Single-user CSIT can be quite useful for state-dependent broadcast channels
Single-user CSIT can be quite useful for state-dependent broadcast channels
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单用户 CSIT 对于状态相关的广播频道非常有用
DOI：
10.1109/isit.2016.7541281
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
I
中科院分区：
文献类型：
--
作者：
Shih;I
研究了在发射端具有异构信道状态信息的状态相关广播信道。CSIT的异质性在于控制从发射机到不同接收机的链路的信道状态的及时性-每个链路的CSI可以是完美的（因果地或非因果地）、延迟的或在发射机处不可用。我们专注于擦除BC和突发高斯BC，其中信道状态由无记忆伯努利过程控制，独立于用户。对于具有完美单用户CSIT的擦除BC，我们描述了其容量区域，而不管其他用户的CSIT，并表明该容量区域严格包含没有CSIT的容量区域。对于延迟的单用户CSIT的情况下，我们提出了一个机会网络编码方案，实现了严格更大的速率区域比无CSIT容量区域。这些结果被扩展到突发高斯BC，其中对于完美的单用户CSIT场景，容量区域的特征在于在有界间隙内;并且对于延迟的单用户CSIT场景，导出基于机会网络编码方案的速率区域。作为推论，单用户CSIT能够增加突发高斯BC的总自由度（DoF）。我们的结果与Davoodi和Jafar [1]最近的负面结果形成鲜明对比，其中表明对于快衰落MISO广播信道，单用户CSIT在总和DoF方面根本没有帮助。
State-dependent broadcast channels (BC) with heterogeneous channel state information available at the transmitter (CSIT) are studied. The heterogeneity of CSIT lies in the timeliness of channel state that governs the link from the transmitter to different receivers - CSI of each link can be perfectly (causally or non-causally), delayed, or not available at the transmitter. We focus on the erasure BC and the bursty Gaussian BC, where the channel states are governed by memoryless Bernoulli processes, independent across users. For the erasure BC with perfect single-user CSIT, we characterize its capacity region regardless of the CSIT of the other user and show that this capacity region strictly contains that with no CSIT. For the case with delayed single-user CSIT, we propose an opportunistic network coding scheme that achieves a strictly larger rate region than the no-CSIT capacity region. These results are extended to the bursty Gaussian BC, where for the perfect single-user CSIT scenario, the capacity region is characterized to within a bounded gap; and for the delayed single-user CSIT scenario, a rate region based the opportunistic network coding scheme is derived. As a corollary, single-user CSIT is able to increase the sum degrees of freedom (DoF) for bursty Gaussian BC. Our result is in sharp contrast to the recent negative result by Davoodi and Jafar [1], where it is shown that for fast-fading MISO broadcast channel, single-user CSIT does not help at all in terms of sum DoF.