Timely Transmissions Using Optimized Variable Length Coding
Timely Transmissions Using Optimized Variable Length Coding
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DOI：
10.1109/infocomwkshps51825.2021.9484506
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
A. Arafa;R. Wesel
中科院分区：
文献类型：
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作者：
A. Arafa;R. Wesel
考虑一种状态更新系统，其中使用可变长码通过噪声信道向接收器发送消息。其目标是优化码字长度，以便成功解码的消息是及时的。也就是说，使得接收器处的信息年龄(AOI)最小化。采用混合ARQ(HARQ)方案，其中可变长度递增冗余(IR)比特被添加到原始传输的码字中，直到译码成功。对于每次解码尝试，都会产生非零的处理延迟。利用顺序差分优化(SDO)框架解析地导出最佳码字长度。该框架是通用的，因为它只需要作为码字长度的函数的正反馈(ACK)概率的解析表达式的知识。
A status updating system is considered in which a variable length code is used to transmit messages to a receiver over a noisy channel. The goal is to optimize the codewords lengths such that successfully-decoded messages are timely. That is, such that the age-of-information (AoI) at the receiver is minimized. A hybrid ARQ (HARQ) scheme is employed, in which variable-length incremental redundancy (IR) bits are added to the originally-transmitted codeword until decoding is successful. With each decoding attempt, a non-zero processing delay is incurred. The optimal codewords lengths are analytically derived utilizing a sequential differential optimization (SDO) framework. The framework is general in that it only requires knowledge of an analytical expression of the positive feedback (ACK) probability as a function of the codeword length.