Cricket Communications parent Leap Wireless International switched on its first LTE service in Tucson, Ariz., today, marking the start of what the company described as a "multi-year transition" to the next-generation mobile broadband technology.

The service will eventually cover about 90 percent of Cricket's Tucson market and will be expanded to nearby Nogales, Ariz., sometime next year.

Leap said in October it would launch its first LTE trial markets before the end of this year. Its LTE service is slated to cover 25 million people by the end of 2012, eventually blanketing about two-thirds of its network footprint. The company has not provided further details about its planned market launches.

Leap did not release specifics about the new service’s upload and download rates but said its LTE data speeds “ranged from 5 to 10 times faster than current 3G data speeds.” Verizon Wireless’ LTE network averages 5 to 12 Mbps on the downlink and 2 to 5 Mbps on the uplink.

So far, Leap is only offering one device compatible with the service, the dual-mode Huawei Boltz USB modem. The modem runs on Leap’s LTE and CDMA EVDO networks and is expected to retail for about $150. Customers can pick from two monthly rates: a $50 plan that offers 5 GB of data with download speeds of up to 3 Mbps and a $60 plan that also offers 5 GB of data, but with faster download speeds of up to 6 Mbps.

The debut of the new high-speed wireless service will help Cricket better compete against prepaid providers MetroPCS and T-Mobile USA, who both offer services marketed as 4G through their respective LTE and HSPA+ networks. The speeds of MetroPCS' LTE service are somewhat restricted by its limited spectrum holdings.

As a prepaid provider, Leap must keep a tight rein on spending to avoid raising prices at its Cricket subsidiary. Its capital expenditures are expected to be between $425 million and $475 million this year on the cost of its LTE build and ongoing maintenance of its 3G service.

Leap President and CEO Doug Hutcheson said that the company would roll out its new LTE network "in a thoughtful manner and on a timeline that is appropriate for our value-conscious customers."

Leap made plans last spring to use LightSquared’s proposed wholesale LTE network for roaming. That strategy is likely now on the backburner, since the launch of LightSquared's network has been delayed after it was found to cause widespread blackouts in GPS service.