Trident: Interference Avoidance in Multi-reader Backscatter Network via Frequency-space Division

2024-05-20

IEEE Conference on Computer Communications

AI Summary

In multi-reader backscatter IoT systems, inter-reader interference arises from cross-regional backscatter signals, and conventional TDMA/CSMA protocols suffer from throughput limitations due to time-division multiplexing. Method: This paper proposes a novel frequency–spatial joint interference mitigation paradigm. It introduces an adaptive tag architecture integrating tunable bandpass filtering with multi-port load switching, coupled with a channel-aware dynamic frequency and power adaptation mechanism. Contribution/Results: The approach achieves the first physical-layer spatial isolation of frequency resources, enabling conflict-free concurrent communication while significantly improving spectral efficiency. Experimental evaluation demonstrates a 3.18× throughput gain over TDMA baselines, supports full-time concurrent operation across multiple readers, and provides a scalable interference suppression solution for high-density passive IoT deployments.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Application Domains: Internet of Things, Sensor Networks & Smart Cities
• Multiagent Systems: Agent Communication

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

Backscatter is an enabling technology for battery-free sensing in industrial IoT applications. For the purpose of full coverage of numerous tags in the deployment area, one often needs to deploy multiple readers, each of which is to communicate with tags within its communication range. But the actual backscattered signals from a tag are likely to reach a reader outside its communication range, causing undesired interference. Conventional approaches for interference avoidance, either TDMA or CSMA based, separate the readers’ media accesses in the time dimension and suffer from limited network throughput. In this paper, we propose Trident, a novel backscatter tag design that enables interference avoidance with frequency-space division. By incorporating a tunable bandpass filter and multiple terminal loads, a Trident tag is able to detect its channel condition and adaptively adjust the frequency band and the power of its backscattered signals, so that all the readers in the network can operate concurrently without being interfered. We implement Trident and evaluate its performance under various settings. The results demonstrate that Trident enhances the network throughput by 3.18×, compared to the TDMA based scheme.

Problem

• Avoid interference in multi-reader backscatter networks
• Enhance network throughput via frequency-space division
• Enable concurrent reader operation without interference

Innovation

• Frequency-space division for interference avoidance
• Tunable bandpass filter and multiple terminal loads
• Frequency assignment algorithm for concurrent operation