Microsoft Corp, the software maker seeking to challenge Apple Inc and Google Inc's dominance in smartphones, agreed to share patents with handset-maker Samsung Electronics Co. Microsoft will receive royalties for mobile phones and tablets built by Samsung that use Google's Android operating system, according to a statement today. The companies also agreed to cooperate on the development and marketing of Windows Phone, Microsoft's mobile software. Smartphones with Microsoft's revamped Windows Phone 7 software have struggled to compete with Apple's iPhone and Android-based devices. Microsoft, whose Windows Mobile software licenses were doubling annually before the iPhone was introduced in 2007, announced an alliance with Nokia Oyj in February to develop smartphones. Microsoft, based in Redmond, Washington, fell 10 cents to $25.58 at 4 p.m. New York time in Nasdaq Stock Market trading. Suwon, South Korea-based Samsung added 0.4 percent to 807,000 won in Seoul trading.