More than 15 years after the cellular industry divided itself under different network technologies after a decade under a common standard analog technology, cellular carriers will once again will be on a common standard network technology called Long Term Evolution or LTE.
One of the advantages of GSM and newer HSPA networks is that phones can be unlocked and used on another carrier's network just by changing the SIM card. Subscribers on GSM and HSPA networks were not limited to the phones offered by their carriers.
Cellular carriers across North America are currently upgrading or planning to upgrade their networks to LTE. LTE phones use SIM cards just like older GSM and HSPA phones. Since many Canadian LTE subscribers on Rogers, Telus and Bell may be looking south of the border for unlocked LTE phones they like better than what their own carriers offer.
Unlike buying an unlocked GSM or HSPA phone, one thing that needed to be considered when buying an unlocked LTE phone is original carrier that sold the phone. All three of Canada's cell carriers offering LTE uses HSPA as their fall back legacy network for areas that do not have LTE coverage. LTE handsets originally sold by AT&T are universally compatible on all three LTE networks in both LTE and HSPA coverage areas.
Those phones originally used on Verizon and Metro PCS are another story. LTE equipment from Verizon and Metro PCS are designed to use CDMA as a fall back outside of an LTE coverage area. If an unlocked LTE phone from Verizon or Metro PCS is used in Canada it will only wherever there is LTE service available. If an attempt to use that phone in an area that doesn't have LTE service it will try to connect to any available CDMA network. The legacy CDMA networks on Bell, Telus, MTS or Sasktel will recognize the phone as being foreign from it's Electronic Serial Number or ESN. That phone's ESN will not have an active account with it's home carrier, an message "You are roaming on the Bell/Telus/MTS/Sasktel mobility network and cannot place calls at this time" message will be heard when attempting to make a call. Unlocked LTE devices can cost well over 500 dollars on Internet auction and classified sites, Now in the biggest way, buyer beware, and check to see if you live in an LTE coverage area first.