1、 STD-CEPT ERC REPORT b2-ENGL 3998 111 2326414 0033574 208 H ERC REPORT 62 European Radiocommunications Committee (ERC) within the European Conference of Postal and Telecommunications Administrations (CEPT) COMPATIBILITY ANALYSIS REGARDING POSSIBLE SHARING BETWEEN THE UIC SYSTEM AND RADIO MICROPHONES
2、 IN THE FREQUENCY RANGES 876 - 880 MHz AND 921 - 925 MHz Sifok, May 1998 STDmCEPT ERC REPORT b2-ENGL 1998 232b434 0033575 344 ERC REPORT 62 Copyriglit 1998 the European Conference of Postal and Telecommunications Administrations (CEPT) STD.CEPT ERC REPORT 62-ENGL 1778 2326424 O033576 O80 ERC REPORT
3、62 Compatibility analysis regarding possible sharing between the UIC system and radio microphones in the frequency ranges 876 - 880 MHz and 921 - 925 MHz 1 INTRODUCTION 1 2 SYSTEM PARAMETERS . 1 2.1 UIC SYSTEM PARAMETERS . 1 2.2 SYSTEM PARAMETERS OF RADIO MICROPHONES 2 INTERFERENCE SCENARIO: UIC SYS
4、TEM INTERFERES WITH RADIO MICROPHONES 2 3 3.1 WANTED FIELD STRENGTH FOR RADIO MICROPHONES . . 2 3.2 PROPAGATION MODELS 3 Required decoupling attenuation 4 Required separation distances 4 3.4 INTERPRETATION OF THE RESULTS OF THE ANALYSIS. . 4 UIC mobile station interferes with radio microphones (scen
5、arios I. I - 1.3 and 2. I - 2.3. See Table I) . 5 3.3 RESULTS OF THE COMPATIBILITY ANALYSIS 3.3.1 3.3.2 3.4.1 Use ofthe UIC system . 4 3.4.2 3.4.2.1 Co-channel operation . 3.4.2.2 Operation on adjacent frequenci UIC base station interferes with radio microphones (scenarios 3. I - 3.3 and 4. I - 4.3.
6、 Se 3.4.3 3.4.3.1 Co-channel operation 5 3.4.3.2 Operation on adjacent channels 5 3.5 CONCLUSION . 5 INTERFERENCE SCENARIO: RADIO MICROPHONES INTERFERE WITH UIC SYSTEM 6 4.1 CALCULATIONS . . 6 Scenario I: A radio microphone interfering with a UIC base station receiving a signal from a distant mobile
7、 6 Scenario 2: A radio microphone interfering with a UIC mobile station 8 4.2 CONCLUSIONS . . . 8 4.3 REFERENCES . 8 4 4.1. I 4.1.2 ANNEX 1 ANNEX 2 PROPAGATION MODEL OF COST 231 PROJECT, WALFISH-IKEGAMI-MODEL 9 PROPAGATION MODEL OF ITU-R P. 529-2, HATA-MODEL 1980 13 ANNEX 3 ANNEX 4 CALCULATION OF TH
8、E NECESSARY SEPARATION DISTANCE AND ATTENUATION BETWEEN UIC AND RADIO MICROPHONES . 15 MICROPHONE RECEIVER MASK . 21 STD.CEPT ERC REPORT 62-ENGL 3998 2326434 0033577 TL7 ERC REPORT 62 Compatibility analysis regarding possible sharing between the UIC system and radio microphones in the frequency rang
9、es 876 - 880 MHz and 921 - 925 MHz Summary: A study has been carried out which addresses the potential interference from the UIC system to radio microphone operation, and vice-versa. The main results of the study are: the UIC systems would be likely to cause an unacceptable levei of interference to
10、radio microphone operation. The separation distances needed extend to several kilometres, which combined with the UIC requirement for coverage up to 10 km from railway tracks, would leave little possibility for sharing based on geographic separation in most European countries; radio microphones woul
11、d be likely to cause interference to UIC base stations at a distance of up to 5 km. Again taking account of the proposed coverage of the systems, there is little possibility for sharing based on geographic separation in most European countries. STD*CEPT ERC REPORT b2-ENGL 3998 232b414 0013578 953 ER
12、C REPORT 62 Pase 1 1 INTRODUCTION The purpose of this study is to investigate the possibility of sharing between the UIC System and professional radio microphones in the UIC bands 876 - 880 MHz and 921 - 925 MHz. The UIC system is a radio system, based on the GSM standards, intended mainly for train
