ECE Team Wins Best Paper at SECON 2014
Edward Knightly, professor and chair of electrical and computer
engineering, PhD student Oscar Bejarano, and collaborators Eugenio Magistretti,
recent Rice PhD graduate, and Omer Gurewitz, former Rice postdoctoral student
and professor at Ben Gurion University, won Best Paper at the 2014 SECON
conference in Singapore.
SECON is the IEEE International Conference on Sensing, Communication
and Networking. The paper, titled, “MUTE: Sounding Inhibition in MU-MIMO WLANs,” came in first out of over 300 submissions.
“The work is on Multi-user MIMO in IEEE 802.11ac-based networks and
the efficiency of the sounding procedure. Hopefully, this work will influence
the way channel feedback acquisition is performed in the standard,” lead author
Oscar Bejarano said.
Multi-user MIMO is a technique that leverages multiple antennas at a
transmitter to serve multiple devices simultaneously. For example, an Access Point
(AP) that serves multiple users at the same time instead of sequentially, one
at a time, as it is done in legacy systems.
In general, an access point consists of a device that allows other
wireless devices (users) to connect to the wired infrastructure, and commonly,
to the Internet. Examples of user devices are cell phones, laptops, other
“With MU-MIMO, the AP can serve as many users as it has antennas,”
With MU-MIMO, the capacity of the network can potentially be
proportionally to the number of concurrently served users.
MU-MIMO requires the transmitter to have information about the channel between
all its transmit antennas and all the users, and it obtains the information via
a process called “sounding”.
Sounding is typically done before every single MU-MIMO transmission
and it is very time consuming, which means that the actual overhead to enable
MU-MIMO is very high. The team proposed a solution in which the AP can
alleviate this issue.
“MUTE is a protocol we have implemented to make MU-MIMO more
efficient. It strives to minimize, or temporarily eliminate the excessive overhead
associated with sounding. With MUTE, we try to avoid sounding whenever it is
not critical. To this end, we allow the AP to learn about the channel
statistics of all users in order to make a prediction about how much their
channels have changed. Consequently, if the system recognizes that certain
channels have remained relatively stable, the AP adjusts accordingly therefore
reducing the amount of time spent sounding the channel,” Bejarano said.
Their paper showed that in their testing they were able to use MUTE
to reduce the overhead sounding creates by almost 73%.
“The goal with MUTE is to make MU-MIMO much more efficient and push
the real system-level gains close to the gains shown in theory,” Bejarano
Congratulate the team here.