AT&T on Sunday said it has entered into a agreement to purchase T-Mobile USA from Deutsche Telekom in a cash and stock deal worth an estimated $39 billion.

[ad#Google Adsense 300×250 in story]AT&T said its customer and T-Mobile customers will see improved service and voice quality because of the deal, due to additional spectrum and increased tower density. According to the companies, AT&T will gain cell sites equivalent to what would have taken on average five years to build without the transaction, and double that in some markets.

The deal will also bring AT&T’s 4G LTE technology to an additional 46.5 million Americans. This includes rural and smaller communities, making 4G available to 294 million people or 95 percent of the U.S. population, according to AT&T.

The acquisition is subject to regulatory approvals, but is expected to close within 12 months.