DEWS: A Distributed Measurement Scheme for Efficient Wireless Sensing

One of the key challenges for wireless sensing systems is how to efficiently enable wireless sensing capabilities for multiple devices while leveraging existing wireless communication resources. In this paper, we propose DEWS, a distributed channel measurement scheme that allows multiple transmitters to perform sensing tasks simultaneously, which considers three key issues in wireless sensing tasks: multi-device sensing resolution, multi-device sensing reliability, and multi-device sensing accuracy. First, we use a carefully designed distributed Resource Unit (dRU) allocation scheme based on OFDMA to ensure that multiple devices perform sensing tasks simultaneously with the entire bandwidth, thereby improving the sensing resolution. Then, a subcarrier linear phase shift scheme is designed to avoid signal interference between different transmitting devices and improve the reliability of multi-device sensing. This scheme realizes the fine-grained Time Division Multiplexing (TDM) of multiple devices, which can also increase the number of simultaneous access of sensing devices. Finally, a sensing accuracy improvement algorithm combining a single antenna-based motion recovery method utilizing Independent Component Analysis (ICA) and sampling frequency offset (SFO) correction is proposed, to further help DEWS to break the inherent bandwidth limits and recover different motions at similar distances. We verify the effectiveness of DEWS through extensive experimental testing using commercial USRPs.