the high speed , high quality business transmission requirements , td-scdma agreement standard use Turbo code which has a performance is close to the Shannon limits as the main channel coding technology .

Turbo码代表着当今世界上最先进的信道编码技术，因为它具有极其逼近香农极限的纠错性能，所以Turbo码一出现便吸引了通信领域无数专家学者的关注与研究。

Turbo code represents the most advanced channel coding technology in the world nowadays . Because its error-correcting performance is very closely to the Shannon limit , Turbo code attracting concern and study of countless experts and scholars in communication domain once it appears .

构造接近香农极限的低密度校验码

Construction of Low-Density Parity-Check Code Approaching the Shannon Limit

以本文为例，采用的咬尾卷积码编码器经过交织器交织后，最大程度的实现了随机性编码，这就非常符合逼近香农极限的条件。

This article , for example , using the tail biting convolution code encoder after interleaving make out the greatest degree of randomness coding , which is consistent with the conditions of approaching the Shannon limit .

它具有如下诸多优点：描述简单、较低的译码复杂度、可以并行实现、使用相对灵活、错误平台较低、可以逼近香农极限等。

It has the following many advantages : simple description , the low decoding complexity , parallel implementation , the use of a relatively flexible , low error platform , may be approaching the Shannon limit and so on .

同时对其译码性能进行了仿真分析，结果表明，在特定的参数条件下，其误码率接近香农极限，验证了其优异的纠错译码性能。

At the same time , the simulation analysis on the decoding performance of Turbo codes was given , and the results show that under the certain conditions , Turbo codes approaches the theoretical Shannon limit , which proves its excellent performance of decoding .

Turbo码表现出了接近香农理论极限的优异性能，主要是由于它采用了迭代译码的思想。

Turbo code demonstrates excellent performance of nearing the Shannon limit , mainly because it has adopted the thought of iterative decoding .

虽然这两种码的纠错性能已逼近香农信道容量的极限，但其较高的编译码复杂度和较大的处理时延仍然限制了它们的应用。

The performance of the two error-correcting codes has been close to the Shannon limit , however , the high decoding complexity and large processing delay restricts the application of the two codes .

本论文在信息论的信道容量及香农编码理论的基础上，引入了接近香农理论极限的信道编码Turbo码。

On the basis of channel capacity and shannon limit of information theory , we introduce the Turbo codes which obtain the near capacity performance .