Sony Ericsson Mobile Communications Ltd., the mobile-phone joint venture of Sony Corp. and Ericsson AB, said first-quarter profit more than tripled on demand for models with Walkman music players and cameras. Net income climbed to â‚¬109 million from â‚¬32m. a year earlier, London-based Sony Ericsson, the world's fifth-largest maker of cellular phones, said. Sales rose 55 percent to â‚¬1.99b. from â‚¬1.29b. Sony Ericsson is tapping developed markets in Europe and the US with its strategy of selling more expensive models such as music phones using Sony's Walkman brand. Nokia Oyj, the world's largest maker of mobile phones, said on April 11 it's selling more models with cameras and music players, helping first-quarter unit prices beat its forecast. Nokia reports earnings on April 20. "Going after the higher-end market is absolutely necessary in order to secure profit growth," said Yuuki Sakurai, general manager at Fukoku Mutual Life Insurance Co., which manages the equivalent of about $42b. in assets. Sony Ericsson had a global market share of about 6% to 7% in the quarter, Chief Executive Officer Miles Flint said in a phone interview from Paris. Pretax profit rose to â‚¬151m. from â‚¬70m. a year earlier.