Transmit Power Optimization for Integrated Sensing and Backscatter Communication

TL;DR

This paper proposes an integrated sensing and backscatter communication system that optimizes power and beamforming to enhance communication and sensing rates in IoT networks, demonstrating significant performance gains.

Contribution

It introduces a novel ISABC system with joint optimization of beamformers and reflection coefficients, providing closed-form solutions and demonstrating substantial rate improvements.

Findings

75% increase in sum communication and sensing rates with ten antennas.

Only 3.4% increase in transmit power for the proposed system.

Minimal power increase (0.24%) with active tags compared to conventional methods.

Abstract

Ambient Internet of Things networks use low-cost, low-power backscatter tags in various industry applications. By exploiting those tags, we introduce the integrated sensing and backscatter communication (ISABC) system, featuring multiple backscatter tags, a user (reader), and a full-duplex base station (BS) that integrates sensing and (backscatter) communications. The BS undertakes dual roles of detecting backscatter tags and communicating with the user, leveraging the same temporal and frequency resources. The tag-reflected BS signals offer data to the user and enable the BS to sense the environment simultaneously. We derive both user and tag communication rates and the sensing rate of the BS. We jointly optimize the transmit/received beamformers and tag reflection coefficients to minimize the total BS power. To solve this problem, we employ the alternating optimization technique. We offer a closed-form solution for the received beamformers while utilizing semi-definite relaxation and slack-optimization for transmit beamformers and power reflection coefficients, respectively. For example, with ten transmit/reception antennas at the BS, ISABC delivers a 75% sum communication and sensing rates gain over a traditional backscatter while requiring a 3.4% increase in transmit power. Furthermore, ISABC with active tags only requires a 0.24% increase in transmit power over conventional integrated sensing and communication.