MetroPCS shareholders have voted in favor of the proposed merger deal with T-Mobile USA, Reuters reported. The approval comes only after Deutsche Telekom was forced to sweetened its offer for the wireless carrier after shareholders were advised to vote against the original proposal. Federal regulators at the FCC and Justice Department voiced their support for the merger in March, and the MetroPCS board unanimously approved the deal earlier this month. The merger will help T-Mobile expand its 4G LTE network to cover more than 200 million customers in the United States by the end of 2013. The deal is expected to close later this year.