1、 Recommendation ITU-R F.1891(05/2011)Technical and operational characteristicsof gateway links in the fixed serviceusing high altitude platform stationsin the band 5 850-7 075 MHz to beused in sharing studiesF SeriesFixed serviceii Rec. ITU-R F.1891 Foreword The role of the Radiocommunication Sector
2、 is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy fu
3、nctions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC re
4、ferenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and th
5、e ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting
6、 service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellit
7、e and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Genev
8、a, 2011 ITU 2011 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R F.1891 1 RECOMMENDATION ITU-R F.1891*Technical and operational characteristics of gateway links in the fixed service using high altitude platfor
9、m stations in the band 5 850-7 075 MHz to be used in sharing studies (2011) Scope This Recommendation provides the technical and operational characteristics of high altitude platform stations (HAPS) gateway links in the fixed service (FS) in the band 5 850-7 075 MHz. It is intended to provide admini
10、strations with information on HAPS gateway links for use in sharing studies with conventional types of FS systems and with systems and networks of other services in the band above and in adjacent bands. Information on the relationship between gateway links and user links can also be found in this te
11、xt. The ITU Radiocommunication Assembly, considering a) that WRC-07 recognized that it would be desirable to have greater flexibility in the choice of spectrum for gateway operations in support of HAPS networks; b) that WRC-07 requested the studies to consider identification of spectrum for HAPS gat
12、eway links in the range 5 850-7 075 MHz; c) that HAPS gateway links could be used to support operations in the fixed and mobile services; d) that HAPS gateway links in this band would need to share with systems operating in the fixed, mobile, and fixed-satellite services and may have an impact on pa
13、ssive services such as the Earth exploration-satellite service (EESS) and radio astronomy; e) that gateway links in a HAPS system would be limited in number and would need to employ higher performance antennas and higher transmitted power in comparison with user links, which would permit the use of
14、higher order modulation methods and more complex coding; f) that based on considering e), HAPS gateway links would be more spectrally efficient than the user links; g) that technical and operational characteristics of HAPS gateway links in the FS are required in order to perform studies of sharing w
15、ith other types of FS system and with systems and networks of other services in the 5 850-7 075 MHz band, as well as to take into account the out-of-band emissions to or from services in nearby or adjacent bands, recognizing a) that Resolution 734 (Rev.WRC-07) considered that it is desirable to have
16、 adequate provision for gateway links to serve HAPS operations; *This Recommendation has been prepared in support of World Radiocommunication Conference 2012 (WRC-12) Agenda item 1.20. In the event that WRC-12 does not identify spectrum for gateway links for high altitude platform stations in this b
17、and, the Recommendation will be suppressed. 2 Rec. ITU-R F.1891 b) that Resolution 734 (Rev.WRC-07) also resolved to invite ITU-R to extend sharing studies, with a view to identifying two channels of 80 MHz each for gateway links for HAPS in the range from 5 850-7 075 MHz, in bands already allocated
18、 to the fixed service, while ensuring the protection of existing services, recommends 1 that the technical and operational characteristics of HAPS gateway links as contained in Annex 1 to this Recommendation should be used in analysing the feasibility of sharing involving HAPS gateway links in the f
19、requency range from 5 850-7 075 MHz. Annex 1 Technical and operational characteristics of gateway links for high altitude platform stations in the fixed service operating in the 5 850-7 075 MHz band 1 Introduction The technical and operational characteristics of the HAPS system described herein are
20、based on a realizable generic design of the HAPS payload, stratospheric platform and network. 2 HAPS platform stability HAPS obtains its movement stability, relative to the Earth, by controlled flight in the low-density, steady flowing, low-velocity and non-turbulent air stream that exists at partic
