Spatial Modulation for Ambient Backscatter Communications: Modeling and Analysis

TL;DR

This paper introduces a novel spatial modulation scheme for ambient backscatter communications with multiple antennas, providing a practical design that enhances throughput and reduces power consumption, supported by analytical and simulation results.

Contribution

It presents the first analytical model for spatial modulation in AmBC with multiple antennas, addressing design challenges and proposing an optimal detection algorithm.

Findings

Significant throughput improvement over traditional systems.

The proposed design reduces inter-antenna synchronization issues.

Simulation results validate the analytical bounds and performance gains.

Abstract

Multiple-antenna backscatter is emerging as a promising approach to offer high communication performance for the data-intensive applications of ambient backscatter communications (AmBC). Although much has been understood about multiple-antenna backscatter in conventional backscatter communications (CoBC), existing analytical models cannot be directly applied to AmBC due to the structural differences in RF source and tag circuit designs. This paper takes the first step to fill the gap, by exploring the use of spatial modulation (SM) in AmBC whenever tags are equipped with multiple antennas. Specifically, we present a practical multiple-antenna backscatter design for AmBC that exempts tags from the inter-antenna synchronization and mutual coupling problems while ensuring high spectral efficiency and ultra-low power consumption. We obtain an optimal detector for the joint detection of both backscatter signal and source signal based on the maximum likelihood principle. We also design a two-step algorithm to derive bounds on the bit error rate (BER) of both signals. Simulation results validate the analysis and show that the proposed scheme can significantly improve the throughput compared with traditional systems.