Imaging with WiFi

Executive Summary

The use of WiFi signals for sensing applications has seen significant interest in recent years, due in large part to the ubiquitous presence of WiFi signals. Using WiFi for localization of people and devices has been demonstrated in recent years. While these examples have shown that localization and tracking are possible using WiFi signals no systems have been demonstrated which can produce two-dimensional imagery using such signals. This is due in large part to the fact that WiFi signals tend to be spread-spectrum compared to radar signals, making traditional detection and localization difficult and often infeasible. However, our work has shown that the instantaneous wideband nature of WiFi can be beneficial in a sensing application if the receiver and signal processing are appropriately designed.

Description of Technology

This technology is a new method of creating microwave imagery by capturing the signals emitted by a small set of wireless WiFi transmitters. The imaging technique leverages the fact that the signals emitted by separate WiFi transmitters are sufficiently statistically independent to create a radiation pattern that is spatially incoherent, enabling the use of sampling using a small set of receiving antennas in a sparse array. In contrast to traditional microwave imaging, this method requires no mechanical or electrical beam scanning, and no coordination between transmitters and receivers. This WiFi imaging system furthermore requires far less receiver gain than passive microwave imagers, and significantly less bandwidth.

Key Benefits