Load Modulated Arrays Using Channel Modulation with RF Mirrors

Abstract

Multiantenna transmission using load modulated arrays (LMAs) is gaining recent research interest. LMAs use a single central power amplifier and tune the antenna loads according to the information signal. In this paper, we propose a novel multiantenna transmitter architecture that can enable high-rate transmissions using LMAs. The proposed architecture uses channel modulation with RF mirrors in conjunction with antenna load modulation to transmit information bits. The proposed architecture has two key advantages: 1) it facilitates simple construction of high-rate signal sets suited for LMAs, and 2) it requires significantly fewer channel coefficients to be estimated at the receiver compared to conventional channel modulation architectures. The proposed architecture is shown to achieve improved bit error performance compared to conventional load modulation as well as spatial modulation, which are also single power amplifier transmission schemes. We also investigate the use of the proposed transmission scheme in a multiuser setting on the uplink. The proposed scheme not only offers the advantage of RF hardware simplicity at the user equipment but also requires fewer receive antennas at the base station to achieve a target bit error performance.