1、Rec. ITU-R F.1334 1RECOMMENDATION ITU-R F.1334*PROTECTION CRITERIA FOR SYSTEMS IN THE FIXED SERVICE SHARINGTHE SAME FREQUENCY BANDS IN THE 1 TO 3 GHz RANGEWITH THE LAND MOBILE SERVICE(Question ITU-R 133/9)(1997)Rec. ITU-R F.1334The ITU Radiocommunication Assembly,consideringa) that systems in the fi
2、xed service (FS) and land mobile service (LMS) share many frequency bands between1 and 3 GHz;b) that many systems in the FS are operational or are planned for operation in these shared bands, both analogueand digital for point-to-point (P-P) and point-to-multipoint (P-MP) applications;c) that it is
3、necessary to specify the maximum allowable interference into the FS;d) that reasonable geographic separations are necessary to permit sharing of overlapping frequency assignments;e) that geographic separations are necessary in certain cases to permit sharing of orthogonally polarizedassignments;f) t
4、hat the typical receiver thermal noise of systems in the FS as given in Recommendation ITU-R F.758 is of theorder of 140 dB(W/MHz),recommends1 that the protection criteria for the FS sharing frequency bands between 1 and 3 GHz with the LMS beestablished as follows (see Note 1): the maximum aggregate
5、 interference from the LMS including base stations and mobile stations should be such thatthe degradation to a FS receiver threshold does not exceed 1 dB under normal propagation conditions;2 that Annex 1 should be referred to for the additional information relating to the protection of systems in t
6、he FSsharing frequency bands between 1 and 3 GHz with the LMS.NOTE 1 In certain situations of unfavourable propagation conditions, it may become necessary to establish anadditional criterion to avoid excessive degradation to a FS threshold (for example, degradation exceeding 10 dB) for asmall time p
7、ercentage. The level of such degradation and the time percentage should be agreed by the administrationsconcerned.NOTE 2 Further study should be continued to improve this Recommendation in close collaboration with Radiocom-munication Study Group 8 (Working Party 8A). Administrations and other organi
8、zations are requested to submitcontributions to the ITU-R._*This Recommendation should be brought to the attention of Radiocommunication Study Group 3 (Working Parties 3K and 3M)and Radiocommunication Study Group 8 (Working Party 8A and Task Group 8/1).2 Rec. ITU-R F.1334ANNEX 1Considerations for th
9、e protection of the FS sharingfrequency bands between 1 and 3 GHz with the LMS1 IntroductionThe World Administrative Radio Conference for Dealing with Frequency Allocations in Certain Parts of the Spectrum(Malaga-Torremolinos, 1992) (WARC-92) made many amendments and additions to the Table of Freque
10、ncyAllocations. In the case of future public land mobile telecommunication systems (FPLMTS), identification of thebands 1 885-2 025 MHz and 2 110-2 200 MHz was made by way of Footnote 746A (S5.388) of Radio Regulations.These bands are already extensively used by radio-relay systems. Now that WARC-92
11、 decisions are known, sharingstudies of affected services should continue.Resolution 113 (WARC-92) specifically addresses sharing and adjustments to the FS as consequences of changes tofrequency allocations in the range 1-3 GHz.Fixed radio-relay systems operating in the 1-3 GHz band form a vital par
12、t of the telecommunications service of manyadministrations. Thus, the study of spectrum sharing with other services must include due consideration for maintainingthe high availability and performance standards required for telecommunications services.This Annex examines, by way of example, the feasi
13、bility of frequency sharing between point-to-point radio-relaysystems in the FS and systems in the LMS.The approach adopted in this Annex recognizes that: the formulation of sharing guidelines for both the fixed systems and land-mobile systems should reflect thecharacteristics of, and performance ob
14、jectives for the respective systems; a study based on the consideration of several spectrum sharing examples can provide a broader understanding of thetechnical issues involved, and the mutual interference between the FS and land-mobile systems may be meaningfully described on a statisticalbasis, an
15、d consequently by applying a statistical approach to this spectrum sharing question guidelines can beformulated which will properly reflect the performance under sharing. The actual levels of interference may alsoneed to be considered deterministically for each situation.Systems in the mobile servic
16、e (MS) encompass a number of operating environments. They include, for example,personal, mobile and satellite communications. In this Annex, the mobile (R1 interface) segment is concerned with thecommunications services between vehicles and base stations. The personal (R2 interface) segment postulat
17、es the use ofpersonal communications in a pedestrian environment indoors and outdoors. The satellite segment may be concernedwith services such as paging functions, linking remote base stations or providing temporary system extension. Thissharing study is restricted to the R1 and R2 interfaces of sy
