No Feedback, No Problem: Capacity of Erasure Broadcast Channels with Single-User Delayed CSI
No Feedback, No Problem: Capacity of Erasure Broadcast Channels with Single-User Delayed CSI
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无反馈，没问题：单用户延迟 CSI 擦除广播信道的容量
DOI：
10.1109/isit.2019.8849448
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Alireza Vahid
中科院分区：
文献类型：
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作者：
Shih;I;Alireza Vahid
本文利用单用户延迟信道状态信息（CSI）刻画了两用户删除广播信道（BC）的容量区域。更准确地说，我们假设一个接收器不提供其信道状态的其他两个节点（另一个接收器和发送器），而另一个接收器揭示其状态全局单位延迟。这是在发射机处的“DN”混合CSI（CSIT）设置，其中发射机具有一个用户的延迟CSI而不具有另一个用户的延迟CSI。以前的结果开发机会网络编码方案，这个DN设置，严格扩大可实现的速率区域相比，无CSIT基线。然而，DN设置的容量区域的特征仍然是开放的。在这项工作中，我们开发了一种改进的可扩展性策略，并表明，容量区域，令人惊讶的是，匹配的擦除BC与全球延迟CSI的两个用户。这种改进的关键是在以前的结果是一个新的预编码策略的机会网络编码方案的重传阶段。它在重传阶段利用单用户延迟的CSI，使得来自“D”接收器的干扰可以在“N”接收器处对齐。除了具有两个私有消息的擦除BC之外，还提供了对具有附加公共消息的BC的扩展。
We characterize the capacity region of the two-user erasure broadcast channel (BC) with single-user delayed channel state information (CSI). More precisely, we assume one receiver does not provide its channel state to the other two nodes (the other receiver and the transmitter), while the other receiver reveals its state globally with unit delay. This is a "DN" hybrid CSI at the transmitter (CSIT) setting where the transmitter has the delayed CSI of one user but not the other. Previous results developed opportunistic network coding schemes for this DN setting, which strictly enlarge the achievable rate region compared to the no-CSIT baseline. Characterization of the capacity region for the DN setting, however, remained open. In this work, we develop an improved achievability strategy and show that the capacity region, surprisingly, matches that of the erasure BC with global delayed CSI of both users. The key to such improvement over previous results is a new precoding strategy for the retransmission phase of the opportunistic network coding scheme. It harnesses the single-user delayed CSI in the retransmission phase, so that interference from the "D" receiver can be aligned at the "N" receiver. Besides erasure BCs with two private messages, an extension to BCs with an additional common message is also provided.