Analysis of Massive MIMO-Enabled Downlink Wireless Backhauling for Full-Duplex Small Cells
Analysis of Massive MIMO-Enabled Downlink Wireless Backhauling for Full-Duplex Small Cells
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DOI：
10.1109/tcomm.2016.2555908
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发表时间：
2015-11
影响因子：
8.3
通讯作者：
H. Tabassum;A. Sakr;E. Hossain
中科院分区：
文献类型：
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作者：
H. Tabassum;A. Sakr;E. Hossain
低功率无线设备在自干扰(SI)消除能力方面的最新进展推动了小蜂窝网络(SCN)中的带内全双工(FD)无线回程。带内FD无线回程同时允许对小型小区的回程和接入链路使用相同的频谱。本文利用随机几何中的工具，建立了一个框架来模拟用户在具有大规模多输入多输出(MIMO)支持的无线回程的给定SCN中的下行链路速率覆盖概率。所考虑的SCN由以带内或带外回程模式以一定概率配置的小小区的混合组成。在所考虑的分层网络中，用户的性能受到几个干扰源的限制，例如回程干扰、小蜂窝基站(SBS)到SBS的干扰以及SI。此外，由于大规模MIMO中的信道硬化效应，回程链路只经历长期的信道效应，而接入链路同时经历长期和短期的信道效应。因此，所开发的框架可以灵活地表征不同的干扰源，同时捕获接入和回程信道的异质性。在特定场景中，该框架能够推导出闭合形式的覆盖概率表达式。在完全回程覆盖的情况下，利用简化的表达式以封闭的形式优化带内和带外小小区在SCN中的比例。最后，提出了一些补救方案，这些方案可以潜在地缓解回程干扰，从而提高带内FD无线回程的性能。数值结果研究了带内无线回程有用的场景，并证明了在无线回程SCN中保持带内和带外FD小小区的正确比例是至关重要的。
Recent advancements in self-interference (SI) cancellation capability of low-power wireless devices motivate in-band full-duplex (FD) wireless backhauling in small cell networks (SCNs). In-band FD wireless backhauling concurrently allows the use of the same frequency spectrum for the backhaul as well as access links of the small cells. In this paper, using tools from stochastic geometry, we develop a framework to model the downlink rate coverage probability of a user in a given SCN with massive multiple-input-multiple-output (MIMO)-enabled wireless backhauls. The considered SCN is composed of a mixture of small cells that are configured in either in-band or out-of-band backhaul modes with a certain probability. The performance of the user in the considered hierarchical network is limited by several sources of interference, such as the backhaul interference, small cell base station (SBS)-to-SBS interference, and the SI. Moreover, due to the channel hardening effect in massive MIMO, the backhaul links only experience long term channel effects, whereas the access links experience both the long term and the short term channel effects. Consequently, the developed framework is flexible to characterize different sources of interference while capturing the heterogeneity of the access and backhaul channels. In specific scenarios, the framework enables deriving closed-form coverage probability expressions. Under perfect backhaul coverage, the simplified expressions are utilized to optimize the proportion of in-band and out-of-band small cells in the SCN in the closed form. Finally, a few remedial solutions are proposed that can potentially mitigate the backhaul interference and in turn improve the performance of in-band FD wireless backhauling. Numerical results investigate the scenarios in which in-band wireless backhauling is useful and demonstrate that maintaining a correct proportion of in-band and out-of-band FD small cells is crucial in wireless backhauled SCNs.