Just now started to happen.
Happened at first when finding a game, it just disconnected me and set me back to the main screen. My connection was restored once I went into my wireless adapter's settings (without changing anything)
Happened second time in the middle of a match. Was disconnected, hit the big green X button and did Connect to Xbox Live and my connection was restored.
Not sure if it was a problem on my end (my wireless adapter has been in use hours a day ever since they came out) or if it is something wrong with the game.