Initially it was believed that the Nexus would not be able to support LTE,but after a few small software tweaks the phone can now enable 4G LTE capabilities. Bad news about this for most Nexus customers is that “LTE band 4 (which covers AWS 1700 and 2100MHz spectrum)” is not supported outside of Nexus homebase, Canada. Verizon’s LTE network and the majority of AT&T’s use entirely different spectrum bands. AT&T uses AWS spectrum for some of its LTE network, but it’s not easy to find. According to users, this fix makes the Nexus an even better phone since Band 4 LTE is what that carrier will eventually rely on.
For now, the upgrade to the phone is considered on a hack , but there isnt anything preventing google from creating an upgrade.