We consider a queue-channel model that captures the waiting time-dependent degradation of information bits as they wait to be transmitted. Such a scenario arises naturally in quantum communications, where quantum bits tend to decohere rapidly. Trailing the capacity results obtained recently for certain queue-channels, this paper aims to construct practical channel codes for the erasure queue-channel (EQC) -- a channel characterized by highly correlated erasures, governed by the underlying queuing dynamics. Our main contributions in this paper are twofold: (i) We propose a generic `wrapper' based on interleaving across renewal blocks of the queue to convert any capacity-achieving block code for a memoryless erasure channel to a capacity-achieving code for the EQC. Next, due to the complexity involved in implementing interleaved systems, (ii) we study the performance of LDPC and Polar codes without any interleaving. We show that standard Ar{\i}kan's Polar transform polarizes the EQC for certain restricted class of erasure probability functions. We also highlight some possible approaches and the corresponding challenges involved in proving polarization of a general EQC.

翻译：我们研究了一种队列信道模型，该模型刻画了信息比特因等待传输而产生的时延依赖性退化现象。这一场景在量子通信中自然出现——量子比特会迅速退相干。追随近期针对某些队列信道取得的容量结果，本文致力于为擦除队列信道（EQC）构建实用的信道编码方案——该信道由底层队列动态主导的强相关擦除特性所表征。本文主要贡献体现在两方面：(i) 我们提出了一种基于队列更新块间交织的通用“包装器”框架，可将任意无记忆擦除信道的容量可达分组码转化为EQC的容量可达码。其次，考虑到交织系统实现的复杂性，(ii) 我们研究了无交织条件下LDPC码与Polar码的性能表现。研究表明，对于特定受限类别的擦除概率函数，标准的Arıkan极化变换可使EQC产生极化现象。我们还指出了证明一般EQC极化现象时可行的若干方法路径及其对应的挑战。