optimum value of IIP3

hi to all
i want to know what is the optimum value for IIP3 for a device and from where i can get the specifications for ISM band 2.4 GHz

as high as possible
it depends on a lot of things: the interference profile, the signal modulation technique you used, etc

Not always the highest possible IIP3 will meet the required (or specified) IIP3.

You have to follow the RF system specification for a specific 2.4GHz ISM communication system, which can be Bluetooth, WLAN, WiMAX, RFID, etc…

I guess this mainly related to blocker strength or blocker compliance.
In a system design when we check for all other parameters wrt to IP3 we get lower value but when subjected to blocker the required IP3 will be higher and is the limiting factor.