Intelligent Wireless Systems

TransFi realizes fine-grained signal emulation and allows commodity WiFi devices to emulate custom wireless physical layer, including but not limited to, custom PHY-layer preambles and new ways of agile spectrum usage. It could also improve the performance of cross-technology communication and many other wireless applications by up to 50x, enabling high-speed data communication on par with commodity WiFi.

A new backscatter system of precise, adaptive and lightweight power adaptation towards energy-efficient backscatter readers. It learns the entangled correlation between backscatter channel conditions, transmit RF power and goodput by designing a modular neural network to avoid redundancy and any confusion in training. Experiment results show improvement in energy efficiency at readers by 3.5× and reduces power consumption by up to 80%.

StarLego is a wireless system that can produce custom wireless signals over commodity devices without hardware modification. It is showcased by implementing a custom WiFi PHY preamble, and exhibits great promise to facilitate penetration of new wireless PHY techniques to existing wireless systems.

EasyPass exploits the excessive SNR margin in a wireless channel as a dedicated side channel for IoT traffic, and allow multiple access to the side channel by separating signals from different transmitters on the air. It allows multiple IoT devices to simultaneously transmit data over a congested wireless link without being delayed.

EmBee is designed to exploit the diversity of different wireless technologies’ spectrum utilization, so as to adaptively reserve occupied spectrum from the strong devices for weak wireless devices’ concurrent data transmissions. It is a new wireless PHY technique that enables cross-technology coexistence at zero cost or performance loss to these extremely weak wireless devices.

We present a novel design of high-throughput wireless side channel, which operates concurrently with the existing wireless network channel over the same spectrum but dedicates to real-time traffic. Our key idea of realizing such a side channel is to exploit the excessive SNR margin in the wireless network to encode data as patterned interference. We design such patterned interference in the form of energy erasure over specific subcarriers in an OFDM-based wireless network, and achieve a data rate of 1.25 Mbps in the side channel without affecting the existing wireless network links.

This work presents vMod, a lightweight and practical solution towards maximum wireless network throughput by redesigning the wireless link rates from discrete to continuous. The key idea of vMod is to modulate a fractional number of data bits into each symbol by employing the Variable-Length Code (VLC), which is able to statistically yield any link rate.