Fast and Flexible Software Polar List Decoders
Fast and Flexible Software Polar List Decoders
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DOI：
10.1007/s11265-018-1430-3
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发表时间：
2017-10
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通讯作者：
Mathieu Léonardon;Adrien Cassagne;Camille Leroux;C. Jégo;Louis-Philippe Hamelin;Y. Savaria
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文献类型：
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作者：
Mathieu Léonardon;Adrien Cassagne;Camille Leroux;C. Jégo;Louis-Philippe Hamelin;Y. Savaria
灵活性是现代无线通信系统中信道编码的一个重要方面。除此之外，信道解码器必须支持多种码长和码率。这种灵活性需求适用于未来5G标准中考虑用于控制信道的极性编码。本文提出了一种通用的、灵活的软件逐次取消表解码器。在不重新编译软件源代码的情况下，可以动态微调大量参数：代码长度、码率、冻结位集、穿孔模式、循环冗余检查、列表大小、解码算法类型、树修剪策略和数据量化。这种通用且灵活的SCL解码器能够探索吞吐量，延迟和解码性能之间的权衡。在通用性和灵活性的限制下，提出了几种优化方法以获得具有竞争力的解码速度。由此产生的极性列表解码器比以前的通用软件解码器快4倍，只比以前的非灵活展开解码器慢2倍。由于解码器的灵活性，完全自适应SCL算法可以很容易地实现，并且比文献中任何其他类似的解码器实现更高的吞吐量，在4.5 dB的N = 2048和K = 1723下，在单个处理器核心上高达425 Mb/s。
Flexibility is one mandatory aspect of channel coding in modern wireless communication systems. Among other things, the channel decoder has to support several code lengths and code rates. This need for flexibility applies to polar codes that are considered for control channels in the future 5G standard. This paper presents a new generic and flexible implementation of a software Successive Cancellation List (SCL) decoder. A large set of parameters can be fine-tuned dynamically without re-compiling the software source code: the code length, the code rate, the frozen bits set, the puncturing patterns, the cyclic redundancy check, the list size, the type of decoding algorithm, the tree-pruning strategy and the data quantization. This generic and flexible SCL decoder enables to explore tradeoffs between throughput, latency and decoding performance. Several optimizations are proposed to achieve a competitive decoding speed despite the constraints induced by the genericity and the flexibility. The resulting polar list decoder is about 4 times faster than previous generic software decoders and only 2 times slower than previous non-flexible unrolled decoders. Thanks to the flexibility of the decoder, the fully adaptive SCL algorithm can be easily implemented and achieves higher throughput than any other similar decoder in the literature, up to 425 Mb/s on a single processor core for N = 2048 and K = 1723 at 4.5 dB.