10-04-2017, 07:45 PM
Presented By:
Bret Hull, Kyle Jamieson, Hari Balakrishnan
MIT Computer Science and Arti cial Intelligence Laboratory
The Stata Center, 32 Vassar St., Cambridge, MA 02139
ABSTRACT
Network congestion occurs when o ered tra c load exceeds available capacity at any point in a network. In wireless sensor networks, congestion causes overall channel quality to degrade and loss rates to rise, leads to bu er drops and increased delays (as in wired networks), and tends to be grossly unfair toward nodes whose data has to traverse a larger number of radio hops. Congestion control in wired networks is usually done us- ing end-to-end and network-layer mechanisms acting in con- cert. However, this approach does not solve the problem in wireless networks because concurrent radio transmissions on di erent links interact with and a ect each other, and be- cause radio channel quality shows high variability over mul- tiple time-scales. We examine three techniques that span di erent layers of the traditional protocol stack: hop-by-hop ow control, rate limiting source tra c when transit tra c is present, and a prioritized medium access control (MAC) protocol. We implement these techniques and present ex- perimental results from a 55-node in-building wireless sen- sor network. We demonstrate that the combination of these techniques, Fusion, can improve network e ciency by a fac- tor of three under realistic workloads.
read full report
http://citeseerx.ist.psu.edu/viewdoc/dow...1&type=pdf