21、ular stratospheric altitudes. HAPS operates at a nominally fixed location in the stratosphere at a height of 20 to 25 km. The relatively smooth flowing air stream combined with state-of-the-art propulsion, aerodynamic, thermodynamic and material design will provide a stable and controlled flight tha
22、t will result in accurate position maintenance and minimal axial (pitch, roll, yaw) rotation. The rate of change of the velocity of stratospheric winds is well within the capability of the propulsion and control systems of the platform to maintain the desired position and heading. The same levels of
23、 stability, altitude and position maintenance can be achieved by the heavier-than-air (HTA) and lighter-than-air (LTA) platforms. Typically HAPS will maintain its position to well within 0.5 km, will have less than 1/2/h change in heading, will have changes of altitude less than 45 m/h and will have
24、 virtually no axial rotation. In addition, the application of electronically steerable beam-forming antennas on the HAPS and at its ground stations will further add to the directivity, selectivity and effectiveness of the gateway links and easily neutralize any minimal platform movement. 3 HAPS netw
25、ork architecture HAPS have the capability of carrying a large variety of wireless communication payloads that can deliver high-capacity broadband services to end users. The high-level HAPS telecommunication network architecture is shown in Fig. 1, and described in more detail in this, and other, sec
26、tions that follow. There are two types of links between the payload and the ground equipment: gateway links and user links. This text only describes the technical and operational characteristics of the HAPS gateway links which are proposed to operate in the 5 850-7 075 MHz band. Rec. ITU-R F.1891 3
27、FIGURE 1 HAPS network configuration including gateway links and user links HAPS gateway linksHAPS user linksHAPS platform withcommunicationspayloadRACCPESACCPECPEUACCPEHAPS networkInterfaceInterfaceGateway stationGateway stationTerrestrial network ACorenetworkBase stationcontrollerTerrestrial networ
28、k BPSTN/PSDN/WWWFor the user links, the communication is between the platform and customer premises equipment (CPE) on the ground in a cellular arrangement permitting substantial frequency reuse. The CPE is described as being within one of three zones: urban, suburban and rural area coverage (UAC, S
29、AC and RAC, respectively)1. HAPS CPE may communicate with the payload on the HAPS platform directly and communications between HAPS CPE is switched by the payload containing a large switch through the user links. The transmitted signal from a HAPS CPE is transferred into the receiving section of pay
30、load in the HAPS platform. The on-board switch in the payload determines the cell to link the signal. Then, it is transferred to the cell in which other HAPS CPE to be connected exists. It is emphasized that the user links utilize frequency spectrum outside of the 5 850-7 075 MHz band in accordance
31、with the relevant provisions of the RR. For the gateway links, communication is established in the 5 850-7 075 MHz band between the platform and gateway stations on the ground, located in the UAC, which provide interconnection with other telecommunication networks. The HAPS telecommunication payload
32、 architecture consists of six basic subsystems as depicted in Fig. 2. 1See Recommendation ITU-R F.1500 for a more detailed description of these coverage areas. 4 Rec. ITU-R F.1891 FIGURE 2 HAPS telecommunication network architecture Antennasystem(user links)ServiceXcvrs Switch RouterGatewayXcvrsAnte
33、nnasystem(Gatewaylinks)HAPS Telecommunications payloadCPECustomer premise equipmentGSHAPS Gateway ground stationsHAPScorenetwork Ground network infrastructure2521NCPE CPE1GS GSOthertelecommnetworks Gatewaybackhaulsub-network The central switching and routing subsystems connect the gateway transceive
34、rs and antennas to the service delivery portion of the payload (antennas and transceivers). The service delivery subsystems contain the direct user links (HAPS-CPE) which are completely separate and different from the HAPS gateway links. Network management, telecommunication network connectivity, an
35、d other core network functions are contained in the ground infrastructure portion of the network. A backhaul terrestrial sub-network will also be required to control, integrate and provide a terrestrial concentration and connection for all of the gateway links to the core network. Each of the five g
