wireless help: In the wireless industry, what is 4g? - Help.com

4g is the next level of data transfer the cell networks will eventually be trying out and hopefully releasing full scale. sprint is currently testing WIMAX partnered with another company. google WIMAX WIMAX however has not been successful as of yet the test markets have seen little success. This is in part due to the data thats being transferred to the consumers device experience issues with network traffic, meaning there are too many people on the tower using the internet at the same time. and since 4g will most likely assign each customer 3 megabytes to 12 megabytes per second the data load of everyone using the tower at once can bring the network to a crawl. Currently the standard on all networks is 3G which runsabout 1.2 megabytes per seconds on average. so basically 4g is just an upgrade to a much high internet connection but currently the cell towers running on all networks are not able to support that type of traffic or data load yet.

http://en.wikipedia.org/wiki/4G