52 – Swift-Link : Rapid and robust mmWave link configuration with provable guarantees
Beam alignment in millimeter wave (mmWave) radios is a challenging problem due to the use of large antenna arrays and poor signal-to-noise ratio before beamforming. Although compressed sensing (CS)-based algorithms offer a great promise for fast mmWave beam alignment, they fail to perform well due to hardware impairments like carrier frequency offset. Recent CS techniques that address this problem either have high complexity or do not fully exploit the structure in the problem.
In this work, we propose Swift-Link, a fast mmWave link configuration algorithm that is robust to carrier frequency offset (CFO). We propose a novel concept of trajectory by using Zadoff-Chu (ZC) sequences in the spatial domain. Such sequences have been extensively used in wireless systems along the time and frequency dimensions, but not in space. Using the concept of trajectory, we characterize the impact of CFO on sparse recovery and define the notion of robust beam alignment. Furthermore, we design a subsampling trajectory that achieves robustness to CFO. Swift-Link does not add any dimension to the standard CS problem and is computationally efficient over comparable algorithms.