Directional Frame Timing Synchronization in Wideband Millimeter-Wave Systems With Low-Resolution ADCs
Directional Frame Timing Synchronization in Wideband Millimeter-Wave Systems With Low-Resolution ADCs
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DOI：
10.1109/twc.2019.2935733
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发表时间：
2018-09
影响因子：
10.4
通讯作者：
Dalin Zhu;R. Bendlin;S. Akoum;Arunabha Ghosh;R. Heath
中科院分区：
文献类型：
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作者：
Dalin Zhu;R. Bendlin;S. Akoum;Arunabha Ghosh;R. Heath
在本文中，我们提出并评估了一种新的波束成形策略，用于宽带毫米波（mmWave）系统中的定向帧定时同步，该系统采用低分辨率模数转换器（ADC）。在所采用的系统模型中，我们假设在基站处配备的多个射频链在模拟域中同时形成多个同步波束。我们制定相应的定向帧定时同步问题作为一个最大最小多播波束形成问题下的低分辨率量化。我们首先表明，制定的问题不能有效地解决传统的基于单流波束成形的方法，由于大的量化损失和有限的波束码本分辨率。然后，我们开发了一种新的多波束探测为基础的定向同步策略，目标是最大限度地提高所有用户之间的最小接收同步信号量化加噪声比（SQNR）。利用一个共同的同步信号结构设计，所提出的方法合成一个有效的复合波束从同时探测波束，以更好地权衡波束形成增益和量化失真。数值结果表明，对于宽带毫米波系统与低分辨率ADC，我们提出的方法的定时同步性能优于现有的方法，由于在接收同步SQNR的改善。
In this paper, we propose and evaluate a novel beamforming strategy for directional frame timing synchronization in wideband millimeter-wave (mmWave) systems operating with low-resolution analog-to-digital converters (ADCs). In the employed system model, we assume multiple radio frequency chains equipped at the base station to simultaneously form multiple synchronization beams in the analog domain. We formulate the corresponding directional frame timing synchronization problem as a max-min multicast beamforming problem under low-resolution quantization. We first show that the formulated problem cannot be effectively solved by conventional single-stream beamforming based approaches due to large quantization loss and limited beam codebook resolution. We then develop a new multi-beam probing based directional synchronization strategy, targeting at maximizing the minimum received synchronization signal-to-quantization-plus-noise ratio (SQNR) among all users. Leveraging a common synchronization signal structure design, the proposed approach synthesizes an effective composite beam from the simultaneously probed beams to better trade off the beamforming gain and the quantization distortion. Numerical results reveal that for wideband mmWave systems with low-resolution ADCs, the timing synchronization performance of our proposed method outperforms the existing approaches due to the improvement in the received synchronization SQNR.