36、ateway stations will need a baseline fibre optic data link to the core network on the order of 1 Gbit/s per GS. The HAPS gateway station network topology is described in Figs 1, 2 and 3. 4 HAPS gateway link description and use As applied in this document, a HAPS gateway link is defined2as a one-way
37、radio link between a relatively fixed HAPS platform and a HAPS gateway station. Specifically, the HAPS gateway link consists of a separate 80 MHz (ground-to-air) uplink and a separate 80 MHz (air-to-ground) downlink. Within each 80 MHz bandwidth, a HAPS gateway link operates unidirectionally and con
38、tains information flows, such as aggregated end-user traffic for voice, data and video communications. Telemetry, tracking, command and control information related to the operation of the HAPS vehicle itself can also be contained in the HAPS gateway link. Each 80 MHz HAPS gateway bandwidth, may be d
39、ivided into a number of subchannels, with all subchannels supporting 2In the scope of this Recommendation, the “HAPS gateway link” is a radio link from a HAPS ground-based gateway station at a given location to a HAPS platform, or vice versa, conveying information for a HAPS communication link inclu
40、ding telemetry and telecommand, and providing interconnection with other ground telecommunication networks. Rec. ITU-R F.1891 5 radio links in the same (air-to-ground or ground-to-air) direction using any polarization, modulation and coding methods. A single HAPS platform will use a maximum of five
41、gateway station links to support the maximum projected traffic load for that entire single platform. The number of gateway links deployed for each HAPS depends on the amount of end-user application traffic the HAPS-based network or system must support on a backhaul basis. As the actual traffic incre
42、ases, more same-frequency gateway links can be deployed (up to a maximum of five, as needed). Figure 3 illustrates a maximum ground configuration of five same-frequency gateway links that reuse the 2 80 MHz frequency spectrum identified for HAPS use, and this configuration should be used in sharing
43、studies. HAPS platforms would be on the order of about 300 km to 1 000 km apart. Each associated gateway station serves a single HAPS. Typically, the gateway station grid would not overlap with an adjacent HAPS gateway station grid. The gateway grid will likely be within an approximately 72 km diame
44、ter circle centred close to the nadir ground point of the HAPS as illustrated in Fig. 3. As shown in this HAPS gateway station (GS) configuration, the elevation angle referenced to the HAPS nadir is 30 for the UAC zone shown. is the angle at the wanted gateway station between the HAPS platform and i
45、nterfering gateway station. is the angle at interfering gateway station, between the HAPS platform and the wanted gateway station. Angles and are 59.4 or 34.6, depending on the particular gateway station pairs and their associated geometry. , which is the angle at the HAPS between the wanted HAPS ga
46、teway station for that link and a particular interfering HAPS gateway station, is 61 or 111. is the angle at the ground nadir point between any two gateway stations. Table 1 is a summary of the four angles (, , , ) for all the various combinations of gateway station pairs. Table 2 is a summary of th
47、e five possible angles for . FIGURE 3 Example of HAPS gateway station configuration and internal HAPS network interference 2Not to scale. Look anglesare considerably distorted.wantedsignalInterferingsignal21 kmHAPSNadir436 kmradius5InterferingsignalUAC zoneHAPS-GS316 Rec. ITU-R F.1891 It should be e
48、mphasized that Fig. 3 is not to scale. TABLE 1 HAPS gateway link angles (degrees) Station pairs(1) 30 61 59.4 59.4 1-2, 2-1, 2-3, 3-2, 3-4, 4-3, 4-5, 5-4, 1-5, 5-1 30 111 34.6 34.6 1-3, 3-1, 2-4, 4-2, 3-5, 5-3, 1-4, 4-1, 2-5, 5-2 (1)Station pairs X-Y where X is the wanted station and Y is the interf
49、ering station. TABLE 2 Ground station separation angles (degrees) Station pairs 0 1-1 72 1-2144 1-3 216 1-4288 1-5 5 Spectrum identification and channelization The spectrum identification for the HAPS gateway links is expected to be two 80 MHz channels in the 5 850-7 075 MHz band3for a total of 160 MHz. The subchannelization plan can be used to divide each 80 MHz channel into six equally spaced 11 MHz subchannels separated by 2 MHz guardbands as shown in Fig. 4. Other subchannelization frequency plans could possibly4be utilized but the channelization
