1、Rep. ITU-R B0.2007-1 1 REPORT ITU-R B0.2007-1 CONSIDERATIONS FOR THE INTRODUCTION OF BROADCASTING SATELLITE SERVICE HIGH DEFINITION TELEVISION SYSTEMS* (1995-1998) 1 Introduction The World Administrative Radio Conference for Dealing with Frequency Allocations in Certain Parts of the Spectrum (Malaga
2、-Torremolinos, 1992) (WARC-92) made an allocation in the bands 21.4-22.0 GHz in Regions 1 and 3 and 17.3-17.8 GHz in Region 2 to the broadcasting-satellite service (BSS) on a primary basis from 1 April 2007. It has adopted, by Resolution 525 (WARC-92), a set of interim procedures to allow BSS high-d
3、efinition television (HDTV) to be introduced in Regions 1 and 3 from 1 April 1992. Resolution 525 (WARC-92) also stipulates that the located frequency band shall be used for HDTV in the BSS. It stipulates further that, before a future conference has taken decisions on definitive procedures, the use
4、of the allocated band shall be based on Resolution 33 (Rev.WRC-97) and Article S27/34 of the Radio Regulations (RR), and that after 1 April 2007 the introduction of HDTV systems in this band must be regulated in a flexible and equitable manner until such time as a future competent world radio confer
5、ence has adopted definitive provisions for this purpose in accordance with Resolution 507. The interim procedures utilize sections of Resolution 33 (Rev.WRC-97) which apply to the BSS in bands where plans are not in force but limits the requirements for coordination with the assignments of other cou
6、ntries to systems which exceed certain trigger values. This Report lists a number of characteristics to be considered in the development of BSS (HDTV) systems under these procedures. Although the interim procedures of Resolution 525 (WARC-92) apply only to the introduction of BSS (HDTV) in the 21.4-
7、22 GHz band in Regions 1 and 3, the material in Q 5,6 and 7, and in the Annexes to this Report may also be of interest for system planning in the 17.3-17.8 GHz band in Region 2. Likewise, this material may be of interest in connection with the possible accommodation in the 12 GHz band of BSS (HDTV)
8、systems, particularly for the tropical countries of Regions 1 and 3 as envisioned in Resolution 524 (WARC-92). 2 Regulatory provisions Resolution 525 (WARC-92) established an interim set of regulatory provisions to give flexible and equitable access to the geostationary orbit and the designated spec
9、trum before a competent radiocommunication conference takes definitive decisions on a replacement procedure. The Resolution makes a distinction between “operational” and “experimental” systems and to systems introduced before and after 1 April 2007. Table 1 indicates the applicable procedures. 3 Sta
10、tus of existing services The band 21.4-22.0 GHz is also allocated to the fixed and mobile services on a primary basis. Paragraph 1 of the Annex to Resolution 525 (WARC-92) indicates that: “It shall be understood that prior to 1 April 2007 all existing services in the band 21.4-22.0 GHz in Regions 1
11、and 3 operating in accordance with the Table of Frequency Allocation shall be entitled to continue to operate. After that date they may continue to operate, but they shall neither cause harmful interference to BSS (HDTV) systems nor be entitled to claim protection from such systems.” This requiremen
12、t may result in fixed services needing to be relocated from the 21.4-22.0 GHz band to other nearby bands. Radiocommunication Joint Working Party (JWP)lO-llS has requested Study Group 9 to look into this topic. * This Report provides technical information relevant to the application of the interim pr
13、ocedures contained in Resolution 525 (WARC-92). 2 Rep. ITU-R B0.2007-1 TABLE 1 General scheme of applicable procedures to implement BSS (HDTV) systems* Date of use of HDTV band Before 1 April 2007 After 1 April 2007 Conditions Experimental systems Operational systems PFD a PFD a New procedures adopt
14、ed by future WRC No new procedures adopted Applicable RR provisions Article S27/34: Experimental stations Res. 33 (Rev.WRC-97), Sect. A: Coordination procedure between space stations in the broadcasting-satellite service and terrestrial stations Res. 33 (Rev.WRC-97), Sect. B: Coordination procedure
15、between space stations in the broadcasting-satellite service and space systems of other administrations Res. 33 (Rev.WRC-97), Sect. C: Notification, examination and recording in the Master Register Res. 33 (Rev.WRC-97), Sect. A: Coordination procedure between space stations in the broadcasting-satel
16、lite service and terrestrial stations Res. 33 (Rev.WRC-97), Sect. B: Coordination procedure between space stations in the broadcasting-satellite service and space systems of other administrations Res. 33 (Rev.WRC-97), Sect. C: Notification, examination and recording in the Master Register Res. 33 (R
17、ev.WRC-97), Sect. B: Coordination procedure between space stations in the broadcasting-satellite service and space systems of other administrations Res. 33 (Rev.WRC-97), Sect. C: Notification, examination and recording in the Master Register Application of such a new procedure Res. 33 (Rev.WRC-97),
