why 3G just isn't ready

if you are not a geek, you will most definitely be bored by the following post.

we were testing out our new feature in lab the today when we made a rather startling realization about wireless data services. That realization is that no one uses wireless data in a way that will differentiate 3G from EDGE and EDGE from GPRS. Now here's the details of why. Let's just say that the average file size being sent wirelessly is 25k (reasonable given that a picture from a camera phone is anywhere from 10k to 50k). TCP window size is 8192 bytes (default on most ftp servers). Round trip delay is roughly 8 block periods at 20ms/block period. Now, if you're familiar with the protocol, tcp has what is called 'slow start'. Meaning, it will wait for the first tcp packet it transmitted to be acked before it doubles it's window size. So server tranmits packet a, mobile acks packet a, server tranmits b & c, mobile acks b &c, server tranmits d,e,f,g, mobile acks them, etc up until the size of all the packets is equal to the window size...then you're limited by your round trip delay, which is constant in GPRS, EDGE and UMTS. But by the time you even get to that max window size where you can take advantage of how fast you can transmit your large payload, your transfer is typically over and the difference in data rates becomes negligible. So until people start downloading Redhat ISO's or streaming media into their cars, the business case just isn't there because most people won't pay the outrageous data fees that wireless companies are demanding for such high bandwidth applications. And they continue to market 3 and 4G technologies like they will save the world...

End geek dissertation.