13、 control purposes and for the exchange of voice messages overriding train signalling information. However it will also be used for road based applications such as maintenance and buses. The radio microphones considered in this study are professional applications. Therefore the stringent requirements
14、 for broadcast quality are taken into account. Radio microphones are assumed to be operated mainly indoors, although outdoor use is not prohibited. Section 3 of this document considers radio microphones interfered with by the UIC system, whilst section 4 considers the UIC system interfered with by r
15、adio microphones. 2 SYSTEM PARAMETERS 2.1 UIC system parameters 876 - 880 MHz Operation: Mobile (traincarhand-held) transmittters Base station receives Mobile Station: Transmit power MS: Antenna gain: Radiation: omnidirectional Antenna height: 39 dBm (traidcar) 30 dBm (hand-held) 2 dBi (traincar); O
16、 dBi (hand-held) Mounted on train roof: 4 m above rail level (see Note) 1.5 m (carhand-held) Bandwidth: 200 IrHz Base station: Receiver sensitivity: - 104 dBm C/I value: 9 dB 921 - 925 MHz Operation: Base station transmitters Mobile (traincarhand-held) receives Base station: Transmit power BS: Anten
17、na gain: 16 dBi Radiation: omnidirectionalidirectional Antenna height: 20 - 30 m (typically 30 m) Bandwid th : 200 kHz typically 39 dBm max. 45 dBm Mobile Station: Receiver sensitivity: - 102 dBm CI1 value: 9 dB Note: The height ofthe mobile antenna above ground may change greatly from one location
18、to the other because trains in luge cities can be conveyed in d(Jeren1 uuvs: elevated stations, bridges or underground. STDmCEPT ERC REPORT 62-ENGL 1998 W 2326434 0033579 9T ERC REPORT 62 Page 2 2.2 System parameters of radio microphones Transmitter output power hand-held: Transmitter output power b
19、ody worn: Transmitter spectrum mask: Bandwidth (- 60 dB): 1 O dBm 17 dBm in acc. with ETS 300 422 analogue as in ETS 300 422 (max. 200 kHz) digital approx. 300 kHz Receiver input power: analogue - 68 dBd68 dB(pV/m) (in acc. with Chester) digital - 85 dBd51 dB(pV/m); (see section 3.1) C/I ratio: anal
20、ogue: 27 dB (acc. to manufacturer specifications) digital: 18 dB (acc. to manufacturer specifications) Max. interfering field strength: analogue: 41 dB(pV/m) digital: 33 dB(pV/m) Receiver spectrum mask: see Annex 4 Operating modes: indoor and outdoor Channel selection: no dynamic channel selection,
21、frequency tuning possible throughout the frequency range 3 INTERFERENCE SCENARIO: UIC SYSTEM INTERFERES WITH RADIO MICROPHONES 3.1 Wanted field strength for radio microphones In this compatibility analysis three radio microphone scenarios are examined: 1 Use of analogue microphones (operation with m
22、inimum wanted field strength) Minimum wanted field strength 68 dB(pV/m); C/I = 27 dB; coverage radius approx. 150 m = maximum interfering field strength 4 1 dB( pV/m) 2 Use of digital microphones (operation with minimum wanted field strength) Minimum wanted field strength 5 1 dB(pV/m); CA = 18 dB; c
23、overage radius approx. 1 km = maximum interfering field strength 33 dB(pV/m) 3 Use of digital microphones (coverage radius = 150 m) Minimum wanted field strength 68 dB(pV/m); Ch = 18 dB = maximum interfering field strength 50 dB(pV/m) For the above calculation of the coverage radius a bodyloss of 14
24、 dB for bodyworn and 6 dB for handheld equipment was used. Furthermore an antenna gain of O dBd (2 dBi) for the microphone transmitter was taken into account. These parameters are assumed to reflect the practical coverage scenarios. The minimum wanted field strength for a digital receiver with a sen
25、sitivity of - 103 dBm (33 dB(pV/m) and a required C/I of 18 dB was assumed to be 5 1 dB(pV/m). In view of the transmitter powers now specified for hand-held and body worn devices a coverage radius of approximately 1 km would be possible. In this case the maximum permissible interfering field strengt
