Wireless devices like cell phones, tablets, and laptops contain radios that the devices use to connect to the Internet and other devices.  The connections are made through wireless networks, for example, cellular and Wi-Fi networks.  The radios include both transmitters and receivers.  Although radio transmitters are regulated, performance of the receivers in the radios is also an important limiting factor in the overall performance of wireless networks.  The performance of a receiver determines how close in frequency it can be to other signals while still receiving a desired signal, which carries the voice, data, or video that are needed by the user of the device that contains the receiver.  Receiver performance is primarily determined by the radio frequency (RF) front end of the receiver.  The RF front end is a sequence of analog electronic components that process received signals before they are converted to a digital form.

Some characteristics of receiver RF front ends are nonlinear, which means that a small change in the power of signals on nearby frequencies can cause a large change in the ability of a receiver to receive a desired signal.  This is important because even if some of the receivers in devices like cell phones that use a wireless network have high-performance receivers, other devices that use the network may have less well-designed and lower-performing receivers.  Devices with these lower-quality receivers will be unable to communicate when other devices use nearby frequencies in the same area, and the whole network will be less efficient.  However, the performance of the network could still be improved by understanding what devices are using it and how well their receiver RF front ends perform and by managing the use of frequencies within the network to achieve good performance in spite of variations in receiver quality among devices that use the network.

In this project, researchers developed equations that describe the performance of a receiver in a band of radio frequencies used by other signals.  The equations can be used to calculate an estimated upper bound, or speed limit, for the data rate that a receiver can achieve under a given set of conditions.  The researchers also developed approaches for efficiently using frequencies and other resources in a wireless system based on knowledge of each receiver's performance.  The researchers used the results to study receiver effects on wireless communication systems that use both 4G and 5G cellular standards, future cellular systems that will use 5G and 6G standards, and coexistence between wireless communication systems and radars that operate in a shared RF band or range of radio frequencies. 

Researchers who worked on the project shared their results through multiple peer-reviewed journal and conference papers, as well as tutorial sessions at conferences and other presentations.  In 2022, results from the project were included in response to a Notice of Inquiry by the Federal Communications Commission (FCC) to gather information so that the FCC can consider the effects of receiver performance as it makes rules for wireless systems in the future.  The research team developed over 200 slides, plus interactive web-based simulations, for teaching and learning about project results.  These learning resources will be available on the internet under open-source licenses.

Last Modified: 08/15/2023
Modified by: Carl B Dietrich