We address the worst-user bottleneck of wireless coded caching, which is known to severely diminish cache-aided multicasting gains due to the fundamental worst-channel limitation of multicasting transmission. We consider the quasi-static Rayleigh fading Broadcast Channel, for which we first show that the effective coded caching gain of the XOR-based standard coded-caching scheme completely vanishes in the low-SNR regime. Then, we reveal that this collapse is not intrinsic to coded caching. We do so by presenting a novel scheme that can fully recover the coded caching gains by capitalizing on one aspect that has to date remained unexploited: the shared side information brought about by the effectively unavoidable file-size constraint. As a consequence, the worst-user effect is dramatically ameliorated, as it is substituted by a much more subtle worst-group-of-users effect, where the suggested grouping is fixed, and it is decided before the channel or the demands are known. In some cases, the theoretical gains are completely recovered, and this is done without any user selection technique. We analyze the achievable rate performance of the proposed scheme and derive insightful performance approximations which prove to be very precise.

中文翻译：

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无线编码缓存可以通过利用有限的文件大小来克服最糟糕的用户瓶颈

我们解决了无线编码缓存的最坏用户瓶颈，由于多播传输的基本最差信道限制，众所周知，这将严重降低缓存辅助的多播增益。我们考虑准静态瑞利衰落广播信道，对此我们首先表明，基于异或运算的标准编码缓存方案的有效编码缓存增益在低SNR体制中完全消失了。然后，我们揭示这种崩溃不是编码缓存所固有的。为此，我们提出了一种新颖的方案，该方案可以利用迄今尚未利用的一个方面来充分恢复编码缓存的收益：有效避免的文件大小约束带来的共享边信息。结果，极大地减轻了最坏用户的影响，因为它被更微妙的用户最坏群体效应所替代，在这种情况下，建议的分组是固定的，并且是在了解渠道或需求之前确定的。在某些情况下，理论上的收益可以完全恢复，而无需任何用户选择技术即可完成。我们分析了所提出方案的可实现的速率性能，并得出了具有洞察力的性能近似值，该近似值被证明是非常精确的。