Concurrent WiFi backscatter communication using a single receiver in IoT networks

Abstract

The development of the Internet-of-Things (IoT) network has transformed our daily lives, enabling users to access various information. Power consumption in the IoT network is crucial since excessive power use can cause frequent battery replacements, raising environmental concerns. To address this, ambient backscatter communication has emerged owing to its ultra-low-power consumption and battery-free operation. In this paper, we focus on the design of WiFi backscatter communication. Current WiFi backscatter communication systems either operate in a single-tag mode, encountering challenges when multiple tags transmit concurrently, or require a double-receiver design to enable multi-tag concurrent communication, causing a significant reliance on a reliable channel between the WiFi transmitter and the WiFi receiver. To address these issues, we introduce ParaFi, a novel WiFi backscatter system that enables concurrent WiFi backscatter communication using a single receiver. ParaFi is designed with a key insight: a group of known pilot signals is inserted into each OFDM WiFi symbol, which provides us with an opportunity to decode multi-tag data using only a backscatter receiver. To further improve ParaFi’s reliability, we design a novel performance enhancement approach. We evaluate ParaFi’s performance under various scenarios, and our results demonstrate that ParaFi outperforms the state-of-the-art multi-tag WiFi backscatter communication system.