1、QUESTION ITU-R 203-4/3PROPAGATION PREDICTION METHODS FOR TERRESTRIALBROADCASTING, FIXED(BROADBAND ACCESS) AND MOBILE SERVICES USINGFREQUENCIES ABOVE 30 MHZ(1990-1993-1995-2000-2002-2009)The ITU Radiocommunication Assembly,consideringa) that there is a continuing need to improve and develop field str
2、ength prediction techniquesfor the planning or establishing of terrestrial broadcasting, fixed (broadband access) and mobileservices using frequencies above 30 MHz;b) that for terrestrial broadcasting, fixed (broadband access) and mobile services, propagationstudies involve consideration of point-to
3、-area and multipoint-to-multipoint propagation paths;c) that present methods are based largely upon measurement data and there is a continuingneed for measurements within this range of frequencies from all geographical regions, especiallydeveloping countries, to increase the accuracy of the predicti
4、on techniques;d) that the increasing use of frequencies above 10 GHz requires that prediction methodsshould be developed to meet these new requirements;e) that digital systems involving wideband transmission are being introduced to bothbroadcasting and mobile services;f) that reflected signals must
5、be taken into account in the design of digital radio systems;g) that there are increasing demands for frequency sharing between these and other services,decides that the following Questions should be studied1 What field strength prediction methods can be used for terrestrial broadcasting, fixed(broa
6、dband access) and mobile services in the frequency range above 30 MHz?2 How are the predicted field strengths, multipath and their temporal and spatial statisticsinfluenced by: frequency, bandwidth and polarization; length and properties of the propagation path; terrain features, including the possi
7、bility of long delayed reflections from off-great circlehillsides; ground cover, buildings and other man-made structures;2 atmospheric constituents; height and surrounding environment of the terminating antennas; directivity and diversity of the antennas; mobile reception; the general nature of the
8、propagation path, e.g., paths over deserts, seas, coastal areas ormountains and, in particular, in areas subject to super-refractive conditions?3 To what extent are propagation statistics correlated over different paths and frequencies?4 What methods and parameters best describe the coverage reliabi
9、lity of these analogue anddigital services and what information beyond field strength data is necessary for these purposes,e.g. the “intelligence” incorporated in a frequency agile system?5 What methods and parameters best describe the propagation channels impulse response?further decides1 that the available information should be prepared as a new Recommendation.Category: S1
