Unplug all network devices including the PS3 system. Wait a few minutes before turning them back on – this will refresh the network settings. Check your router manual — to connect with a PS3 system, your router must support 802.11b or 802.11g wireless protocols. If you are using an 802.11n router, it should be set to mixed mode.
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Amazon.com: ps3 wireless internet adapter
With the exception of the original 20GB model, the PlayStation 3 video game consoles, the PS3 Slim consoles, and the PS3 Super Slim units all include built-in 802.11g (802.11b/g) Wi-Fi wireless networking. You don't need to purchase a separate wireless game adapter to hook up a PS3 to a wireless … Xbox Support
Oct 15, 2011
Unable to Connect a Sony PlayStation 3 (PS3) to a Wireless