1、 Rec. ITU-R M.1653 1 RECOMMENDATION ITU-R M.1653*,*Operational and deployment requirements for wireless access systems including radio local area networks in the mobile service to facilitate sharing between these systems and systems in the Earth exploration-satellite service (active) and the space r
2、esearch service (active) in the band 5 470-5 570 MHz within the 5 460-5 725 MHz range (Questions ITU-R 218/7, ITU-R 212/8 and ITU-R 142/9) (2003) The ITU Radiocommunication Assembly, recognizing a) that additional spectrum for the Earth exploration-satellite service (EESS) (active) and space researc
3、h service (SRS) (active) in the 5 GHz frequency range would support new applications (e.g. wideband sensors); b) that harmonized frequencies in the 5 GHz frequency range for the mobile service would facilitate the introduction of wireless access systems (WASs) including radio local area networks (RL
4、ANs); c) that WAS including RLANs operating in the 5 GHz bands can provide effective solutions to broadband delivery to commercial and residential users; d) that Recommendation ITU-R M.1450 provides a description of WAS including RLANs that are intended to operate in the 5 GHz frequency range; e) th
5、at administrations can approve relevant transmission characteristics of WAS including RLANs required to facilitate sharing with EESS (active) through national equipment approval processes; f) that spreading the loading of WAS across the 5 470-5 725 MHz band would reduce the aggregate emission levels
6、 from WAS into EESS (wideband synthetic aperture radars (SARs) in the band 5 470-5 570 MHz, considering a) that many administrations permit WAS including RLAN devices to operate in the band 5 470-5 725 MHz on a licence-exempt basis as well as in other bands such as 5 150-5 350 MHz and 5 725-5 850 MH
7、z; b) that broadband RLANs could be deployed as licence-exempt devices, consequently making control of their deployment density more difficult; *This Recommendation was jointly developed by Radiocommunication Study Groups 8 and 9, and future revisions should be undertaken jointly. *This Recommendati
8、on should be brought to the attention of Radiocommunication Study Group 7. 2 Rec. ITU-R M.1653 c) that the deployment density of WAS including RLANs will depend on a number of factors including intrasystem interference and by the availability of other competing wireless and wireline access technolog
9、ies and services; d) that there is a need to specify an appropriate e.i.r.p. limit and operational restrictions for WAS including RLANs in the mobile service in this band in order to share with systems in the EESS (active) and the SRS (active); e) that studies conducted by the ITU-R concluded that r
10、adar altimeter operation with a 320 MHz bandwidth centred at 5.41 GHz is compatible with WAS including RLAN characteristics (indoor/outdoor) with an e.i.r.p. of 1 W or less; f) that user terminals will normally be operated while in a stationary position; g) that WAS including RLANs are capable of op
11、erating both indoors and outdoors; h) that interference mitigation techniques such as antenna masks, transmitter power control (TPC), dynamic frequency selection (DFS) and indoor operation are beneficial to sharing between EESS (active) and SRS (active) and WAS including RLANs; j) that aggregate int
12、erference from WAS including RLANs to the EESS (active) and SRS (active) receivers with 320 MHz bandwidth, which could overlap with the 5 470-5 570 MHz band, should be taken into account; k) that the performance and interference criteria of spaceborne active sensors in the EESS (active) are given in
13、 Recommendation ITU-R SA.1166, noting a) that the characteristics of EESS (active) encompass those of SRS (active), recommends 1 that to facilitate sharing with EESS (active) and SRS (active) in the band 5 470-5 570 MHz, as described in Annex 1, either the operational and technical restrictions give
14、n in recommends 2, where WAS is limited to a maximum e.i.r.p. of 1 W, or those given in recommends 3, where WAS is limited to a maximum transmitter power of 250 mW and other WAS configurations with spectral masks versus elevations angle, should be applied to WAS including RLANs; 2 that WAS including
15、 RLANs, operating either indoors or outdoors, in the band 5 470-5 570 MHz as described in Annexes 2 and 3, should: a) be limited to 1 W maximum mean e.i.r.p. and 17 dBm/MHz maximum mean e.i.r.p. spectral density per transmitter (Note 1); b) employ TPC to give an aggregate power reduction of at least
16、 3 dB. If transmitter power control is not implemented, then the power limitation given above should be reduced by 3 dB; c) employ DFS operating across the 5 470-5 725 MHz band designed to provide near uniform loading of the available channels; Rec. ITU-R M.1653 3 NOTE 1 The interference criteria of
17、 spaceborne active sensors in the EESS (active) are provided by Recommendation ITU-R SA.1166. Further studies are required to confirm the suitability of these limitations in recommends 2 to comply with the requirements of Recommendation ITU-R SA.1166. 3 that WAS including RLANs operating either indo
