FET Knee voltage and Pavg calucation

Hi
1. How to determine exact knee voltage of FET( ex of MRF8S9100H)?
2. what is IDQ and P_Avg. datasheet say's following information

"typical GSM EDGE Performance: VDD = 28 Volts, IDQ = 700 mA, Pout = 45 Watts Avg."
is IDS_avg =pout_avg/vdd =1.607 A, then how to determine IDS_peak and P_peak.

thanks