MajorizationMinimization Algorithms for Analog Beamforming with LargeScale Antenna Arrays Beamforming with largescale antenna arrays (LSAA) is one of the predominant operations in designing wireless communication systems. However, the implementation of a fully digital system significantly increases the number of required radiofrequency (RF) chains, which may be prohibitive. Thus, analog beamforming based on a phaseshifting network driven by a variable gain amplifier (VGA) is a potential alternative technology. In this paper, we cast the beamforming vector design problem as a beampattern matching problem, with an unknown power gain. This is formulated as a unitmodulus leastsquares (ULS) problem where the optimal gain of the VGA is also designed in addition to the beamforming vector. We also consider a scenario where the receivers have the additional processing capability to adjust the phases of the incoming signals to mitigate specular multipath components. We propose efficient majorizationminimization (MM) based algorithms with convergence guarantees to a stationary point for solving both variants of the proposed ULS problem. Numerical results verify the effectiveness of the proposed solution in comparison with the existing stateoftheart techniques.

Transmit beamformer design with a PAPR constraint to tradeoff between beampattern shape and power efficiency Abstract   This study examines the effect of peaktoaverage power ratio (PAPR) constraint on the transmit beamformer design problem with the goal of establishing a tradeoff between the power efficiency (maximizing the average transmitted power) and other metrics such as the power level fluctuation in mainlobe, peaksidelobe level (PSL), etc. Typically, unimodular weights are utilized in transmitbeamforming to maximize the average transmitted power. Yet, unimodular weights maximize the power efficiency at the expense of other performance metrics. It is shown that even a slight relaxation of the design problem from the unimodular condition (PAPR       1   ), say setting PAPR     xe2xa9xbd  1.1   , results in a significant improvement in other performance metrics at a negligible loss of power efficiency. To achieve the tradeoff between the metrics, an alternating direction method of multipliers (ADMM) based solution to the transmit beamformer design is given. The suggested solution is applicable to both narrowband and wideband beamformers and also to some other related problems such as the unimodular radar waveform design (code design) problem.