AT&T Will Soon Boost Upstream Wireless Speeds > Still behind Sprint and Verizon

Still behind Sprint and Verizon

Then they will start sending the actual phone calls over the WiMax Digital feed, ultimately eliminating cell towers.

The Difference is distance. Wimax can go much farther than the existing Cellular system. "WiMAX will blanket a radius of 30 miles (50 km) with wireless access." »computer.howstuffworks.com/wimax2.htm

So, you are half right. They will use existing towers (because they own them already) but most all towers will not be needed. They will be able to cut cost on towers, were as raise cost on network infrastructure due to the huge demand on the WiMax Towers that serve a large service area.

30 miles is only best case and if you have line-of-site. In cities, WiMAX will only get about 4-6 miles and probably less in areas with rough terrain or lots of tall buildings.

But WiMAX transmitters don't need to entirely reside on existing cellsites. There could be WiMAX repeaters that get LOS to a tower 10 miles away and provide WiMAX w/out LOS to the neighborhood or a building. Repeaters could existing on city lightpoles.

Sprint said they will put 80% of WiMAX sites on existing cellsites, so I'm guessing the rest could be repeaters, perhaps on lightpoles.

Down the road, people will be able to buy their own repeaters or femtocells. So say you live in a high rise condo building, you could add a WiMAX repeater on top of the building that gets LOS to a WiMAX site miles away and then give great signal to your building - great latency too.

Exactly. There's a capacity vs. distance issue with putting much beyond a few miles in most cases. While Clearwire/Sprint have ~100MHz of spectrum (that's a lot!) you can't cover a city like Los Angeles with one or two sites.
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