1、HTTP:/WWW.ITU.INT/DMS_PUB/ITU-R/OPB/QUE/R-QUE-SG03.209-2002-MSW-E.DOC 16.10.03 14.07.10QUESTION ITU-R 209/3Variability and risk parameters in system performance analysis(1993)Q. ITU-R 209/3The ITU Radiocommunication Assembly,consideringa) that for the proper planning of terrestrial and Earth-space l
2、inks it is necessary to haveappropriate parameters for the formulation of performance criteria of radiocommunication systems;b) that the “average annual worst month” has been defined as the long-term statistic relevantto performance criteria referring to “any month”;c) that due to the stochastic nat
3、ure of propagation effects in radiocommunication systemsthere is a need for information on variability of these effects, with respect to the long-term statistic,for various periods of reference;d) that there is a need for an unambiguous formulation of variability parameters to allowproper cost and p
4、erformance trade-offs to be made in the analysis of system reliability, availabilityand quality,decides that the following Question should be studied1 What is the variation of propagation effects with respect to the long-term cumulativestatistic for various periods of reference?2 What are the period
5、s of reference to be specified for the formulation of risk parametersassociated with the variation of propagation statistics?3 What are the parameters most suited to the formulation of confidence limits and risksassociated with the specification and estimation of system performance?4 What are the procedures for the calculation of the parameters defining statistical variationof propagation effects in radiocommunication systems?_