18、Sect. B: Coordination procedure between space stations in the broadcasting-satellite service and space systems of other administrations Res. 33 (Rev.WRC-97), Sect. C: Notification, examination and recording in the Master Register * Source: resolution 525 (WARC-92). a: PFD: power flux density limits
19、defined in 3 4 of this Report. 4 Trigger points for coordination The trigger points of power flux-density at the Earths surface produced by emissions from a space station on the territory of any other country are: - - - -115 dEi(W/m2) in any 1 MHz band for angles of arrival between O“ and 5“ above t
20、he horizontal plane or -105 dEi(W/m2) in any 1 MHz bind for angles of arrival between 25“ and 90“ above the horizontal plane or values to be derived by linear interpolation between these limits for angles of arrival between 5“ and 25“ above the horizontal plane. Radiocommunication JWP 10-11s reviewe
21、d these values which are to provide protection to the fixed service and apply only until 1 April 2007, in accordance with Resolution 525 (WARC-92). Beyond this date, higher power flux-density (pfd) levels may be introduced, subject to further studies on service availability requirements. Rep. ITU-R
22、B0.2007-1 3 5 Service requirements Further study is needed on the detailed development of service requirements for BSS HDTV. A set of provisional requirements is listed below: Overall system objectives An agreed standard for satellite broadcasting of digital HDTV (see also Q 9). The transmission sta
23、ndard should be applicable to other relevant media with the minimum conversion complexity. The emitted signal shall be received by small (45-90 cm) individual antenna installation. It should also be suitable to feed cable bead-ends. Compatibility with B-ISDN (broadband-integrated services digital ne
24、twork) is desired. Service and coverage requirements HDTV is intended for fixed reception with highest quality possible within HDTV format (virtual studio quality). Service availability for a percentage of the time of the worst-month (service continuity for digital systems is normally determined by
25、the drop-out point) to be determined by further study (see also Q 6). Subjectively acceptable failure characteristics. In the 21 GHz range, this might require attenuation mitigation techniques such as layered modulation and channel coding as well as adaptive satellite e.i.r.p. control, providing sta
26、ndard definition TV (SDTV) and/or limited definition TV (LDTV) quality only in case of deep fadings. Important note - Sound should not fail before the picture. The choice of a technically suitable modulation technique to achieve (to the extent possible) high spectrum- efficiency, low transmit power
27、and low protection ratios in order to maximize frequency reuse and minimize sharing constraints with the same and other services. Possibility for national, multinational and subnational coverage. Provisions for scrambling with the aim of spectrum shaping for energy dispersal. Provisions for conditio
28、nal access. 5.3 Multiplex-related requirements a) All service elements related to one complete programme service have to be combined using adequate multiplexing techniques. Service elements will include sound, picture and data and, optionally, baseband error protection. b) Fixed gross bit rate at th
29、e output of the multiplexer. c) Flexible multiplex configuration with dynamic reconfiguration. (This includes frequent transmission of multiplex configuration information.) d) Common multiplex and service information (SI) for the various delivery systems. 5.4 Receiver requirements a) User friendline
30、ss. b) c) Acceptable receiver cost in mass production. Maximum of commonality in signal processing for different delivery media, such as satellite, terrestrial and cable transmission. Capability of receiving full quality digital HDTV signals delivered by satellite, terrestrial and cable networks (op
31、tionally in combination with existing TV signals). d) 4 Rep. ITU-R B0.2007-1 6 Service availability The availability of the BSS (HDTV) needs to be given urgent further study. Some Administrations are proposing 99.6% to 99.7% of the worst-month for service continuity. It is noted that since the HDTV
32、system will probably be digital, the system will experience rapid degradation and not the gradual degradation experienced in dialogue systems. Careful selection of the coding and modulation may improve the service availability. Annex 1 and the Annex 3 give possible approaches to this topic. Studies
33、have been performed by Italy on advanced error protection strategies for digital TV/HDTV satellite provisioning. These strategies make use of an “inner” convolutional/trellis code associated with the digital modem and an “outer” block code associated to the video codec to minimize the bit error rati
