Fair Initial Access Design for mmWave Wireless
Fair Initial Access Design for mmWave Wireless
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DOI：
10.1109/icnp49622.2020.9259392
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
S. Srinivasan;Xi Yu;A. Keshavarz-Haddad;Ehsan Aryafar
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文献类型：
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作者：
S. Srinivasan;Xi Yu;A. Keshavarz-Haddad;Ehsan Aryafar
毫米波（mmWave）系统使用具有窄波束宽度的高度定向波束来克服与其频带相关联的高路径损耗。窄波束的使用使链路建立过程复杂化，因为发射器和接收器需要在它们可以彼此通信之前搜索适当的波束。现有的毫米波标准将波束搜索过程作为初始接入（IA）的一部分，并使用基于竞争的方案，让多个客户端在相同的搜索间隔中训练它们的波束。然而，在竞争客户端的波束之间存在严重的功率不平衡，因为客户端自然具有不同的取向并且处于距相同接入点的不同距离处。这种波束功率不平衡加上较差的竞争协议导致具有多个客户端的动态系统中较差的IA公平性。我们提出了一个联合功率控制和竞争自适应协议（创造JPOC），解决这个不公平的问题。JPOC使用开环和客户端侧功率控制机制，其减少竞争客户端之间的波束功率不平衡。它还使用了一个模型驱动的竞争适应协议，根据系统动态优化调整的竞争时间的持续时间。通过实验和仿真的综合评估表明，与现有的802.11 ad/ay标准相比，JPOC大大减少了竞争开销，提高了IA的公平性。
Millimeter-wave (mmWave) systems use highly directional beams with narrow beamwidths to overcome the high path loss associated with their frequency bands. The use of narrow beams complicates the link establishment process as the transmitter and receiver need to search for appropriate beams before they can communicate with each other. Existing mmWave standards address the beam search process as part of the initial access (IA), and use contention based schemes that let multiple clients train their beams in the same search interval. However, there exists a severe power imbalance among competing clients’ beams, as clients naturally have different orientations and are at different distances from the same access point. This beam power imbalance coupled with poor contention protocols results in poor IA fairness in dynamic systems with multiple clients. We propose a joint power control and contention adaptation protocol (coined JPOC) that addresses this unfairness problem. JPOC uses an open-loop and client-side power control mechanism that reduces the beam power imbalance among competing clients. It also uses a model-driven contention adaptation protocol that optimally adjusts the duration of the contention time according to the system dynamics. Comprehensive evaluation through a mixture of experiments and simulations show that compared to existing 802.11 ad/ay standards, JPOC substantially reduces the contention overhead and increases the IA fairness.