According to the NS2 guidelines in ./ns-2.35/mac/wireless-phy.h file, Pt_ value cancalculate as follows:
// Assume AT&T's Wavelan PCMCIA card -- Chalermek
// Pt_ = 8.5872e-4; // For 40m transmission range.
// Pt_ = 7.214e-3; // For 100m transmission range.
// Pt_ = 0.2818; // For 250m transmission range.
// Pt_ = pow(10, 2.45) * 1e-3; // 24.5 dbm, ~ 281.8mw
Can someone explain how to calculate for 1000m?