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

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 multi-user uplink MU-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 Visible Light Communication Systems. Designed and implemented a vehicular VLC system with applications to Internet access and vehicle-to-vehicle communication and safety and developed a joint light-radio WLAN architecture (ACM VANET 2011 and IEEE SECON 2017)
ongoing Wireless Security. Evaluated DoS and security threats to wireless networks and demonstrated fundamental limits of using CSI as a shared secret. (IEEE INFOCOM 2012 and ACM MobiHoc 2017)
ongoing 60 GHz and Millimeter Wave Access. Designed and implemented prototypes for efficient steering and adaptation of highly directional high frequency WLANs (IEEE INFOCOM 2015 and ACM MobiHoc 2016)

 

Past Projects

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 with custom hardware and software for 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)