Antenna Beam Pattern Modulation With Lattice-Reduction-Aided Detection

Abstract

This paper introduces a novel transmission design for antenna beam pattern modulation (ABPM) with a low-complexity decoding method. The concept of ABPM was first presented with optimal maximum-likelihood (ML) decoding. However, an ML detector may not be viable for practical systems when the constellation size or the number of antennas is large, such as in massive multiple-input–multiple-output (MIMO) systems. Linear detectors, on the other hand, have lower complexity but inferior performance. In this paper, we present the antenna pattern selection with a lattice-reduction-aided linear detector for ABPM to reduce the detection complexity with the bit error rate (BER) performance approaching that of ML while conserving low complexity. Simulation results show that even with this suboptimal detection, performance gain is achieved by the proposed scheme compared with different spatial modulation techniques using ML detection. In addition, to validate the results, an upper bound expression for the BER is provided for ABPM with ML detection.