The problem with wireless data is that everyone in range shares the same bandwidth that’s available in the radio channel. Just like a wifi node and a 3G or 4G cell has a maximum aggregate throughput for all devices. This is contrast with wired and switched networks where (if the switch is fast enough) every node gets wire speed to another node at the same time.
In amateur radio we know this problem very well. I can use High Frequency radio, say in the 40m band to send email through servers hundreds or even thousands of miles away. The bandwidth is very limited, measured in hundreds of maybe a thousand bits per second. Sending even short text emails takes quite a while. Sending pictures is almost out of the question. While I am sending or receiving email no one else can use that frequency for hundreds or thousands of miles around. I am the exclusive user. Works fine when there are only a few people using that channel. Not so much when you have thousands trying to use it.
That is why it makes no sense to put 3G and 4G wireless cells very high. Too many people would share the same cell, rendering it almost useless. You want lots of small cells so you all get a bigger slice of the pie.
If google requires special base stations to talk to the balloons they can limit the number of nodes connecting at any one time. But the higher the balloons the fewer people can make use of the service. Lower is better in this case.
Well, we’ll see if we ever get to read some technical details about this project beyond a superficial journalistic article. The goals are lofty (pun intended) but physics has a nasty habit of not being impressed with good intentions and press releases.
The original article: http://news.discovery.com/tech/gear-and-gadgets/google-beam-internet-balloons-130617.htm#mkcpgn=fbsci1
Apologies for the poor puns.