线性优先级不等差保护LT码的设计

LT码作为一种无码率的编码，能显著地提高网络数据吞吐量。在不同优先级的网络数据传输中，不等差保护（ UEP）是一种必要的方法。所以，设计一个性能良好的具有不等差错保护功能的LT码有很大的应用价值。文中设计了一类具有线性优先级不等差保护特性的LT码（ UEP-LT）。也就是说，对数据层的保护水平是线性分布的。提出的UEP-LT码能以极低的译码开销恢复大多数高优先级的数据。同时，这种UEP-LT码在合理的译码开销下具有比等差保护（ EEP）低的误码率，更好地满足了多媒体传输中对不等差错保护的要求。

Design of UEP-LT Codes with Linear Priorities

LT code,as a rateless code,can dramatically enhance the network throughput. Unequal Error Protection （ UEP） is a necessary method for data transmissions in a network with various priorities. Therefore,to design a LT code having good performance using unequal error protection has great value. In this paper,design a class of LT codes with the UEP propensities （ UEP-LT） . The designed UEP-LT codes will have linear priorities. That is,the protection levels of data layers are linearly distributed. The proposed UEP-LT codes can re-cover most of high priority data with extremely low decoding overhead. Also,the UEP-LT codes have a better Bit Error Rate （ BER） performance than the Equal Error Protection （ EEP） LT codes with a reasonable overhead. So,it can meet the requirement of multimedia transmission for unequal error protection.