Toronto Networking Seminar

Organized by Department of Computer Science and Department of Electrical and Computer Engineering, University of Toronto



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)