1、QUESTION ITU-R 207-4/3Propagation data and prediction methods for satellite mobile andradiodetermination services above about 0.1 GHz(1990-1993-1995-1997-2000-2009)The ITU Radiocommunication Assembly,consideringa) that there is a requirement for methods to estimate the field strength or the transmis
2、sion losswhen planning mobile and radiodetermination services using satellites;b) that a number of administrations are studying satellite systems for aeronautical andmaritime safety, radiodetermination, communication and control;c) that there is considerable interest in providing communication servi
3、ces to handheld andvehicular terminals with mobile-satellite systems;d) that for VHF, UHF and SHF systems involving satellites, both the ionosphere andtroposphere may affect propagation, as well as reflections from the ground, sea and/or man-madestructures;e) that for land mobile-satellite systems,
4、blockage and shadowing will affect propagation;f) that there is a requirement for propagation data and modelling for all path elevation andazimuth angles, especially for systems employing constellations of non-geostationary satellites;g) that knowledge of fade-duration and non-fade-duration distribu
5、tions is of particularimportance to satellite mobile and radiodetermination systems;h) that a number of mobile-satellite systems sharing the same frequency band will beintroduced;j) that frequency-selective fading and delay spread are important aspects of the propagationchannel which must be taken i
6、nto account in the design of digital wideband mobileradiocommunication and navigation systems,decides that the following Questions should be studied1 To what extent does the field strength or transmission loss depend on the nature of terrain,the effects of vegetation and man-made structures, antenna
7、 location, frequency, polarization, angleof elevation and climate; and how do these factors affect the selection of frequencies and wavepolarization for such systems?2 What are the effects of the local environment for handheld and vehicular terminals andpersonal communication systems?- 2 -3 What are
8、 the effects due to multipath propagation and Doppler spread changes, and how dothese depend on the parameters listed in 1?4 What is the most suitable form of prediction method, for each radio service, for use in thepreparation of national and international frequency plans?5 What are the characteris
9、tics and effects of land- or sea-reflection and multipath fading onradiocommunication or radiodetermination signals transmitted by satellites, both geostationary andotherwise, for the use of land vehicles, aircraft and ships?6 What propagation data may be collected for modelling, statistical charact
10、erization andmitigation of tropospheric and multipath-induced impairments, especially for low elevation angleslant paths, as a function of sea or land surface state (wave height or terrain irregularity), satelliteelevation angle, antenna radiation pattern, local site clearance and environment, inclu
11、ding terrainand vegetation blockage and shadowing and frequency?7 What is the method for estimating signal-to-interference ratio where both wanted andunwanted signals are affected by multipath fading?8 What are the advantages of physical-statistical propagation models for the characterizationof the
12、radio channel in multiple environments for land mobile satellite systems?9 What are the methods to model the propagation channel and evaluate performanceimprovement due to diversity (satellite, polarization, antenna) and multiple-input-multiple-output(MIMO) techniques for mitigation of propagation impairment models in satellite mobileradiocommunications?further decides1 that the available information should be prepared as a new Recommendation;2 that the above studies should be completed by 2013.NOTE 1 Priority will be given to studies relating to 1 and 2.Category: S2
