I've got accespoint with TURBO mode support of course it is based on ralink chipset so how can I set turbo mode on this driver ? It is possible ?
Yes it is possible. Run (as root) "iwpriv wlan0 set TurboRate=1". Alternatively, RutilT lets you set it too.
You will find similar commands in the file "iwpriv_usage.txt" in the source package.