18、stems in the LMS.Rec. ITU-R F.1334 32 Characteristics of FS and MS2.1 Fixed systemsExamples of the technical characteristics of some radio-relay systems are given in Table 1.TABLE 1aExample 1-3 GHz digital radio-relay systemsTABLE 1bExample 1-3 GHz P-MP systemsOther characteristics relevant to the o
19、peration of fixed systems include: the nature of the propagation, which is generally characterized by distinct non-fading and fading periods, wherefading occurs as the result of anomalous propagation conditions (often late at night and/or during the early hours ofthe morning) including possible obst
20、ruction effects; the operating flat fade margin, which is typically 30-40 dB; the primary mechanism of errors. For low capacity systems (under 10 Mbit/s) this is signal level fading (rather thandispersive effects), and the performance requirements, which are described in Recommendations ITU-R F.594,
21、 ITU-R F.634, ITU-R F.696,ITU-R F.697, ITU-R F.1092 and ITU-R F.1189.Modulation O-QPSK 64-QAMAntenna gain, GFS(dBi) 33 33Transmit power, PFS(dBW) 7 1e.i.r.p. (dBW) 40 34Noise floor (dBW) 125 130Bandwidth, Bf(MHz) 29 10Maximum I (I/N = 6) (dBW) 131 136O-QPSK: quadrature phase shift keying64-QAM: quad
22、rature amplitude modulation.Parameter Central station OutstationAntenna type Omni/sectoral Dish/hornAntenna gain (dBi) 10/13 20 (analogue)27 (digital)e.i.r.p. (maximum) (dBW): analogue digital12242134Noise figure (dB) 3.5 3.5Feeder loss (dB) 2 2IF bandwidth (MHz) 3.5 3.5Maximum permissible long-term
23、 interferencepower (20% time): total (dBW) (dB(W/4 kHz) (dB(W/MHz)1421701471421701474 Rec. ITU-R F.13342.2 Systems in the LMSThe assumed technical characteristics of the LMS R1 and R2 interfaces are given in Table 2.TABLE 2Sharing parameters in the LMSThe principal special consideration for the FPLM
24、TS is the mobile nature of the personal stations. It is to be expected thatthe operation of personal stations of FPLMTS will be desired almost anywhere. Spectrum sharing by both the FS andFPLMTS should be carefully coordinated. Possible sharing features of FPLMTS include frequency agility that could
25、permit dynamic avoidance of radio channels that could cause interference to the FS, and the use of dynamic powercontrol.Other characteristics relevant to the MS including FPLMTS operation include: the nature of the propagation, notably, that fading occurs as the result of multipath propagation cause
26、d byreflections/refraction off buildings etc. rather than anomalous propagation; the statistical nature of the operating fade margin; the random nature that the MSs positions undertake within the FPLMTS service area, which gives rise to astatistically varying interference environment; the (expected)
27、 time-of-day nature of MS traffic. In particular, that heavy traffic generally occurs during the day(especially during working hours), and very light traffic late at night and during the early hours of the morning, and the performance requirements, which could require satisfactory performance over 9
28、0% of the service area for theR1 interface, and 99% of its service area for the R2 interface.Example 1 Example 2 Example 3 Example 4Interface R2 base/personal R1 R2 R2Access method TDMA FDMA/TDMADuplex method TDD TDDTransmit power (W) 0.02 1 0.12 0.01Antenna gain, Gm(dBi) 0 0 0 0e.i.r.p. (dBW) 17 0
29、9 20Noise floor (dBW) 152 152.5 146.2Channel bandwidth, Bm(kHz) 50 135 576 100Maximum I (10% external I ) (dBW) 149Frequency reuse cluster 16 10-15Interfering mobiles per channel(1), m 1/16 1 5 1/4FDMA: frequency division multiple accessTDMA: time division multiple accessTDD: time division duplex(1)
30、The total number of mobiles, n, interfering with a fixed station is equal to n = m Bf /Bm. The values for m are those assumed inthe calculations in this Recommendation.Rec. ITU-R F.1334 53 Interference scenariosThere are four basic interference paths to consider for the interference analysis. These
31、are:Forward link:a) the FS interferes with the outdoor mobile stations;b) the base station (BS) interferes with the FS.Return link:c) the personal outdoor stations interfere with the FS;d) the FS interferes with the BS.It is generally viewed that co-channel operation by the FS and MS in the same geo
32、graphic area will cause unacceptableinterference to the FS. The following analysis involves development of “sharing objectives” for b) and c) of the aboveinterference paths. These sharing objectives could then be met by geographic and/or frequency separation of MS andfixed systems.4 Sharing objectiv
33、esThe sharing objectives define the conditions under which sharing is deemed to be feasible. To maximize the utilizationefficiency of the spectrum the relevant characteristics of the respective systems need to be considered. It is thennecessary to define the requirement for the wanted-to-interferenc
