论文标题
缓存无线蜂窝网络的自由度
Degrees of Freedom of Cache-Aided Wireless Cellular Networks
论文作者
论文摘要
这项工作调查了一个下行链路缓存的蜂窝网络的自由度（DOF），在该网络中，基础站（BSS）的位置（BSS）被建模为网格拓扑，并且网格单元中的用户只能与附近的四个BSS通信。我们采用一种缓存放置方法，该方法具有针对网络量身定制的未经编码的预取，具有部分连接。根据BSS中的缓存内容的重叠程度，我们提出了无BS合作，部分BS合作和全BS合作的传输方案，分别针对不同的缓存大小。在特定的情况下，BS之间的常见缓存内容用于通过干扰中和取消一些不希望的信号，而干涉对准用于协调不同缓存内容的信号。我们可实现的结果表明，每个BS的每个BS的均值降低，蜂窝网络的每个用户DOF的倒数可降低分段，并且BS缓存的增益对于小型缓存区域更为重要。在给定的缓存位置方案下，我们还提供了每个用户DOF的上限，并表明当$μ\ in \ weft [\ frac {1} {2} {2} {2}，1 \ right] $以及$ \ frac {4} $ optime时，我们可实现的dof是最佳的。 $μ\ in \ left [\ frac {1} {4}，\ frac {1} {2} {2} \ right）$。
This work investigates the degrees of freedom (DoF) of a downlink cache-aided cellular network where the locations of base stations (BSs) are modeled as a grid topology and users within a grid cell can only communicate with four nearby BSs. We adopt a cache placement method with uncoded prefetching tailored for the network with partial connectivity. According to the overlapped degree of cached contents among BSs, we propose transmission schemes with no BS cooperation, partial BS cooperation, and full BS cooperation, respectively, for different cache sizes. In specific, the common cached contents among BSs are utilized to cancel some undesired signals by interference neutralization while interference alignment is used to coordinate signals of distinct cached contents. Our achievable results indicate that the reciprocal of per-user DoF of the cellular network decreases piecewise linearly with the normalized cache size $μ$ at each BS, and the gain of BS caching is more significant for the small cache region. Under the given cache placement scheme, we also provide an upper bound of per-user DoF and show that our achievable DoF is optimal when $μ\in\left[\frac{1}{2},1\right]$, and within an additive gap of $\frac{4}{39}$ to the optimum when $μ\in\left[\frac{1}{4},\frac{1}{2}\right)$.
