Sight distance propagation path judging method and system on basis of time domain features of WiFi (Wireless Fidelity) physical layer

Abstract

The invention provides a sight distance propagation path judging method on the basis of time domain features of a WiFi (Wireless Fidelity) physical layer, which comprises the following steps of: extracting an envelope of a main path of a receiving signal from an indoor WiFi wireless local area network physical layer; calculating a skewness value of the envelope; and according to the skewness value, judging whether a main propagation path between a receiver and a transmitter is a sight distance propagation path. According to the invention, by extracting multipath propagation time domain information from the physical layer, channel impulse response is utilized to filter out noise and influence of a non-sight-distance propagation path delayed for long time, movement of the receiver is utilized to improve randomness of the non-sight-distance propagation path and simultaneously main determinacy of the sight distance propagation path, accuracy and robustness of judging the sight distance propagation path are improved, and judgment on the sight distance path propagation is implemented on universal wireless local area network equipment and in a typical indoor environment.

Description

technical field [0001] The invention relates to the field of mobile and pervasive computing, in particular to a method and system for extracting time-domain features from physical layer information of a WiFi wireless local area network and judging a line-of-sight propagation path. Background technique [0002] The popularization and application of wireless network equipment has promoted the triple convergence of ubiquitous computing, mobile computing and human-oriented computing. As a wireless local area network that is widely deployed indoors, WiFi is no longer just a carrier of information. Rapidly innovative applications continue to expand the application scenarios of WiFi to pervasive computing and human-computer interaction such as indoor positioning, through-wall scanning, and gesture recognition. and other fields. To make these emerging applications applicable to indoor scenarios where multipath propagation is rich, it is necessary to combat the typical non-line-of-s...

AI Technical Summary

Problems solved by technology

However, the existing WiFi protocol has a bandwidth of only 20MHz and cannot distinguish propagation paths with a path difference of less than 15m. However, it is usually used in indoor services and application scenarios that require meter-level accuracy.

This mismatch between the bandwidth (time resolution) and the physical space scale makes the existing line-of-sight and non-line-of-sight propagation path discrimination methods not directly applicable to the network that can only obtain coarse-grained channel measurement information and work in short-distance indoor propagation environments. WiFi network

Although the recent work uses the multi-antenna (MIMO) technology to extend the discrimination method of line-of-sight and non-line-of-sight propagation paths to airspace, it still needs to modify the hardware, so it is not suitable for large-scale promotion and application

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