Energy Efficiency Analysis of Subarray vs. Subband Beam Squint Mitigation in Wideband Beamforming

Abstract

The combination of extremely large-scale antenna arrays and ultra-wideband transmission enables future wireless communications systems to deliver the requested increase in data rates. Nevertheless, the employment of large-scale phased arrays with high relative bandwidths is limited by the beam-squint phenomenon. Two principal approaches for mitigating beam squint are subarray-based and subband-based architectures. While these methods exhibit similar achievable spectral efficiencies, their energy efficiency has not been thoroughly investigated. In this paper, we quantify and compare the energy efficiency of the receiver for the two architectures in a wideband beamforming scenario. The power consumption of key receiver components, including phase shifters (PSs), true-time delays (TTDs), and lownoise amplifiers (LNAs), is characterized. Our findings reveal that the subarray architecture achieves approximately 10× higher energy efficiency compared to the subband architecture, primarily due to the reduced number and resolution of phase shifters. Index Terms-Beam squint, true-time delay, wideband communication, energy efficiency