A recent filing at the Wi-Fi Alliance reveals that the Samsung Galaxy S II will debut with a Dual-Band 2.4GHz/5.0GHz Wi-Fi radio. This support affords the device compatibility with both older 802.11a access points, and newer 802.11n access points that have dual-band radios. The less-congested 5.0GHz frequency can also yield a higher speed connection.
The device boasts full 802.11a/b/g/n compatibility, giving it access to the widest range of Wi-Fi networks possible. Unfortunately the filing also reveals that there is only a single Wi-Fi antenna present in the device, meaning it will not be capable of utilizing a multiple-input, multiple-output (MIMO) connection.
MIMO is the technology that allows 802.11n devices to connect at speeds up to 450Mbps by utilizing multiple carrier signals over multiple antennas. Without this support, the Galaxy S II’s Wi-Fi radio will be limited to a maximum speed of 150Mbps. The device’s lack of MIMO support will likely not hurt its overall maximum speed, as the achievable transfer rate is also limited by the CPU and other software running on the device.
5.0GHz support will be a welcome addition for many owners of 5.0GHz access points, as with the heavy proliferation of Wi-Fi networks the 2.4GHz band can become so overloaded that range and speed is significantly impaired.
Source: Wi-Fi Alliance