Soft-TDMAC: A
Software-based 802.11 Overlay TDMA MAC Protocol with Microsecond Synchronization
Petar Djukic
Department of Systems and Computer Engineering
Carleton University
Friday, May 7, 2pm
Location: BAB024 (Bahen Centre Basement)
Abstract:
We implement a new
software-based multi-hop TDMA MAC protocol (Soft-TDMAC) with microsecond
synchronization using a novel system interface for development of 802.11
overlay TDMA MAC protocols (SySI-MAC). SySI-MAC provides a simple,
kernel independent, message based interface for overlay MAC protocol
implementations to schedule transmissions, send packets, and receive packets.
The key feature of SySI-MAC is that it provides near deterministic timer
scheduling and transmission times, which allows for implementation of highly
synchronized TDMA MAC protocols. Building on SySI-MAC's predictable
transmission times we implement Soft-TDMAC, a software based 802.11 overlay
multi-hop TDMA MAC protocol. Soft-TDMAC has a synchronization mechanism, which
synchronizes all pairs of network clocks to within microseconds of each other.
Building on pairwise synchronization, Soft-TDMAC achieves tight network-wide
synchronization. With network-wide synchronization independent of data
transmissions, Soft-TDMAC can schedule arbitrary TDMA transmission patterns.
For example, Soft-TDMAC enables schedules that decrease end-to-end delay and
take end-to-end rate demands into account. We summarize hundreds of
hours of testing Soft-TDMAC on a multi-hop test-bed, showing the
synchronization capabilities of the protocol and the benefits of flexible
scheduling.
Bio:
Petar
Djukic received B.A.Sc., M.A.Sc. and Ph.D. degrees from the University of
Toronto in 1999, 2002 and 2007, respectively. From 2008 to 2010 he was a
postdoctoral researcher at the Department of Systems and Computer Engineering,
Carleton University, Ottawa, Canada. From 2007 to 2008 he was a postdoctoral
researcher at the Department of Computer Science, University of California,
Davis. From 1999 to 2001 he worked as a software designer in Ottawa, Canada. His
research interests are in wireless multi-hop scheduling, radio access network
resource management, and testbed implementations of new wireless MAC protocols.
Host of Talk:
Shahrokh Valaee (valaee@comm.utoronto.ca)