Do this with your router at home. Connect to the router's IP address via Ethernet cable. You can get this from the router's manual (check also for the initial username and password to access the site). Go to the wireless setup from here, and change the name to something that you can recognise. Make sure that it is password protected. Save it so that it'll write itself to its flash memory (your network will briefly not work). Once this is done, open network preferences on your MBP and search for thisNEW network using WiFi (not your Ethernet connection). Select it and lock it. Disconnect the Ethernet cable, shut down / or put it to sleep, then restart and see if it works.