论文标题
在分散网络误差通道上渐近实现集中率
Asymptotically Achieving Centralized Rate on the Decentralized Network MISO Channel
论文作者
论文摘要
我们分析了MXK网络MISO通道的高SNR状态,其中每个发射器都可以访问不同的通道估计值,可能具有不同的精度。最近已经显示,对于某些政权,该设置与理想的集中设置相同,并具有完美的CSI共享,其中所有发射器都具有任何发射器可用的最佳估算值。该结果受到DOF度量的局限性的限制,因为它仅提供有关SNR函数能力增长斜率的信息,而没有对给定SNR处可能的性能的任何洞察力。为了克服这一限制,我们分析了该分散的网络误差设置的速率在高SNR状态上的仿射近似,以实现其实现集中设置的DOF的天线配置。我们表明,对于一种天线配置制度,可以渐近地达到与理想集中式场景相同的可实现速率。因此,即使只有一部分发射器赋予了精确的CSI,也可以实现理想的完美CSI共享设置的波束形成增益,即可以在诸如分布式大型MIMO等场景中利用这些发射器的CSI,其中Transmit天线的数量比服务用户的数量大得多。该结果是在发射机处CSI精度与本地计算的预码器之间的一致性之间的协同妥协的结果,这是分散设置的固有权衡,在集中式CSI配置中不存在。我们提出了一个预编码方案,以实现先前的结果,该方案建立在不均匀的结构上,其中某些发射机为了使用传输参数而降低了自己的预编码的精度,而其他发射器可以更容易地预测。
We analyze the high-SNR regime of the MxK Network MISO channel in which each transmitter has access to a different channel estimate, possibly with different precision. It has been recently shown that, for some regimes, this setting attains the same Degrees-of-Freedom as the ideal centralized setting with perfect CSI sharing, in which all the transmitters are endowed with the best estimate available at any transmitter. This result is restricted by the limitations of the DoF metric, as it only provides information about the slope of growth of the capacity as a function of the SNR, without any insight about the possible performance at a given SNR. To overcome this limitation, we analyze the affine approximation of the rate on the high-SNR regime for this decentralized Network MISO setting for the antenna configurations in which it achieves the DoF of the centralized setting. We show that, for a regime of antenna configurations, it is possible to asymptotically attain the same achievable rate as in the ideal centralized scenario. Consequently, it is possible to achieve the beamforming gain of the ideal perfect-CSI-sharing setting even if only a subset of transmitters is endowed with precise CSI, which can be exploited in scenarios such as distributed massive MIMO where the number of transmit antennas is much bigger than the number of served users. This outcome is a consequence of the synergistic compromise between CSI precision at the transmitters and consistency between the locally-computed precoders, which is an inherent trade-off of decentralized settings that does not exist in a centralized CSI configuration. We propose a precoding scheme achieving the previous result, which is built on an uneven structure in which some transmitters reduce the precision of their own precoding for the sake of using transmission parameters that can be more easily predicted by the other transmitters.