Recent studies show that high-power cross-technology interference is becoming a major problem in today’s 802.11 networks. Devices like baby monitors and cordless phones can cause a wireless LAN to lose connectivity. The existing approach for dealing with such high-power interferers makes the 802.11 network switch to a different channel; yet the ISM band is becoming increasingly crowded with diverse technologies, and hence many 802.11 access points may not find an interference-free channel.
This project presents TIMO, a MIMO design that enables 802.11n to communicate in the presence of high-power cross-technology interference. Unlike existing MIMO designs, however, which require all concurrent transmissions to belong to the same technology, TIMO can exploit MIMO capabilities to decode in the presence of a signal from a different technology, hence enabling diverse technologies to share the same frequency band. We implement a prototype of TIMO in GNURadio-USRP2 and show that it enables 802.11n to communicate in the presence of interference from baby monitors, cordless phones, and microwave ovens, transforming scenarios with a complete loss of connectivity to operational networks.


Clearing the RF Smog: Making 802.11n Robust to Cross-Technology Interference
Shyamnath Gollakota, Fadel Adib, Dina Katabi, and Srini Seshan


Shyamnath Gollakota
Massachusetts Institute of Technology

Fadel Adib
Massachusetts Institute of Technology

Dina Katabi
Massachusetts Institute of Technology

Srini Seshan
Carnegie Mellon University

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