Tuesday, February 27, 2007

Optimizing the Placement of Internet TAPs in Wireless Neighborhood Networks

Optimizing the Placement of Internet TAPs in Wireless Neighborhood Networks, R. Chandra, L. Qiu, K. Jain, M. Mahdian. ICNP'04.

This is strange, the version I downloaded has the first two authors inverted. It is titled Optimizing the Placement of Integration Points in Multi-Hop Wireless Networks, but it really looks like the same thing. Maybe a journal version or something. I am putting up the reference in the actual ICNP'04 proceedings, but I read the other version.

Anyhow, the paper is a follow-up to On the Placement of Web server replicas, whom Lily Qiu also co-authored. The funny thing is that I am basically following the same thought process: a student is looking into designing CDNs into wireless mesh networks, and has me reading this literature so I can be useful. Then I think: hey! CDN servers, or wired gateway, same thing, that's where the data is coming from. So on from CDN servers to "integration points" and "wired access points" which lead to a google search, where we found this. Only 3 years too late, of course.

The paper follow the same architecture as the previous one: convince the reader that you cannot really solve the problem, it's NP-hard, so you'll provide a set of heuristic strategies and test and compare them. The strategies are similar: random, greedy, etc. Of course, the wireless set-up introduces all kind of kinks which make the paper interesting and the contribution significant over the previous work.

There is a proof of the closeness of the strategy to the optimal solution, and a great match between a computable lower bound and the greedy strategy (which both book-end the optimal strategy), so the solutions proposed here are working well.

Having said enough good about the paper, I can share my little giggle. My version of the paper includes the following sentence:

In comparison [to TDMA scheduling schemes], in this paper we look at more general and efficient MAC schemes such as IEEE 802.11

More general, maybe, but more efficient? The MAC layer ends up being abstracted away sooner afterwards, so it does not really matter.

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