Swift-Link: A Compressive Beam Alignment Algorithm for Practical mmWave Radios
Swift-Link: A Compressive Beam Alignment Algorithm for Practical mmWave Radios
复制标题
DOI：
10.1109/tsp.2018.2886168
复制
发表时间：
2018-06
影响因子：
5.4
通讯作者：
Nitin Jonathan Myers;A. Mezghani;R. Heath
中科院分区：
文献类型：
--
作者：
Nitin Jonathan Myers;A. Mezghani;R. Heath
下一代无线网络将利用毫米波（mmWave）频段丰富的可用频谱。然而，由于在更高带宽下存在严格的功率、成本和硬件限制，毫米波系统的设计颇具挑战性。为实现良好的通信信噪比（SNR），毫米波系统采用大型天线阵列。利用高定向波束进行波束成形是使用这些天线的一种方式。随着信道随时间变化，必须快速估计出能使信噪比最大化的波束，以降低训练开销。先前的研究利用毫米波信道稀疏这一特性，通过少量信道测量来执行基于压缩感知（CS）的波束对准。然而，现有的大多数基于压缩感知的算法都假定完全同步，在存在载波频率偏移（CFO）的情况下会失效。本文提出了Swift - Link，一种对载波频率偏移具有鲁棒性的快速波束对准算法。Swift - Link包含一种新颖的随机波束训练序列，可将由载波频率偏移导致的波束对准误差降至最低，还包含一种用于校正这些误差的低复杂度算法。即便在严格的硬件限制下，我们的算法与同类基于压缩感知的算法相比，所需的信道测量次数更少，且有理论保障。与波束扫描技术相比，Swift - Link在模数转换器处所需的输出动态范围较小。
Next generation wireless networks will exploit the large amount of spectrum available at millimeter wave (mmWave) frequencies. The design of mmWave systems, however, is challenging due to the strict power, cost, and hardware constraints at higher bandwidths. To achieve a good SNR for communication, mmWave systems use large antenna arrays. Beamforming with highly directional beams is one way to use the antennas. As the channel changes over time, the beams that maximize the SNR have to be estimated quickly to reduce the training overhead. Prior research has exploited the observation that mmWave channels are sparse to perform compressed sensing (CS) based beam alignment with few channel measurements. Most of the existing CS-based algorithms, however, assume perfect synchronization and fail in the presence of carrier frequency offset (CFO). This paper presents Swift-Link, a fast beam alignment algorithm that is robust against the offset. Swift-Link includes a novel randomized beam training sequence that minimizes the beam alignment errors due to CFO and a low-complexity algorithm that corrects these errors. Even with strict hardware constraints, our algorithm uses fewer channel measurements than comparable CS algorithms and has analytical guarantees. Swift-Link requires a small output dynamic range at the analog-to-digital converter compared to beam-scanning techniques.