Estimation of NCW Path Loss Error: With Gaussian Distributed RF Parameter Inaccuracies

The Network Centric Waveform (NCW) implemented on the RMPM-1000 modem relies on nominal values of radio frequency (RF) parameters in its database and measured signal-to-noise ratio (SNR) to calculate path loss. Some parameter inaccuracies and measurement errors are always present. Hence, the predicted path losses can never exactly match the actual channel. In order to assign the proper EIRP, modulation, code rate, and data rate for NCW, the predicted path losses should be as close to actual as possible. Thus, an understanding of the error in the path losses as a result of errors in the parameters and SNR measurement is important to NCW operations. This paper shows a method to estimate how much deviation can occur in path loss calculations from RF parameters and SNR measurement errors. RF parameter errors are represented by additive Gaussian random variables with small deviations that are reasonably observable in practice. Furthermore, SNR estimation error is softly bounded by the limits set in MIL-STD specifications. Using Monte Carlo simulations, the RMPM-1000's calculated path losses are sampled for 5000 independent trials. The path loss errors are then plotted as probability density functions (PDF). When an operator observes path loss error beyond the PDF, there may be other factors which may influence path loss calculations such as significant channel interference.