Mobile operator O2has struggled to support its customers in the latter half of 2009, its chief executive admitted.\nIn an interview with the Financial Times, Ronan Dunne said that he had been disappointed with the performance of O2's network since the summer, explaining that the company was struggling to cope with the rising number of mobile apps, particularly those associated with Apple's iPhone. He apologised to customers for the problems they'd been facing.\nHowever, Dunne said that the company was upgrading its network to cope with the demand adding that the problems had been mainly confined to London, He said that the company had a three point plan to improve performance for its customers.\nDunne said that O2 has been working with Nokia Siemens Networks, to make modifications to the infrastructure to improve the way that it can handle the combination of voice and data traffic. He said that the company was also installing an additional 200 mobile base stations in London to support an increased level of traffic and finally, he added, the company was liaising with handset manufacturers, including Apple and RIM, to learn more about the applications that were placing heavy demands on the network.\nO2 owner, Telefonica, has also made a purchase of its own in the mobile applications market. The company announced that it has acquired mobile VoIP company Jajah to improve O2's own communications portfolio. Jajah will continue to operate under its current brand name.\nIn a statement, Trevor Healy, CEO of Jajah, said: "This is a very exciting union of a young, innovative company with one of the largest integrated communications companies in the world. Together, we look forward to creating the next generation of communication."