A string of attacks may eventually force Qualcomm to redefine its famous patent licensing model, one which has helped to shape the economics of the mobile device industry in the 3G and 4G eras. This week, the latest blow came when a South Korean court rejected the US chip giant’s request to reverse an antitrust ruling made in December. Meanwhile, Apple is challenging the very basis of Qualcomm’s lucrative licensing business and the US Federal Trade Commission (FTC) has joined the line of international agencies probing for possible anti-competitive activity. Amid all this turmoil, Derek Aberle, Qualcomm’s president and the man most closely associated with the company’s licensing business, is to leave the firm at the end of this year,…