RCA analysis of the polar codes and the use of feedback to aid polarization at short blocklengths
RCA analysis of the polar codes and the use of feedback to aid polarization at short blocklengths
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极化码的 RCA 分析以及使用反馈来帮助短块长度极化
DOI：
10.1109/isit.2015.7282664
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
R. Wesel
中科院分区：
文献类型：
--
作者：
K. Vakilinia;D. Divsalar;R. Wesel
本文使用互惠通道近似（RCA）的扩展，通过分析与信息位相关的对数比率（LLR）的概率密度函数（P.D.F），准确有效地预测极性代码的帧错误率（FER）性能。反馈方案使用RCA与重复编码系统一起预测LLR的P.D.F，以将目标FER所需的区块长度降低16倍。使用RATE-0.5 128位极性代码作为最初传输的代码，具有反馈的系统的FER是通过理论分析获得的，并通过模拟验证。包括额外的增量传输包括反馈系统的平均区块长度为137.55位，速率为0.4653。没有反馈，需要具有区块长度2048的极性代码才能以可比的速率获得可比的FER。直觉上，反馈允许极地代码在初始传输中使用较少的冷冻位，然后使用重复代码来提供所需的可靠性，以解决反馈确定的不可靠的未透明位。
This paper uses an extension of Reciprocal Channel Approximation (RCA) to accurately and efficiently predict the frame error rate (FER) performance of polar codes by analyzing the probability density function (p.d.f) of log likelihood ratios (LLR) associated with information bits. A feedback scheme uses the RCA to predict the p.d.f of LLRs in conjunction with a repetition coding system to decrease the blocklength required for a target FER by a factor of 16. Using a rate-0.5 128-bit polar code as the initially transmitted code, the FER of the system with feedback is obtained by theoretical analysis and verified by simulation. Including the additional incremental transmissions the average blocklength for the system with feedback is 137.55 bits and the rate is 0.4653. Without feedback, a polar code with blocklength 2048 is required to achieve a comparable FER at a comparable rate. Intuitively, feedback allows the polar code to use fewer frozen bits in the initial transmission and then uses repetition codes to provide the needed reliability to resolve unreliable unfrozen bits identified by feedback.