The Transitional Behavior of Interference in Millimeter Wave Networks and Its Impact on Medium Access Control
The Transitional Behavior of Interference in Millimeter Wave Networks and Its Impact on Medium Access Control
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DOI：
10.1109/tcomm.2015.2509073
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发表时间：
2015-12
影响因子：
8.3
通讯作者：
H. S. Ghadikolaei;C. Fischione
中科院分区：
文献类型：
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作者：
H. S. Ghadikolaei;C. Fischione
毫米波（mmWave）通信系统使用大量的天线元件，这些天线元件可以通过窄波束成形潜在地克服严重的信道衰减。毫米波网络中的窄波束操作也减少了多用户干扰，引入了与干扰受限网络相反的噪声受限无线网络的概念。噪声受限或干扰受限机制严重影响介质访问控制（MAC）层吞吐量以及适当的资源分配和干扰管理策略。然而，这些制度被忽略在毫米波MAC层设计的当前方法中，对通信性能具有潜在的灾难性后果。在本文中，我们调查这些制度的碰撞概率和吞吐量。我们推导出易于处理的封闭形式的表达式的冲突概率和MAC层吞吐量的毫米波ad hoc网络，时隙ALOHA下操作。新的分析表明，毫米波网络可能会表现出从噪声限制到干扰限制的不可忽略的过渡行为，这取决于发射机的密度、障碍物的密度和大小、传输概率、工作波束宽度和传输功率。这样的过渡行为需要一个新的自适应混合资源分配过程的框架，同时包含基于竞争和无竞争阶段与按需实现的无竞争阶段。此外，由于干扰的过渡行为，应该重新审视基于竞争的阶段中的传统冲突避免过程，以最大化毫米波网络的吞吐量/延迟性能。我们的结论是，除非适当的混合方案进行调查，过渡行为的严重程度可能会显着降低毫米波网络的吞吐量/延迟性能。
Millimeter-wave (mmWave) communication systems use a large number of antenna elements that can potentially overcome severe channel attenuation by narrow beamforming. Narrow-beam operation in mmWave networks also reduces multiuser interference, introducing the concept of noise-limited wireless networks as opposed to interference-limited ones. The noise-limited or interference-limited regime heavily reflects on the medium access control (MAC) layer throughput and on proper resource allocation and interference management strategies. Yet, these regimes are ignored in current approaches to mmWave MAC layer design, with the potential disastrous consequences on the communication performance. In this paper, we investigate these regimes in terms of collision probability and throughput. We derive tractable closed-form expressions for the collision probability and MAC layer throughput of mmWave ad hoc networks, operating under slotted ALOHA. The new analysis reveals that mmWave networks may exhibit a non-negligible transitional behavior from a noise-limited regime to an interference-limited one, depending on the density of the transmitters, density and size of obstacles, transmission probability, operating beamwidth, and transmission power. Such transitional behavior necessitates a new framework of adaptive hybrid resource allocation procedure, containing both contention-based and contention-free phases with on-demand realization of the contention-free phase. Moreover, the conventional collision avoidance procedure in the contention-based phase should be revisited, due to the transitional behavior of interference, to maximize throughput/delay performance of mmWave networks. We conclude that, unless proper hybrid schemes are investigated, the severity of the transitional behavior may significantly reduce throughput/delay performance of mmWave networks.