Instructions
Check the settings on your Internet router to make sure everything is working properly. The most common cause of the transmission error in "COD" is a loss of Internet connection. See if your router loses its signal from time to time, which can happen with most routers. If no other device ever loses connectivity, then the router might not be the problem.
Examine the PlayStation's Internet settings to make sure it is connecting to the proper network. It's possible your console might be trying to connect to a different, weaker signal. If your router is working properly, check the Internet settings to make sure your network is the primary. If possible, use an Ethernet cable to connect your console to the router, as the connection will be more reliable.
Reset both the router and the console's connection settings if the problem persists. If you are still getting the transmission error, try resetting your router and your console's connection to see if that will fix the problem. To reset a router, just unplug it and then plug it back in. To reset the PS3's connections, disconnect from all networks you are currently using and, after your router has reset, make it your primary connection again.