1、 ITU-R RECMNxSM- SERIES 95 4855212 052b732 374 m Rec. ITU-R SM. 1133 7 RECOMMENDATION ITU-R SM.1133* SPECTRUM UTILIZATION OF BROADLY DEFJJWD SERVICES (Question ITU-R 205/1) (1995) The ITU Radiocommunication Assembly, considering that the Radio Regulations (RR) define over 40 different radio services
2、; that, narrowly defined services can unnecessarily restrict flexibility and limit spectrum utilization; that the RR defines some radio services as subsets of others; that the factors with respect to the utilization of broadly or narrowly defined services need to be delineated, a) b) c) d) recommend
3、s that, when considering the utilization of broadly defined services in a specific frequency band, administrations 1 should consider the factors in Annex 1. ANNEX 1 A guide to utilization of broadly defined services 1 Introduction This Recommendation considers the technical requirements for the util
4、ization of more broadly defined services. The relationship between radio services in terms of broader and narrower definitions is shown in Fig. 1. The objective of using broadly defined services is to increase the flexibility of allocations. The concept of using broadly defined services in this cont
5、ext does not necessitate the elimination of narrowly defined or subset services, but involves the use of the most broadly defined service possible, given the factors discussed below. * This Recommendation should be brought to the attention of Telecommunication Development Study Groups 1 and 2 (ITU-D
6、). ITU-R RECMN*SM. SERIES 95 4855212 0526733 200 = Rec. ITU-R SM. 1133 FIGURE 1 Relationship between radio services in terms of broader and narrower definitions Terrestrial services Fixed Aeronautical fixed Aeronautical mobile (R) - Aeronautical mobile (OR) r Aeronautical mobile Mobile +, Landmobile
7、 L Maritimemobile Note 1 Maritime radionavigation Aeronautical radionavigation Radionavigation - Radiolocation Radiodetermination The following setvices are not dejned by the Radio Regulations (R) as being pai of any grouping of services. Broadcasting Amateur Radio astronomy Meteorological aids Stan
8、dard frequency and time signal Nore I -The ship movement and port operation seMces are not subject to any table allocations. They are referred to in RR Appendix 18. Space services Land mobile-satellite Mobile-satellite Maritime mobile-satellite Aeronautical mobile-sateiiite (R) Aeronautical mobile-s
9、atellite (OR) L Aeronautical mobile-satellite -E Radiodetermination-satellite Aeronautical radionavigation-satellite _c Maritime radionavigation-satellite Radionavigation-satellite Radiolocation-satellite Earth exploration-satellite Meteorological-satellite The following services are not defined by
10、the RR as being part of any grouping of services. Fixed-satellite Broadcasting-satellite Amateur-satellite Radio astronomy Standard frequency and time signai-satellite Space operations Space research inter-satellite DO1 ITU-R RECMN*Sfl. SERIES 95 W 4855232 052b734 347 W Rec. ITU-R SM. 1133 9 In cons
11、idering the use of the broadly defined services, the following should be noted: broadly defined services can provide a simpler allocation process; the complexity of sharing and coordination is related to the number of services and the kind of services that are subsets of a broadly defined service; w
12、hile use of broadly defined radio services increases the flexibility of the allocation process, it may introduce more complex sharing within a particular frequency band. Hence there exists a trade-off between the flexibility and the complexity of sharing; use of broadly defined services may not resu
13、lt in higher spectrum efficiency. Especially when subset services with very different technical parameters (such as large difference in transmitter power) are together, degradation of efficiency may result: the safety aspects of services should be considered; it is possible that broadly defined radi
14、o services may be applicable in some bands and not in others (e.g. HF vs SHF); services which are expected to be phasing out due to the use of old technology, and emerging services could be identified so as to facilitate a process of using broadly defined services; in considering whether broadly def
15、ined services should be used as opposed to subset services, the concerns of developing countries, such as access to the spectrum and orbit, should be addressed; where broadly defined services are allocated, sharing criteria, conditions to address the exclusive worldwide or regional use of certain ba
16、nds, etc. will be necessary. In studying the use of broadly defined services, a number of factors should be considered. These include at least the economical, social, political, technical and operational factors. In this Recommendation, technical and operational criteria or principles are outlined.
