Wireless carrier T-Mobile has announced new partnerships with Ericsson and Nokia Siemens Network to help the carrier build its upcoming 4G LTE network, the company announced today.

T-Mobile has been hurt more than any other major carrier by the absence of Apple’s iPhone and its lack of a true 4G network. The company has branded its HSPA+ network as “4G” but clearly that didn’t work well enough to keep subscribers coming back for more. T-Mobile lost a whopping 802,000 contract customers in its last quarter, and its revenue fell 3.3 percent.

The company’s 4G LTE network, which will cost $4 billion to roll out, will launch some time in 2013. In a multi-year agreement, Ericsson and Nokia Siemens will support the LTE network by providing “state of the art, Release 10 capable equipment” at 37,000 cell sites across the U.S. to increase signal quality.

AT&T and Verizon have already deployed their LTE networks, which are significantly faster than T-Mobile’s HSPA+ faux-4G offering. Sprint has plans to roll out LTE in the middle of the year.

On top of the partnerships, T-Mobile has also expanded its HSPA+ network to 229 markets in the U.S. The carrier added Little Rock, Ark.; Springfield Mo.; Hattiesburg, Miss. and Madison, Wis. to its HSPA+ 42 network. The HSPA+ network will provide a stop-gap solution while T-Mobile customers get access to 4G LTE access and devices.