18、ors or outdoors in the band 5 470-5 570 MHz, as described in Annexes 2 and 4, should be subject to the following conditions: a) a maximum transmitter power of 250 mW (24 dBm) or 11 + 10 log B (dBm) per transmitter, whichever power is less (B is the 99% power bandwidth (MHz); b) a maximum e.i.r.p. sh
19、ould not exceed 1 W (0 dBW) or 13 + 10 log B (dBW) per transmitter, whichever power is less; c) the e.i.r.p. spectral density of the emission of a WAS including RLANs base station transmitter operating outdoor in the band 5 470-5 570 MHz should not exceed the following values for the elevation angle
20、 above the local horizontal plane (of the Earth): 13 dB(W/MHz) for 0 45 Annex 1 Methodology and parameters used in sharing studies 1 Technical characteristics of wideband spaceborne active sensors Technical characteristics of wideband spaceborne active sensors in the 5 250-5 570 MHz band are given i
21、n Tables 1 and 2. TABLE 1 5.3 GHz typical wideband spaceborne SAR characteristics Value Parameter SAR2 SAR3 Orbital altitude (km) 600 (circular) 400 (circular) Orbital inclination (degrees) 57 RF centre frequency (MHz) 5 405 Peak radiated power (W) 4 800 1 700 Polarization Horizontal and vertical (H
22、H, HV, VH, VV) Pulse modulation Linear FM chirp Pulse bandwidth (MHz) 310 4 Rec. ITU-R M.1653 TABLE 1 (end) Value Parameter SAR2 SAR3 Receiver bandwidth (MHz) 320 Pulse duration (s) 31 33 Pulse repetition rate (pps) 4 492 1 395 Duty cycle (%) 13.9 5.9 Range compression ratio 9 610 10 230 Antenna typ
23、e (m) Planar phased array 1.8 3.8 Planar phased array 0.7 12.0 Antenna peak gain (dBi) 42.9 42.7/38 (full focus/beamspoiling) Antenna median side-lobe gain (dBi) 5 Antenna orientation (degrees from nadir) 20-38 20-55 Antenna beamwidth (degrees) 1.7 (El), 0.78 (Az) 4.9/18 (El), 0.25 (Az) Antenna pola
24、rization Linear horizontal/vertical System noise temperature (K) 550 Receiver front end 1 dB compression point ref to receiver input (dBW) 62 input Analogue-digital converter (ADC) saturation ref to receiver input 114/54 dBW input 71/11 dB receiver gain Receiver input maximum power handling (dBW) +7
25、 Operating time (%) 30 the orbit Minimum time for imaging (s) 15 Service area Land masses and coastal areas Image swath width (km) 20 16/320 Rec. ITU-R M.1653 5 TABLE 2 5.3 GHz typical wideband spaceborne altimeter characteristics Annex 2 Sharing constraints between wideband radar altimeters and bro
26、adband RLANs in the 5 470-5 570 MHz band Introduction This Annex presents the results of the sharing analyses for the band 5 470-5 570 MHz between the wideband spaceborne radar altimeter and the broadband RLANs. Section 1 contains the results of sharing studies between typical RLAN systems and radio
27、 altimeters. The sharing analysis gives positive conclusions about the sharing feasibility in the 5 470-5 570 MHz band. Jason mission characteristics Lifetime 5 years Altitude (km) 1 347 15 Inclination (degrees) 66 Poseidon 2 altimeter characteristics Signal type Pulsed chirp linear FM Pulse repetit
28、ion frequency (PRF) (Hz) 300 Pulse duration (s) 105.6 Carrier frequency (GHz) 5.410 Bandwidth (MHz) 320 Emission RF peak power (W) 17 Emission RF mean power (W) 0.54 Antenna gain (dBi) 32.2 3 dB aperture (degrees) 3.4 Side-lobe level/maximum (dB) 20 Back side-lobe level/maximum (dB) 40 Beam footprin
29、t at 3 dB (km) 77 Interference threshold 118 dBW in 320 MHz Service area Oceanic and coastal areas 6 Rec. ITU-R M.1653 1 Sharing between RLANs and radar altimeters 1.1 Introduction This section presents the results of a sharing analysis for the band 5 470-5 570 MHz between spaceborne radar altimeter
30、 sensors and broadband RLANs. 1.2 Technical characteristics of the two systems The technical characteristics of the RLANs used for the sharing analysis are those of the HIPERLAN type 2, for which Europe has published the relevant specifications. It provides broadband RLAN communications that are com
31、patible with wired local area networks (LANs) based on ATM and IP standards. HIPERLAN/2 parameters: e.i.r.p.: 0.2 W (in the 5 250-5 350 MHz band) and 1 W (in the 5 470-5 570 MHz band) Channel bandwidth: 16 MHz Channel spacing: 20 MHz Antenna directivity: Omni Minimum useful receiver sensitivity: 68
32、dBm (at 54 Mbit/s) to 85 dBm (at 6 Mbit/s) Receiver noise power (16 MHz): 93 dBm C/I: 8-15 dB Effective range: 30-80 m In addition, it is assumed that the following features are implemented: TPC to ensure a mitigation factor of at least 3 dB; DFS associated with the channel selection mechanism requi
33、red to provide a uniform spread of the loading of the RLAN devices across a minimum of 330 MHz. It is to be noted that the numbers given in the deployment scenarios are based on the assumption of the availability of a total of 330 MHz band for RLANs. Assuming that this bandwidth will be available in
