T-Mobile USA said Tuesday at CES that it would begin offering a nationwide unlimited plan to its prepaid customers for $70, as well a partnership with Major League Baseball (MLB) to become the sport’s official wireless sponsor.  

The company said that its Unlimited Nationwide 4G Data plan will be available with no annual contract starting today. The new plans will offer unlimited and talk, text and unthrottled data for $70 per month. 

CEO John Legere said T-Mobile’s Unlimited Nationwide 4G Data plan is by far the most popular plan amongst its users. In fact, nearly half (46 percent) of new customers opted for the new data plan in December 2012.

T-Mobile also said yesterday that it has signed an agreement to be the official wireless partner of MLB. Until now, America's pastime had been without a sponsor from the wireless industry. T-Mobile said it will be providing technology that will "enrich the MLB experience for both players and fans, inside and outside of the ballpark."  

Specifically, the carrier will provide a new on-field communication system powered by the carrier's network that will connect managers in select Major League dugouts to coaches in bullpens. This dugout-to-bullpen system will start to roll out in 2013. 

The MLB tie-up is at least a feather in the smaller carrier's cap. Larger rival Verizon Wireless is currently the official wireless sponsor for the National Football League. 

As T-Mobile hones its challenger strategy and upgrades its network in preparation for an LTE rollout this year, the company said it is also the first carrier in the United States to offer HD Voice on its nationwide network. T-Mobile said the new feature will dramatically improve in-call audio performance for customers with capable devices. 

In addition, T-Mobile announced network enhancements in new metro areas, including Denver, Los Angeles, San Diego and Virginia Beach, Va. The improvements are part of T-Mobile's $4 billion plan to modernize its existing HSPA+ network by improving signal strength and in-building coverage and re-tuning its airwaves to launch 4G service in an additional frequency, 1900 MHz, which is compatible with more devices, including AT&T's iPhone. 

T-Mobile says the network enhancements now reach 126 million people in 46 metro areas including major cities such as Atlanta, Boston, Chicago, Dallas, Detroit, Houston, Las Vegas, Miami, Minneapolis, New York, Philadelphia, Phoenix, San Francisco, Seattle and Washington, D.C. T-Mobile’s nationwide 4G network covers 229 metro areas reaching well over 220 million people.  

The company's new 4G Connect program was also announced, which features devices, such as notebooks and ultrabooks that come with an embedded cellular modem and are Internet ready. 

The first devices supporting 4G Connect include select Windows 8 notebooks and Ultrabooks from Dell and HP, including the HP Pavilion dm1 and Dell Inspiron 14z Ultrabook. 

Device pricing varies, but all-in costs for a device with the free connectivity begin at less than $500. Depending on which device is selected, customers can take advantage of up to 200 MB of free data per month for up to two years. Users who require additional data capacity can grab more bytes at $10 per GB.