Compressive Sensing for Millimeter Wave Antenna Array Diagnosis

Abstract

Abstract-The radiation pattern of an antenna array depends on the excitation weights and the geometry of the array. Due to wind and atmospheric conditions, outdoor millimeter wave antenna elements are subject to full or partial blockages from a plethora of particles like dirt, salt, ice, and water droplets. Handheld devices are also subject to blockages from random finger placement and/or finger prints. These blockages cause absorption and scattering to the signal incident on the array, modify the array geometry, and distort the far-field radiation pattern of the array. This paper studies the effects of blockages on the far-field radiation pattern of linear arrays and proposes several array diagnosis techniques for millimeter wave antenna arrays. The proposed techniques jointly estimate the locations of the blocked antennas and the induced attenuation and phase-shifts given knowledge of the angles of arrival/departure. Numerical results show that the proposed techniques provide satisfactory results in terms of fault detection with reduced number of measurements (diagnosis time) provided that the number of blockages is small compared to the array size.

Antenna Array Diagnosis for Millimeter-Wave MIMO Systems

“…The TPC matrix F can be designed as a random matrix, which can be realized by 2-bit phase shifters, whose elements are randomly selected from {1+i, 1−i, −1−i, −1+i} [12]. Since the number of blocked antennas is usually small, the vector q is a sparse vector.…”

“…Hence several antenna array diagnosis (AAD) techniques have been proposed in [6]- [12]. P. Zhang et al [6] proposed an atomic norm based algorithm for detecting the position of blocked antennas.…”

“…However, the above algorithms do not exploit the correlations between the blocked antennas. By contrast, upon exploiting the correlations between blocked antennas, a group-blockage diagnosis technique was proposed by Eltayeb et al [12]. However, this method cannot be used in the scenario where both the receive and transmit antennas are blocked at the same time.…”

Relay-Aided Channel Estimation for mmWave Systems with Imperfect Antenna Arrays

“…The design of the precoding and combining matrices for these systems is contingent on the mmWave channel state information, which is challenging to obtain. This is mainly due to hardware constraints, highpath loss, and antenna faults [5]- [7]. Moreover, antenna faults caused by, for example, blockages (partial or complete), synchronization errors, and/or simply antenna element failures, randomize the array geometry and result in uncertainties in the mmWave channel.…”

“…This is important as it allows the BS to broadcast independent training pilots (or beams) throughout the channel estimation process. The antenna diagnosis algorithm proposed in this work is different from [6], and [7], as diagnosis is performed at a remote receiver using far-field measurements, and not at the BS (location of faulty antenna) as done in [6], and [7]. Moreover, the proposed algorithm exploits channel training pilots for array diagnosis, and hence, does not require additional measurements to be made.…”