Infinite Loading Screen Battlefield 3 PS3

Okay I would say you should clear your gamedata first:

Try to deinstall the HD package for BF3, sometimes this pack can cause glitch issues.

Try to reinstall the game, but start it without the expansion packs:

1. Delete the BF3 game data (not the savegame data)
2. After that, you can run a PS3 file system scan
3. Clean the BF3 disc
4. Install BF3 without expansion packs
5. Re-activate online pass
6. Start the game and play several matches.
7. If that worked, install B2K etc.

If it's related to your internet connection aka the PSN Media Server Connection, you should check following steps:

The Media Server Connection allows other devices to connect to your PLAYSTATION 3. Often, the Media Server Connection is known to cause issues when players try to connect to the Internet for online game play.

1. Access your Xross Media Bar menu
2. Navigate to Settings
3. Select Network Settings
4. Select Media Server Connection and choose the Disable option.

Turn off the Media Service connection can slower your PS3 internet connection (especially for downloading).

Please enable the following online ports on your connection:
TCP: 80, 443, 9988, 10000-10100, 17502, 42127
UDP: 3659, 14000-14016
For specific instructions on how to open your ports, please visit http://www.portforward.com/ or contact your router manufacturer