34、o PER). In receivers operating at high bit rates the use of “parallel Viterbi“ chips may be necessary and this can cause a coding gain degradation. Italy is studying (Doc. lO-llS/97 and Task Group (TG) 11/2) techniques to avoid this degradation. Adaptive satellite e.i.r.p. control using multi-beam s
35、atellite antenna can provide another useful means to improve service availability especially for countries which have high density rainfalls. Annex 2 gives a concept of this approach. It is expected that BSS (HDTV) at 17 and 21 GHz has to cope with large attenuation in most countries. Service availa
36、bility criteria should be discussed in the context of expected attenuation values and corresponding mitigation strategies. Further study is needed on the topic of service availability and new mitigation technologies. 7 Scenarios for a future usage of the 21 GHz band As mentioned in the introduction,
37、 the allocation of the 21 GHz band to BSS has only recently been made at WARC-92. As a consequence of this fact it is difficult at the present time to present consolidated scenarios for the future usage of this band, also taking into account that the allocation of the band will only be fully effecti
38、ve by April 2007. Both Europe and Japan are now working on various research projects (e.g. HD-SAT in Europe) to overcome the technical challenges of exploiting the 21 GHz band in order to prepare for operation of studio-quality (wide-RF band) HDTV and integrated services digital broadcasting (ISDB)
39、BSS in this band. A main goal of the HD-SAT project is to respond to the service requirements set forth in Q 5 of this Report. In June 1995, the HD-SAT project demonstrated to the public digital high-quality HDTV live over a 30/20 GHz satellite link. Both, sound and picture were MPEG-2 coded and dec
40、oded in real-time. Graceful degradation was achieved and demonstrated applying a two-layer modulation concept carrying the HDTV and SDTV versions of the same programme. Interlinking with cable distribution and terrestrial emission of HDTV was also part of the live presentation. The convincing demons
41、tration proved in principle the technical feasibility of a 30/20 GHz studio-quality digital HDTV broadcasting satellite service (see Annex 3). In addition, a satellite mission scenario for Europe was studied, concluding that a central European coverage would be possible with some 55 dBW of e.i.r.p.
42、(see Annex 5). Japan plans to launch in 1997 an experimental satellite COMETS (communication and broadcasting engineering test satellite), including a 21 GHz band mission, to develop new broadcasting systems including ISDB. The bandwidth of the COMETS 21 GHz transponders will be 120 MHz (maximum). T
43、he output power will be 200 W and the number of beams will be 2 (assumed to cover the whole of Japan by 6 beams). New high-data rate broadcasting services supporting ultra high-definition TV and three-dimensional representation are also a long-term development goal in Japan. The ITU-R has establishe
44、d a comprehensive Report on HDTV satellite broadcasting in this band (Report ITU-R B0.1075) and is working on flexible planning concepts for this service. After the completion of the RACE HD-SAT Project, which includes studies by the RAI on possible spectrum management strategies, first results are
45、now available. These are presented in detail in Annex 4. Main parameters will be the maximum permissible pfd and the maximum acceptable interference level expressed in terms of link budget reduction. Rep. ITU-R B0.2007-1 5 While in the near future Europe will introduce digital multi-programme satell
46、ite TV (?multivision?), digital HDTV is a longer term concept, which may require an early access to the 21 GHz frequency band only if studio-like picture quality is anticipated. In any case the new band may not only help to ensure the future of satellite broadcasting but also that of the consumer te
47、levision industry. As a conclusion, it presently seems too early to evaluate the use and the regulatory matters of this band. The completion of further projects now under way, notably COMETS project, will certainly help in refining the scenarios for the usage and planning of the 21 GHz band. 8 Stand
48、ardization process It is necessary to define the service and the associated key parameters in order to obtain the maximum efficiency when using the new frequency allocation. It is known that the GSO is a limited resource. It is also known that the best way to obtain the maximum efficiency in the use
49、 of the orbit-spectrum resource is by proper implementation of the systems with a certain level of uniformity in their key parameters. The implementation of wideband HDTV systems will be promoted when service objectives have been agreed by broadcast organizations, major BSS operators and industry. To do that, it will be necessary to assess all the items that contribute to a complete characterization of the BSS (HDTV) systems such as: Service objectives: - service quality, - service reliability. System characteristics: - propagation factors, - - modulation and channel coding, - receiving syst
