802.16e mobility vs. 802.16d

[dolphin558]

I am doing research on potential wireless trends and I am trying to get my head wrapped around the mobility aspect of 802.16. If I can walk/drive for miles with a laptop within a 802.16 enabled network and not lose broadband connectivity, how is that different than mobile connectivity under 802.16e?

When I was in college I could walk around the campus LAN (and I'm sure one can walk within a internet cafe without losing one's connection) with access so obviously mobile broadband connectivity isn't new. I suppose the source of my naivete lies with an understanding of 802.16e. Is it that 802.16e is designed for global mobility (like cellphones) rather than metropolitan wide mobility?

Any help you all can provide is appreciated. Thanks!

[Planet]

This article recently posted here on WiFi Planet refers to what your talking about. http://www.wi-fiplanet.com/news/article.php/3606126

[M/Q]

Planet's article was interesting, but I think I can help your understanding by explaining a few concepts.

First, comparing mobility in a Internet cafe or even a campus WLAN and 802.16 is not a good idea. The reason is that 802.11's main drawback is its inability to allow intelligent roaming between access points and or networks. Your ability to roam the campus using 802.11 was arrived at with a great deal of effort and aftermarket devices to enable seamless or nomadic roaming.

Now onto 802.16. First 802.16 and 16/a were designed to create high speed point to point backbone connections. But like anything else, techys including me like to push the envelope and have been using the protocol for other than its designed parameters.

Also it is common knowledge that the telecomms are working very hard to gain a foothold in the broadband data network realm. So companies, WISP's, and people who have invested a great deal in the 802.XX protocols want to be able to compete. The jury will be out for quite awhile as to who will win this battle, but my money is on the telecomms, just because they have the infrastructure in place. I am hopeful it will be a combination of both, though.

So, that is where 802.16e comes into play. It addresses many of the mobility issues that are not addresses in 16a. There is another workgroup for 802.20 that is similar and addresses some of the same issues.

http://www.wi-fiplanet.com/columns/article.php/3072471

Also the protocol addresses some of the same problems found when roaming using 802.11 that I mentioned earlier. If you wnat to get into the details of the changes, they center around changes to the lower three layers of the OSI model and the management of how they are controlled. (CSMA/CD versus CSMA/CA and beyond)