34、 two sub-bands (5 150-5 350 MHz and 130 MHz above 5 470 MHz) and given the channel spacing and the need to create a guardband at the boundaries of the two sub-bands, the assumed number of channels used in the study is 8 in the lower band and 11 in the upper band. For the purpose of the sharing study
35、, the following assumptions related to the RLAN usage also apply: average building attenuation towards EESS instruments: 17 dB; active/passive ratio: 5%; percentage of outdoor usage: 15%. For the spaceborne radar altimeter the characteristics in Annex 1 of this Recommendation are taken. Rec. ITU-R M
36、.1653 7 1.3 Interference from a single RLAN into altimeters For this analysis, we consider one RLAN in the altimeter main lobe. The altimeter has an extended bandwidth of 320 MHz, while the HIPERLANs have a channel bandwidth of 16 MHz included within the altimeter bandwidth. The maximum RLAN transmi
37、tted e.i.r.p. (PhGh) is 30 dBm. The altimeter antenna gain, G0, is 32.2 dB, Gais the off-axis antenna gain towards the RLAN, with additional 1 dB input loss, L. The altimeter is nadir pointing, antenna size is 1.2 m. R is the range of the altimeter from the RLAN. The power received by the altimeter
38、from one RLAN in the boresight of the SAR (i.e. Ga= G0) is: LRGGPPahhr222)4( = (1) Considering the most critical RLAN parameters amongst those given in 1.2 (e.i.r.p. of 1 W, outdoor attenuation which implies no building attenuation and no additional mitigation factor), we obtain a value for Pr= 108.
39、3 dBm. The altimeter interference threshold is 88 dBm; we can thus deduce that the altimeter can withstand the operation of a number of RLANs simultaneously, since we have a 20.3 dB margin. Furthermore, the altimeter is built to provide measurements mainly over oceans and is not able to provide accu
40、rate data when a significant amount of land is in view of its antenna beam. For completeness, the number of HIPERLANs in the 3 dB footprint that can be tolerated by the altimeter operating over land is calculated in the section below. 1.4 Estimation of the number of RLANs in the 3 dB footprint of an
41、 altimeter The approach described below enables to estimate the number of tolerable RLANs in the visibility of an altimeter using the altimeter interference threshold of 88 dBm. A simplistic approach is chosen, which assumes that all RLAN devices are seen from the altimeter in its main beam, i.e. Ga
42、= G0, and that the distance between the altimeter and the RLAN is constant and equal to the minimum distance, which is the altitude of the altimeter. This consists of dividing the margin obtained in the calculation below to derive the allowed number of RLANs applying some factors related to the aggr
43、egation factors. Aggregate building attenuation Since the altimeters are nadir pointing an additional path loss of 20 dB (due to roof and ceiling attenuation) is included when calculating the interference from indoor RLANs. It is assumed that the operation of outdoor RLANs is allowed. As stated in 1
44、.2, it is assumed that 15% of devices are outdoors at a given time, which leads to an aggregate additional attenuation factor of 8 dB. 8 Rec. ITU-R M.1653 Activity factor An activity factor of 5% is considered for the RLANs, which means that 5% of RLANs will be transmitting at once. Transmitter powe
45、r control The e.i.r.p. of the RLAN devices is taken at the maximum level: 1 W with an additional aggregate mitigation factor of 3 dB provided by the TPC over the satellite footprint as described in 1.2. TABLE 3 Calculation of number of terminals in the 3 dB footprint We then obtain a number of 27 54
46、0 RLANs installed in the altimeter footprint as a limit not to interfere into the altimeter. Considering the size of the altimeter footprint (77 km diameter), it corresponds to about 6 RLAN devices/km2. Extra margins remain in the fact that: No polarization loss or additional propagation losses have
47、 been taken into account (about 3 dB). The gain of the altimeter in the direction of RLAN devices was overestimated in the calculation. The distance between the altimeter and the RLAN was underestimated. Furthermore, the altimeter is built to provide measurements mainly over oceans and is not able t
48、o provide accurate data when a significant amount of land is in view of its antenna beam. We can thus conclude that the altimeter will not suffer from interference from HIPERLANs when used over oceans and coastal areas. 1.5 Interference from altimeters into RLANs In this case we consider a bandwidth
49、 reduction factor Bh /Ba, since the altimeter bandwidth Ba is much larger than the HIPERLANs bandwidth Bh. Ba= 320 MHz and Bh= 18 MHz, hence a reduction factor of 12.5 dB is obtained. The RLAN antenna gain Ghtowards the vertical direction is 0 dB. The power received by one RLAN from the altimeter is: ahhaarLBRBGGPP222)4( = (2) Altimeter interference threshold (in 320 MHz) 88 dBm RLAN e.i.r.p. 30 dBm Power received from one RLAN at the altimeter 108.3 dBm Percentage of RLANs operating outdoors 15% Aggregate build
