Chorusing Synchronization Signals for Ambient 5G Backscatter

TL;DR

This paper introduces a low-power, highly accurate synchronization method for 5G backscatter IoT communication, leveraging the mirror symmetry of the 5G PSS envelope to outperform existing techniques in resource efficiency.

Contribution

Proposes Symmetric Differential-based Sync, a novel synchronization approach exploiting PSS symmetry for energy-efficient 5G backscatter systems.

Findings

SD consumes 87x fewer D flip-flops than NR fine timing

SD achieves high accuracy with significantly lower resource use

Extensive testing confirms SD's effectiveness in backscatter hardware

Abstract

5G backscatter communication presents an emerging energy-efficient IoT connectivity solution with enhanced availability and data rate advantages over traditional wireless networks. For 5G backscatter, synchronization is crucial as it ensures high-quality transmission. Popular synchronization methods employ autocorrelation and cross-correlation for accurate timing, yet they are constrained by resources. Traditional cross-correlation-based methods for resource utilization optimization also fail in 5G backscatter due to the presence of multiple templates for 5G. A synchronization strategy that supports high accuracy and low power would be highly attractive for wireless backscatter communication. We propose Symmetric Differential (SD)-based Sync, an accurate and resource-efficient synchronization method for 5G backscatter. We have observed that the envelope of the 5G Primary Synchronization Signal (PSS) exhibits a unique mirror symmetry, which enables us to employ differential techniques for low-power PSS detection. We extensively evaluated our design using a testbed of backscatter hardware, SDR gNodeB, and User Equipment (UE). Results show that our SD consumes 3,175 D flip-flops, which is 87x lower than NR fine timing (NFT), 181x lower than symmetry-based semi-template sync (SST), and 30x lower than symmetric autocorrelation (SA)-based sync.