Competition among smart phone makers is heating up at retail, in advertising and, increasingly, in the courtroom as handset and software makers wield patent lawsuits to protect their turf and slow down their rivals.

Though Apple’s iPhone changed the categoryin 2007 and still leads the market, there are a flood of rivals and copy cats making it difficult for smart phone makers to stand out to consumers or persuade them to pay more for their devices.

In turn, that has prompted a slew of patent disputes over all aspects of basic phone use, from the way a user swipes a touch screen to perform an action to the method a phone uses to extend battery life. Nokia is suing Apple, Apple is suing HTC, Microsoft is suing Motorola and more. Get the full story »