Research highlights with exemplary papers (see publications and press coverage for more information):
Ongoing Projects

ongoing ASTRO: Autonomous and Tetherless Networked Drone Missions. Designed and implemented a system for data-driven drone sensing missions with on-board machine learning and SDRs (ACM DroNet 2018).
ongoing Uplink Multi-User WLAN. Discovered severe degradation of TCP downlink throughput when a MU-MIMO downlink is not paired with a MU-MIMO uplink (IEEE INFOCOM 2017) and designed a scalable uplink multi-user MIMO WLAN (NSDI 2016).
ongoing New Spectrum and New Access Techniques. Demonstrated UHF-band MU-MIMO (ACM MobiCom 2014) and an opportunistic Wi-Fi channel sounding technique (ITC 2016).
ongoing Wireless Security. Evaluated DoS and security threats to wireless networks and discovered fundamental limits of using CSI as a shared secret (IEEE INFOCOM 2012 and ACM MobiHoc 2017).
ongoing Millimeter Wave WLANs. Designed and implemented the first mmWave out-of-band beam steering (IEEE INFOCOM 2015), beam-width adaptation (ACM MobiHoc 2016), and multi-stream MIMO (ACM MobiCom 2018).


Past Projects

2010-2017 Visible Light Communication Systems. Designed and implemented a vehicular VLC system with applications to Internet access, vehicle-to-vehicle communication, and safety (ACM VANET 2011) and developed a joint light-radio WLAN architecture (IEEE SECON 2017).
2009 – 2011 Multi-User MIMO WLAN. Implemented the first multi-user MIMO WLAN and demonstrated simultaneous transmission to users separated by centimeter-scale distances (ACM MobiCom 2010).
2006 – 2013 Diverse Spectrum Access. Developed underlying theory and algorithms (IEEE/ACM Transactions on Networking 2007) and a prototype spanning 500 MHz to 5 GHz (IEEE INFOCOM 2013).
2007 – 2008 Vehicular Wi-Fi. Demonstrated vehicular Wi-Fi handoffs in 200 meter radius urban Wi-Fi cells (ACM MobiSys 2008).
2005 – 2008 Wi-Fi Modeling. Developed the first model of CSMA-based contention that characterizes starvation arising from topological and channel asymmetries (IEEE INFOCOM 2006).
2004 – 2008 Mesh Fairness and 802.11s. Designed and implemented mechanisms, algorithms, and theoretical framework for fair bandwidth distribution over multi-hop wireless networks (ACM MobiCom 2004).
2003 – 2008 Wireless for Under-served and Under-resourced Communities. Designed and deployed urban-scale wireless networks to serve previously unreached populations (Journal of Urban Technology and Technology For All Wireless).
2003 – 2008 Multi-Tier Mesh Access Networks. Architected, designed and implemented the Technology For All wireless network, the first mesh network with all Wi-Fi access, backhaul, and capacity tiers (ACM MobiSys 2006).
2003 – 2006 Clean Slate Design of Wireless Protocols. Designed and implemented a software-defined-radio (SDR) FPGA based platform for clean-slate design of wireless protocols and algorithms (HotNets 2003 and MC2R).
2002 – 2005 Opportunistic Multi-Rate Wi-Fi. Designed and evaluated opportunistic rate adaptation that scales the amount of data transmitted to the channel rate, using frame aggregation to equalize time shares for time-share fairness (ACM MobiCom 2002). This project yielded the first WLAN implementation of per-packet channel-based rate adaptation.
2002 – 2005 Internet Denial of Service. Demonstrated underlying vulnerabilities of TCP to low-rate attacks (ACM SIGCOMM 2003) and peer-to-peer networks to pollution attacks (ACM SIGMETRICS 2005).
2001 – 2005 Cloud Resource Management. Designed and implemented content distribution and access management system for distributed and multi-site Internet Data Centers (IWQoS 2002).
1994 – 2000 Quality of Service in Packet Switched Networks. Developed foundations for deterministic performance guarantees for real-time traffic (ACM SIGMETRICS ’95) and scalable techniques for Internet quality-of-service management (SIGCOMM 2000).