Delay-Sensitive Communications Over IR-HARQ: Modulation, Coding Latency, and Reliability
Delay-Sensitive Communications Over IR-HARQ: Modulation, Coding Latency, and Reliability
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DOI：
10.1109/jsac.2019.2898784
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发表时间：
2019-02
影响因子：
16.4
通讯作者：
Cenk Sahin;Lingjia Liu;E. Perrins;Liangping Ma
中科院分区：
文献类型：
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作者：
Cenk Sahin;Lingjia Liu;E. Perrins;Liangping Ma
随着延迟敏感应用（例如，实时会话视频、在线游戏和增强现实）以及未来超可靠低延迟通信（如触觉互联网）的趋势，有限码块长度约束下的无线系统性能分析变得极其重要。本文研究了有限块长度和延迟违规概率约束下（相关）Rayleigh衰落信道上增量冗余混合自动重传请求（IR-HARQ）的最大可实现吞吐量与调制方案的关系。HARQ轮的最大数量与传输块大小一起指定IR-HARQ方案的底层编码延迟。一个框架，即HARQ马尔可夫模型（HARQ-MM），被引入到跟踪的吞吐量和错误的概率的IR-HARQ在瑞利衰落信道的调制方案的函数。具有有限输入字母的并行加性白色高斯噪声信道的色散（例如，脉冲幅度调制）进行了分析表征。它是用来识别底层HARQ-MM的状态转移概率。算法开发，以有效地计算HARQ-MM的稳态分布。广泛的性能进行评估，这表明了良好的匹配之间的吞吐量性能的理论框架，其特征在于实现的实际信道编码。
With the growing popularity of delay-sensitive applications (e.g., real-time conversational video, online gaming, and augmented reality) and future trends toward ultra-reliable low-latency communications such as the tactile Internet, performance analysis of wireless systems under the finite code blocklength constraint becomes extremely important. In this paper, we investigate the maximum achievable throughput of incremental redundancy-hybrid automatic repeat request (IR-HARQ) over the (correlated) Rayleigh fading channel under finite blocklength and delay-violation probability constraints as a function of the modulation scheme. The maximum number of HARQ rounds together with the transport block size specifies the underlying coding latency of the IR-HARQ scheme. A framework, namely the HARQ Markov model (HARQ-MM), is introduced to track the throughput and the probability of error of IR-HARQ over the Rayleigh fading channel as a function of the modulation scheme. The dispersion of parallel additive white Gaussian noise channels with finite input alphabets (e.g., pulse amplitude modulation) is analytically characterized. It is used to identify the state transition probabilities of the underlying HARQ-MM. An algorithm is developed to efficiently compute the steady-state distribution of the HARQ-MM. Extensive performance evaluation is conducted, which shows a good match between the throughput performance characterized by the theoretical framework and that achieved by the practical channel codes.