17、3 Technical factors The technical factors which have a major impact on the viability of utilizing broadly defined radio services are: - RF radiated power, - necessary or permitted bandwidth, - interference protection characteristics, - service range or coverage, - coordination factors, - introductio
18、n of new technology (e.g. digital modulation and digital signal structure). 3.1 RF radiated power Generally, different radio services require different RF radiated power levels in order to provide the quality and level of service required. Using radio services which are incompatible in transmission
19、power requirements will introduce severe limitations upon the service with the lower power requirements. 3.2 Necessary bandwidth The bandwidth requirement of a particular radio service depends upon the type of information to be carried and the modulation technique employed. Generally, different radi
20、o services require different transmission bandwidths. If subset radio services which use widely different bandwidths are used together, spill-over and wideband noise from wideband transmissions would cause inter-service interference to narrow-band services unless these were separated by 10 ITU-R REC
21、MN*SM* SERIES 95 D 48552112 0526735 083 Rec. ITU-R SM. 1133 the same guardband as normally applicable to the wideband service. The introduction of such large guardbands to the narrow-band service would tend to reduce the efficiency of spectrum usage, and severely reduce the possible benefits of usin
22、g the broadly defined service. 3.3 Interference protection The protection ratio may be expressed as the ratio of the required signal power to all interference power. The level of interference tolerance for a particular radio service is dependant upon the level or performance requirements provided or
23、 required by that service. The level of protection required by one type of service, may not be suitable for another type of service. Using a broadly defined service where its subset radio services have widely different protection ratios may result in a degradation of performance requirements. 3.4 Ra
24、dio service range or coverage Transmitter RF power, characteristics of electromagnetic wave propagation, frequency of operation and other system factors determine the range or coverage of a radio service. The coverage requirement has a significant possessive bearing upon the frequency band that is u
25、sed to provide that coverage. Homogeneity of subset services ranges or coverage types should be a major consideration to ensure spectrum usage efficiency of the broader service. The broadly defined service should not be used where operations of subset services have widely differing ranges of coverag
26、e. 3.5 Coordination factors Radio services are evaluated, with respect to their harmonious operation with other services operating in the same, similar or dissimilar frequency bands. Ideally, system performance and service types should be of a similar nature to simplify and smooth the coordination p
27、rocess. It is very necessary that coordination be equitable or at least similar between bordering nations, to ensure improved spectrum usage. Using more broadly defined services may in some situations increase the complexity of sharing and coordination and result in a lower spectrum efficiency. If a
28、s a result of using a broadly defined service, the permissible level of interference is exceeded for any of the subset services or excessive reuse distances result, then such a change would not be technically advisable. 3.6 Introduction of new technology The advance of technology in the area of digi
29、tization brings digital signals from various services together resulting in similar technical characteristics. One strategy that could be adopted is to introduce using more broadly defined services in a natural and progressive manner. Furthermore, services (such as land mobile, mobile satellite, etc
30、. which are related to personal communications) also tend to converge. This opens up a new possibility of using broadly defined services in the future. 4 Operational factors The operational factors that are considered to exert the most significant influence are: - type of service, - nature of servic
31、e, - - performance requirements, - priority of service. coverage and service area requirements, ITU-R RECMN*SM. SERIES 95 E 4855212 0526736 TLT E Rec. ITU-R SM. 1133 11 4.1 Type of service Existing radio services may be grouped under the following general headings according to the types of service:
32、- land (fixed, broadcast, mobile, etc.), - maritime (navigation, mobile, etc.), - - - aeronautical (navigation, radiolocation, mobile, etc.), satellite (fixed, mobile, broadcast, navigation, etc.), specialized (radioastronomy, amateur, scientific, standard time signals, etc.). The operational aspect
33、s of service types are dependent to a large extent upon other operationally related factors that include the nature and amount of information or trafic to be carried by the service, the distance or area over which it is required to provide service and the performance requirements expected or require
