The extremely high frequency of Millimeter-Wave technology warrants Gbps throughput for the next-generation wireless communication systems, but mmWave signals also suffer from severe path loss due to high attenuation. To compensate for this loss, mmWave radios establish communication links via directional beams so as to increase channel gains and communication range. Until recently, the measurement studies on mmWave technology were mainly based on prototypes built from band-limited Software Defined Radio, which could not characterize performance in realistic settings. Latest studies using commodity hardware reports straightforward measurements on the impact of environment settings but did not present deep analysis on the correlations of low-layer information. Meanwhile, those studies lack the ability to configure commodity devices under controlled settings, for instance, a single beam pattern for experimentation, thus failing to perform deeper analysis on low-layer protocol parameters. In this paper, we conduct extensive measurements in typical indoor settings, utilizing 802.11ad-compliant commodity hardware. Different from earlier studies, we hack the firmware and gain the privilege to modify physical layer settings online, enabling us to gain more insights under controlled settings. Essentially, we have demonstrated that (1) Signal-to-Noise Ratio, the criteria for beam control, may not be positively correlated with throughput, (2) sticking to a single beam pattern during data transmission can lead to both channel gains and throughput improvement, and (3) only independent cross-links could interfere with each other while multi-links coordinated by one AP experience no interference. These insights lead us to rethink the existing beam control policy.

毫米波技术的极高频率保证了下一代无线通信系统的Gbps吞吐量，但是毫米波信号也因高衰减而遭受严重的路径损耗。为了补偿这种损失，mmWave无线电通过定向波束建立通信链路，以增加信道增益和通信范围。直到最近，有关毫米波技术的测量研究仍主要基于由带限软件无线电定义的原型，这些原型无法表征现实环境中的性能。使用商品硬件的最新研究报告了对环境设置影响的直接测量，但没有对底层信息的相关性进行深入分析。与此同时，这些研究缺乏在受控设置下配置商品设备的能力，例如，用于实验的单光束模式，因此无法对低层协议参数进行更深入的分析。在本文中，我们利用802.11ad兼容的商用硬件在典型的室内环境中进行了广泛的测量。与早期研究不同，我们可以破解固件并获得在线修改物理层设置的特权，从而使我们能够在受控设置下获得更多见解。从本质上讲，我们证明了（1）信噪比，即波束控制的标准，可能与吞吐量没有正相关；（2）在数据传输过程中坚持单个波束模式会导致信道增益和吞吐量改善，（3）只有独立的交叉链路会相互干扰，而由一个AP协调的多链路则不会受到干扰。这些见解使我们重新考虑了现有的光束控制策略。