Are you using a wired connection? Because usually, a wireless connection can be crappy. I also suggest that you visit this Activision Support article: Activision Support.. Just check it out and see what can help you.
Can you please provide us with the NAT type and bandwidth that registers in game? Multiplayer>Options>System info. While in Options, press the Select button on your controller and System info will display on screen. You can get the requested info from that screen.
As others have stated, try rebooting your router.
Additionally, you may need to establish a static IP address and port forward. If you have questions on how to port forward, please contact your ISP or the router manufacturer. Here are the port numbers you will need Activision Support