34、d. The combined effect of these factors tends to create a uniqueness for many service types. Because of this uniqueness, it could require certain service types to be used on the basis of individual narrowly defined subset services. 4.2 Nature of service From an operational point of view, the nature
35、of a radio service can be defined in terms of the characteristics that describe the intent of the service, and includes user aspects. Within the context of the definition, a use and user general grouping might include the following: - private, - public, - broadcast, - aeronautical, - maritime, - tra
36、nsportation. 4.3 The operational coverage requirements of radio services can and do differ considerably, depending upon the particular service employed. However these aspects are dealt with in $3 under the considerations on technical factors. Coverage and service area requirements 4.4 Performance re
37、quirements Ideally, the performance requirements for subset services within a broadly defined service are compatible, or at least similar. 4.5 Priority of service The priority status of radio services can be arranged in almost any manner, depending upon a particular point of view. Priority status ra
38、nks respective services in terms of the importance of their operational requirements or the importance of the use of the service. An example of a proposed and particular ranking of priority for services might be represented as follows: safety services, essential services, governmental services, mili
39、tary services, common carrier services, restricted common carrier services, end-user services, broadcast services, and research services. As a further breakdown, and within the ranking of safety services, there might be included, for example, life, rescue and health services, etc. and within essenti
40、al services police, fire, utilities such as electricity and gas, etc. 5 In the previous sections, the factors which must be considered in using a broadly defined service are discussed. In Fig. 2 a flow-chart guide is provided to a process that can be used in developing a list of merged services. It
41、should be recognized that subjective judgement must be exercised in determining the “Yes” or “No” answer. Process of utilizing broadly defined services 12 ITU-R RECMN*SM- SERIES 75 = 4855212 0526737 956 Rec. ITU-R SM. 1133 FIGURE 2 Guide io utilizing broadly defined radio services Select subset serv
42、ices I Use of broadly defined service not leveihervice area suitable without review/ compatible? introduction of further restraints I No No I 4 c I I I Yes 1 overcome technically? , No No be achieved by other c - - i c Yes A Does nature of service impose special conditions? I service suitable The “b
43、ox” containing the “using a broadly defined service not recommended without reviewhntroduction of further restraints” is intended to indicate that the process should be iterative. If, after first examination, a more broadly defined service is not suitable, then the situation should be reviewed to es
44、tablish if it could be achieved by the imposition of some technical constraints which would not impact on the operational effectiveness of subset services. ITU-R RECMN*SM. SERIES 95 4855212 052b738 892 Rec. ITU-R SM. 1133 13 To determine the ability to use a broadly defined service in a given freque
45、ncy band, it will be necessary, when using the flow-chart, to compare specific quantitative values to assess similarity or compatibility. The discussion above notes that many radio services are not grouped into broadly defined and narrowly defined or subset services. This fact necessarily limits the
46、 application of this concept. Further study is needed to determine whether some or ail of the remaining services can be related to one or more broadly defined services. New services and service definitions may be required. 6 Special considerations on satellite services Certain satellite services are
47、 not suitable at present for using within a broadly defined service, based on the technical characteristics given in the RR and IT-R Recommendations. However, technical and technological changes may reduce the incompatibility of these services and may lead to their convergence even in the near futur
48、e, as can be seen in the case of a general-satellite service (GSS) discussed below. 6.1 Examples - issues concerning the merging of satellite services 6.1.1 Present difficulties in the merger of FSS, BSS and MSS A technical study concerning the effect of a merger between FSS and BSS, FSS and MSS or
49、all three together into one broadly defined service indicates that this could result in a significant reduction in orbit/spectrum utilization efficiency, based on the present technical characteristics of the three services. 6.1.2 Merger of FSS and BSS In general, the FSS is used to provide large capacity, high quality and high availability links. Most such systems employ moderate to large size earth station antennas. Even though small and very small earth station antennas are being introduced for specific applications, their use is accompanied by s
