Ultra-low-power Monostatic Backscatter Platform with Phase-Aware Channel Estimation and System-Level Validation

TL;DR

This paper introduces a low-power monostatic backscatter system with advanced channel estimation and validation, enabling efficient multimedia data transmission for IoT applications.

Contribution

It proposes a novel phase-aware channel estimation method and a complete hardware-software pipeline for a single-antenna backscatter system, validated through real-world experiments.

Findings

Achieved 500 kbps data rate at 1 meter with 158 μW power consumption.

Demonstrated successful image reconstruction over-the-air.

Achieved low EVMs of 2.97% (OOK) and 4.02% (BPSK).

Abstract

This paper presents a novel channel-estimation (CE) method that mitigates residual phase drifts in backscatter links and a full hardware and signal-processing pipeline for a single-antenna monostatic system. The platform comprises a semi-passive tag, a software-defined radio (SDR) reader, and a 2x1 planar Yagi-Uda array (7 dBi with higher than 30 dB isolation) operating at 2.4 ~ 2.5 GHz. The developed backscatter fading model accounts for round-trip propagation and temporal correlation, and employs an analytically derived resource-optimal pilot allocation strategy. At the receiver, optimized least square (LS) and linear minimum mean square error (LMMSE) CE with pilot-aided carrier frequency offset (CFO) compensation feed a zero-forcing (ZF) equalizer to suppress ISI. The prototype delivers 500 kbps at 1 m with power of 158 uW (SDR baseband) and 10 uW (RF switch), yielding 320 pJ/bit. OOK and BPSK modulations achieve measured EVMs of 2.97 % and 4.02 %, respectively. Performance is validated by BER measurements and successful reconstruction of a full-color image in an over-the-air experiment. The results demonstrate an ultra-low-power, multimedia-capable backscatter IoT link and provide practical hardware-software co-design guidance for scalable deployments.