Mobile phone maker Sony Ericsson expects to at least maintain its 4 percent share of the global handset market through an improved product portfolio, chief executive Bert Nordberg told Dow Jones Newswires. However, the company’s main objective is increasing profitability, with boosting market share – in terms of both value and volume – a secondary priority, Nordberg said. The vendor also expects to focus on Android as its main operating system, but will continue to support Symbian and Windows.