The biggest issue with 4G networks is handover. When you’re speeding down the highway, your cellphone and wireless devices constantly hop from station to station, picking up connectivity as you go along. In a perfect world, this handover is seamless but, as we all know, in the real world it isn’t poifect.
Nortel just tested their LTE standard with vehicles moving between coverage sites at about 60 miles an hour, a fairly large breakthroug in the 4G LTE spae. When will you get to use your own LTE dongle? Not in a while, sadly, but keep dreaming.