Scott’s Weblog

An overlay MAC layer for wireless networks

July 13th, 2006

http://www.citeulike.org/user/scottr/article/503372
This is an interesting paper, which is quite recent, and deals with the same kind of issues I am currently looking at. The main crux of the article is that in order to do MAC research we should be using an overlay approach - implementing the MAC in software on top of the existing 802.11 MAC - as it makes it possible to test the MACs in real world environments. The argument for the need for testing MACs in the real world is one that I would like to persue. They also argue that replacing the MAC layer is too costly, and so they present the overlay solution. The MAC they present using this technique allocates timeslots using a distributed algorithm, and increases the total throughput of the system. The paper also outlines some of the current problems with 802.11 in terms of unfairness, etc.
This sounds similar to what I want to do with the Atheros cards, although it does have differences. In this paper, they are essentially doing scheduling of writes to the NIC, but still using 802.11 for framing, addressing, etc. In my system, I would like to run an entirely separate MAC using broadcast 802.11 frames. Obviously this has quite a bit of overhead, but allows cheap deployment of the protocol, and allows us to (mostly) test it in a (mostly) real-world environment. The WAG cards provide us with a way to run the entire MAC on the hardware without 802.11 encapsulation, but that is a very expensive option. More to come on this later.

Entry Filed under: Literature Review, Ph.D