(Telecompaper) Deutsche Telekom reported a strong improvement in second-quarter results, led by the performance of T-Mobile US. Revenue rose 15.3 percent to EUR 17.4 billion, and adjusted EBITDA increased 13.5 percent to EUR 5.0 billion. On an organic basis, revenue was up 5.7 percent, and EBITDA rose 6.7 percent. Net profit was little changed year-on-year at EUR 712 million, due to extra staff-related costs. The German operator invested EUR 2.6 billion in the first half, excluding spectrum licences, an increase of 17.2 percent from a year earlier, while free cash flow still improved 31.1 percent to EUR 4.1 billion. Deutsche Telekom confirmed its guidance for 2015 adjusted EBITDA of around EUR 18.3 billion and free cash flow at EUR 4.3 billion.