WiFi/4G/5G Based Wireless Sensing: Theories, Applications and Future Directions

Wireless technologies have achieved great success in data communication. Besides the traditional communication function, in recent years, wireless technologies have been actively explored for sensing purposes. Promising progress has been achieved with a wide variety of applications supported by wireless sensing, demonstrating a great potential of integrating sensing with communication in the next generation WiFi and 6G wireless networks. In this chapter, we intend to present a big picture of the fast-growing wireless sensing field, focusing on WiFi sensing. Fundamental sensing theories including the Fresnel zone model, the Doppler-velocity model and the sensing-signal-to-noise ratio (SSNR) are introduced to unmask the underlying sensing principles and quantify the sensing capabilities. Multiple representative applications are then utilized to showcase the unique characteristics of wireless sensing. At the end, challenges associated with integrated sensing and communication (ISAC) are discussed to shed light on possible future research directions.