34、e power ratio and/or the requirement for theinterference-to-noise power ratio, where either/both the wanted and interference powers may involve a statisticaldistribution.For each of the two scenarios which are b) and c) of 3, the following statistical sharing objectives are proposed toestablish gene
35、ral guidelines for sharing, where the values of the parameters A1, A2, X 1 and X 2 are required to reflectthe performance objectives of the respective systems: BS into FS: Allow spectrum sharing for position of the FSs and BSs where:ProbInterference Power*A1 (dBm) Ptm A2 Lfm Lff+ H + k N(10)5.2 Exam
36、ple at 2 GHzThe parameters used in the following examples are taken from Tables 1 and 2 (examples 2 and 3).For mobiles operating over either the R1 or R2 interface, the shadow fading dB spread is taken as 6.0 dB. (Typical forurban and suburban environments.)5.2.1 FPLMTS into fixedThe assumed interfe
37、rence power threshold is that 6 dB below the noise floor.Sharing objective:ProbUmN 113.9 6.0 + 3.0 (dBm) 30.0 (116.9) 3.0 + 9.48 + (4.0 3.80) = 168 dB (12)5.2.3 FPLMTS-R2Based on estimate given above, assume N = 10.0, which gives H = 13.2 dB and N= 2.93 dB. The sharing criteriabecomes:Lt 20.8 (116.9
38、) 3.0 + 13.2 + (4.0 2.93) = 159 dB (13)These examples illustrate a possible approach to the assignment of values to the parameters Ai and Xi, and a method forthe calculation of the sharing criteria. From the fixed and mobile antenna characteristics and suitable propagationmodels, the above calculate
39、d sharing criteria can be translated into the required exclusion distances.Further study is needed to determine generalized values for the parameters Ai and Xi and the resulting isolationrequirements. Both long- and short-term performance objectives need to be considered, as well as determination of
40、 themost representative propagation models for the various interference paths.These propagation studies will be critical to sharing and urgent study of appropriate models by RadiocommunicationStudy Group 3 is requested.8 Rec. ITU-R F.13346 Interference analysisAs a first estimate to the separation d
41、istances required between fixed services and the personal segment service areas ofMS (R2 interface), this section considers the median interference powers between these services when the path lossbetween them is about 130 dB. It is noted that this analysis does not take account of the statistical na
42、ture of theinterference powers about the median level (which was discussed in 5), the distribution of which will impact on theexclusion distances required.For a path loss of 130 dB then:Lt= FSL GFS GM= 130where:FSL : free space lossGFS: FS antenna gainGM :MS antenna gain.MS and other interference so
43、urces should not cause more than 10% degradation to the performance of FS systems. Thiscorresponds to I/N = 6 dB and total interference level of IT= 136 dBW in a 10 MHz wide FS radio receiver. Assum-ing dynamic channel assignment in example 4 of Table 2, up to 25 MS users may dwell around the worst
44、3 dBr point,and the most conservative single exposure interference I1= IT 10 log 25 150 dBW may apply. If a mobile unit =e.i.r.p. 20 dBW (an output power is 10 mW, and antenna gain is 0 dBi), then an isolation of 20 (150) = 130 dB maybe necessary. Since the ray path transmission loss Ltnear the wors
45、t point (i.e. 3.3 km in front of an FS radio antenna andat 3 dBr of the boresight) is 78.5 dB, an additional isolation of 130 78.5 = 51.5 dB is necessary. This may be achievedby an adjacent channel operation. In some cases, e.g. when an MS transmitter operates at the edge of an FS radiochannel, a co
46、-channel operation may apply.At a distance of 3.3 km behind the FS radio antenna, Lt= 78.5 3.0 + 60.0 135.5 dB (the ray path transmission loss atthe 3 dBr of boresight plus the front-to-back ratio of the antenna); here a front-to-back ratio of 60 dB is assumed, whichrelates to an ultra high performa
47、nce antenna type. Since 135.5 130, mobile transmitters wandering 3.3 km away andbehind the FS radio antenna may be able to use the same frequency as the corresponding FS radio receiver. However, ananalysis needs to be extended to the whole FS radio network in the area. The 3.3 km point behind one FS
48、 receiver couldbe near the main beam of the adjacent hop which, in a two-frequency plan would have the same receive channel. Thisimplies that there could be an annular exclusion zone around each FS station with odd-numbered stations receiving onone set of channels (e.g. the go channels) and even-num
49、bered stations receiving on corresponding return set of channels.If a figure eight-shaped exclusion zone (e.g. the 130 dB contour) is applicable, the envelope of all co-frequencyexclusion zones can form a corridor along the FS route in the worst case. However, there exists a strong possibility thatother frequency channels will be available within this area.6.1 Forward link analysisThe parameters used in the following examples are taken from Tables 1 and 2 (example 1).Interferen
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