Edward Knightly, Sheafor-Lindsay Professor in Electrical and Computer Engineering and a professor in the Department of Computer Science, and Ashutosh Sabharwal, Ernest Dell Butcher Professor of Engineering, Electrical and Computer Engineering and a professor in the Department of Computer Science at the George R. Brown School of Engineering and Computing, recently won the 2025 ACM SIGMOBILE Test-of-Time paper award for their 2002 paper published in ACM MobiCom. They will receive this award at the MobiCom conference in Hong Kong this November.
Other authors of this award-winning paper titled — “Opportunistic Media Access for Multirate Ad Hoc Network — were Knightly’s then-doctoral students, Bahar Sadeghi and Vikram Kanodia.
ACM SIGMOBILE is the international professional organization for scientists, engineers, executives, educators, and students dedicated to mobile computing and wireless communications. This award recognizes papers that have had a sustained and significant impact in the mobile signaling community over at least a decade.
This widely cited paper has left a lasting impact on the modern wireless and mobile computing industry—the approach they developed is now deployed in all commercial WiFi products and the revolutionary ideas they proposed have now been adopted as the industry standard.
In their paper, the researchers introduced a novel protocol called Opportunistic Auto Rate (OAR) using which wireless transmitters with high-quality channels could send multiple packets per access. This concept represented a significant improvement over the wireless transmission technologies available at the time.
“Traditional wireless transmission protocols adjusted the rate of data transfer based on factors like signal-to-noise ratio (SNR) or packet loss rates and often reacted to channel fluctuations on a packet-by-packet basis, which did not fully capitalize available high-quality channels for sustained periods,” Sabharwal said. “In contrast, our approach dynamically adapted the data transmission rate based on availability and conditions of real-time high-quality channels in wireless networks, particularly those used for mobile devices in vehicles and other ad hoc networks.”
Their core idea was to opportunistically leverage favorable channel conditions to transmit data at higher rates and for extended durations. Adoption of this concept by industry accelerated transmission rates and improved data transfer efficiency, which proved to be particularly important as the wireless communications industry experienced an exponential surge in traffic over the past decade.
“This paper also pioneered the concept of transmission time opportunities in wireless networks and mobile computing, which means that each user or application receives an equal maximum share of the available time for accessing the network or utilizing resources,” Knightly said. “This ensures both high network efficiency and equitable resource allocation and prevents dominant users or applications from monopolizing the system, resulting in a better experience for all. The concepts and methods from that paper were the foundation for how wireless and mobile computing networks are now configured and function.”
This research was supported by the National Science Foundation’s Information Technology Research Program, a forward-looking program which recognized and supported the fundamental research advances that make Wi-Fi what it is today.
This is Prof. Sabharwal’s third ACM SIGMOBILE Test-of-Time award. His previous awards were for full-duplex wireless, which demonstrated the feasibility of wireless radios to transmit and receive signals simultaneously, potentially doubling network capacity, and the groundbreaking Wireless Open-Access Research Platform (WARP) project, a customized platform for open-access research in advanced wireless algorithms and applications.