Interference Alignment for Line-of-Sight Channels
Interference Alignment for Line-of-Sight Channels
复制标题
视线通道的干涉对准
DOI：
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发表时间：
2008
影响因子：
2.5
通讯作者：
R. Yates
中科院分区：
文献类型：
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作者：
Leonard H. Grokop;David Tse;R. Yates
研究了带宽为W的多径环境中的全连接K用户干扰信道。我们证明了当每条链路由D条物理路径组成时，总的频谱效率可以随K线性增长。这个结果不仅在大发射功率P的限制下成立，而且对于任何固定的P也成立，因此是比自由度更强的表征。这是通过时域中的干扰对齐的形式来实现的。这个结果的一个警告是，W必须随着K增长，我们称之为带宽缩放的现象。我们的洞察力来自于检查具有单路径链路（D=1）的信道，我们将其称为视线（LOS）链路。对于这样的信道，我们建立了一个时间索引的干扰图，并将通信问题与寻找其最大独立集相关联。这个图具有平稳性，我们利用它来有效地解决问题，通过动态规划。此外，干扰图使我们能够证明带宽缩放的必要性，任何计划在LOS干扰信道上运行。带宽缩放，然后示出的K-用户干扰信道中的干扰对齐也是一个必要的成分。
The fully connected K-user interference channel is studied in a multipath environment with bandwidth W. We show that when each link consists of D physical paths, the total spectral efficiency can grow linearly with K . This result holds not merely in the limit of large transmit power P, but for any fixed P , and is, therefore, a stronger characterization than degrees of freedom. It is achieved via a form of interference alignment in the time domain. A caveat of this result is that W must grow with K, a phenomenon we refer to as bandwidth scaling. Our insight comes from examining channels with single path links (D=1), which we refer to as line-of-sight (LOS) links. For such channels, we build a time-indexed interference graph and associate the communication problem with finding its maximum independent set. This graph has a stationarity property that we exploit to solve the problem efficiently via dynamic programming. Additionally, the interference graph enables us to demonstrate the necessity of bandwidth scaling for any scheme operating over LOS interference channels. Bandwidth scaling is then shown to also be a necessary ingredient for interference alignment in the K-user interference channel.