I have an app that checks the results of matches in real time.
I want to be able to poll the server every minute to see if there has been any updates on the match. I
Primarily you should consider push notifications.
Background mode for location services is the alternative. Maybe it can work during a game. It does drain battery thou.
You'll not be allowed to do any form of real-time polling in a background task on Windows Phone.
However, if you keep your application open in the foreground, you can do all the polling you like.
I know whatsapp uses a hack to do this, using the audio sdk. You could try to see if that works for you. Here is an example of the audio sdk http://msdn.microsoft.com/en-us/library/windowsphone/develop/hh202978(v=vs.105).aspx