Channel Sounding Using Multiplicative Arrays Based on Successive Interference Cancellation Principle

Ultramassive multiple-input–multiple-output (MIMO) systems have been seen as the key radio technology for the advancement of wireless communication systems, due to its capability to better utilize the spatial dimension of the propagation channels. Channel sounding is essential for developing accurate and realistic channel models for the massive MIMO systems. However, channel sounding with large-scale antenna systems has faced significant challenges in practice. The real antenna array (RAA)-based sounder suffers from high complexity and cost, while virtual antenna array (VAA) solutions are known for its long measurement time. Notably, these issues will become more pronounced as the antenna array configuration gets larger for future radio systems. In this article, we propose the concept of multiplicative array (MA) for channel sounding applications to achieve large antenna aperture size with reduced number of required antenna elements. The unique characteristics of the MA are exploited for wideband spatial channel sounding purposes, supported by both one-path and multipath numerical simulations. To address the fake paths and distortion in both angular and delay profiles inherent to MA in multipath channel sounding, a novel channel parameter estimation algorithm based on successive interference cancellation (SIC) is proposed. Both numerical simulations and experimental validation results are provided to demonstrate the effectiveness and robustness of the proposed SIC algorithm for the MA. This research offers a cost-effective alternative to conventional uniform rectangular array (URA) for channel sounding in massive MIMO systems, contributing to the ongoing exploration of practical deployment solutions for future applications.