3G contention ratio

[Guest Samsonite]

If you have a number of 3G devices in the same location, is the datarate given to each unit lower than if a single unit is blasting away?

my work is soon to offer a 3G industrial modem and these sorts of questions have started to rear up. We dont have any proper hardware just yet but i am curious as to how fast concurrent connections in the same location will stay at. Is 384kbps available irrelevent of number of devices connected to the same cell?

i am doing a trawl around the various tech sites to get some information on this but a real world test is much more useful...

any info greatly appreciated...