Modern mmWave systems have limited scalability due to inflexibility in performing frequency multiplexing. All the frequency components in the signal are beamformed to one direction via pencil beams and cannot be streamed to other user directions. We present a new flexible mmWave system called mmFlexible that enables flexible directional frequency multiplexing, where different frequency components of the mmWave signal are beamformed in multiple arbitrary directions with the same pencil beam. Our system makes two key contributions: (1) We propose a novel mmWave front-end architecture called a delay-phased array that uses a variable delay and variable phase element to create the desired frequency-direction response. (2) We propose a novel algorithm called FSDA (Frequency-space to delay-antenna) to estimate delay and phase values for the real-time operation of the delay-phased array. Through evaluations with mmWave channel traces, we show that mmFlexible provides a 60-150% reduction in worst-case latency compared to baselines

翻译：现代毫米波系统因频率复用灵活性不足而面临可扩展性受限问题。信号中的所有频率分量均通过笔形波束汇聚于单一方向，无法向多用户方向进行流式传输。本文提出一种名为mmFlexible的新型灵活毫米波系统，可实现定向频率复用——使毫米波信号的各频率分量通过同等笔形波束在多个任意方向独立成束。本系统包含两项核心创新：（1）提出名为延迟相控阵列的新型毫米波前端架构，通过可变延迟与可变相位元件生成所需的频率方向响应；（2）提出名为FSDA（频率空间到延迟天线）的新型算法，用于实时解算延迟相控阵列的延迟与相位参数。基于毫米波信道追踪的评估表明，与基准方案相比，mmFlexible在最坏情况延迟方面可实现60-150%的降低。