3GPP MBMS中Raptor码的改进译码算法研究

An Improved Decoding Algorithm of Raptor Codes in 3GPP MBMS

根据第三代合作伙伴计划(3rd Generation Partnership Project,3GPP)多媒体广播多播业务(Multimedia B ro adc ast/M u lticas t S erv ice,M BM S)标准提出了一种改进的Ra pto r码译码算法。该算法与3G PP译码算法的不同之处有三个部分,前两处是对译码步骤的某些部分进行了修改,使得译码时间缩短;另一处是在3GPP方案中,一旦译码失败则必须接收新的编码符号重新开始,但文章提出的算法只需对新的编码符号做一些简单操作即可继续译码直至成功。因此,该算法大量减小了冗余的计算,提高了译码的效率,同时又具有和原算法一致的译码性能。

This paper proposes an improved decoding algorithm based on 3GPP MBMS Standard. The algorithm has three differences from 3GPP decoding algorithm. The former two are the modification of the decoding steps, which shortens the decoding time. Another is that you must receive new encoding symbols to restart decoding process once the decoding process fails in 3GPP, while the algorithm we present just needs to do some simple operations to new received encoding symbols and then we can continue decoding process until it succeeds. Therefore, this algorithm greatly reduces the redundant calculation and makes the efficiency of decoding improved, and meanwhile has the consistent performance with original algorithm.