The default Wi-Fi name will be the one mentioned on the mode label if that is not getting displayed and you are looking for the default Wi-Fi network name you need to perform hard reset on the modem for 15- 30secs. After resetting the modem will go to default setup any custom settings will be removed so use the default network name and password  to connect to your network. After connecting device to the modem default Wi-Fi network follow the steps mentioned on the below article

http://arris.force.com/consumers/articles/General_FAQs/SVG2482AC-First-Time-Installation