To me 'choppy' indicates a problem with the copy of the game you have more than connectivity. Have you tried borrowing another copy of the game, or installing MP to your hard drive?
My only other thought is if you are going in via wifi to switch out to hardwire. If thats not possible then change the wireless channel on your router.
But as I said, choppiness sounds more like you have a duff copy of the game...
Can't believe i'm saying this, blops 2 plays better, what???, 0-o.
I've noticed problems since the last patch but it could be one or more of the following:
Every COD has played this way. Lag compensation has always been an issue but I've noticed a couple of differences with Ghosts, the maps are larger so when I see the lag compensation is working against me I adapt with a load-out for distance and camp/defend an area/path. Sometimes this doesn't work because, even though I have the enemy locked on with a thermal scope, the kill-came shows my bullets magically going around the enemies body. Like he's got an invisible shield that deflects the bullets away when they get close. In older versions I could go prone and this would add precision to my shot, but not in this game.
I've also noticed a pattern in matchmaking where I go through periods of being matched with players that have a lot higher k/d than mine. My team will have all the lowest k/d and the opposing team will have 3+ k/ds. Everyone on my team goes 10-33, 6-38... and the other team beast out. After an hour or so of playing these types of matches, matchmaking switches and all of the sudden I'm working it out.
It sucks but it is what it is. COD (since MW2) has always been like this and it will never change. While we play for enjoyment of the competition, COD is a money making business. Decisions will be made to produce the largest return on investment at all cost whether your game play is fair or not...
There's certain solution to reducing lag. If you haven't tried any yet or might need more solutions there are more available:
It can work with any game, it's about lag in general, really.