26、h would be 33 dB(pV/m). However, if the same receiver is assumed but the coverage radius is reduced to 150 m the wanted field strength is 68 dB(pV/m) and the permissible interfering field strength is 50 dB(pV/m). STD-CEPT ERC REPORT b2-ENGL 2998 2326Y24 0013580 502 W ERC REPORT 62 Page 3 3.2 Propaga
27、tion models The compatibility analysis was based on different propagation models: Frequency range (876 - 880 MHz) COST 23 1, Walfish-Ikegami, for medium-sized town and suburban areas (see Annex 1) Frequency range (92 1 - 925 MHz) Free space propagation to determine worst case conditions (rnax. radio
28、 horizon) Equation: Lfrccspace = 32.5 + 20log(d) + 2010g(f) HATA model (suburban area) for distances 2 1 km Equation: a hr 6 , ? = 3.2. (log ( 1 I .75-h ;2 - 4.971 , / rl , r: LHataht,hr,f,d;j -69.55+26.1610g(f)- 13.8210g hti ahrih,f + (44.9- 6.5510gihti ,log(d) 0 Rough approximation of the propagat
29、ion loss at distances between 1 O0 m and 1 km (interpolation of free space propagation on the Hata model) Equation: (f.0 i) LHata( ht, hr,f,i) -Lfree-space I0gM Linterpolate(ht,hr,fd) = (This “model“ has not been verified. It was selected because no other suitable model is available at present for d
30、istances of less than 1 km.) A graphical representation of the entire “model“ is given in Annex 2. Legend: d: distance in km f frequency in MHz L: propagation loss in dB h,: h,: transmitting antenna height in m receiving antenna height in m STD-CEPT ERC REPORT 62-ENGL 1778 2326434 OOL3581 448 ERC RE
31、PORT 62 Page 4 Analogue microphones (operation with min. wanted field strength) 1.1 3.3 Results of the compatibility analysis Digital microphones Digital microphones (operation with min. Wanted (coverage field strength) radius = 150 m) 1.2 1.3 3.3.1 Required decoupling attenuation 3.1 4.1 The follow
32、ing tables contain all the interference situations studied in the analysis, together with their scenario numbers. The analysis covered both Co-channel operation and adjacent frequencies. The calculations for Co-channel operation were based on the information given in Table 1. The analysis of adjacen
33、t frequencies was based on the software programme “Mathcad“. The results are set out in Annex 3 (Table 2). 3.2 3.3 4.2 4.3 Interference scenario UIC Mobile Station held) I UIC Base Station I (39 dBm) UIC Base Station 45 dBm P- General calculation of the requisite decoupling attenuation 2.3 I 2.2 I 2
34、.1 I I L = pt(dBm) + g,(dBi) - p,(dBm) - C/I(dB) - g,(dBi) Abbreviations: pt: transmitter output power g,: transmitter antenna gain C: carrier to interferer value pr: receiver input power g,: receiver antenna gain Table 1: interference scenarious 3.3.2 Required separation distances The propagation m
35、odels described in 3.2 were used to determine the relevant separation distances. The results for the various interference scenarios are shown in Annex 3 both in tabular (Table 1) and graphic form (Figs 1 to 4). The propagation model used in each case is indicated. - NB The results for the operation
36、of radio microphones on adjacent frequencies are based on the receiver spectrum mask i Annex 4. However, this mask was originally developed for initial assessments of the interference situation in the frequency range 1785 - 1800 MHz and may change considerably owing to future developments in radio m
37、icrophone technology. 3.4 Interpretation of the results of the analysis 3.4.1 Use of the UICsystem The UIC system is intended to enable the railway operators to implement mobile communications. Mobile communications will not be restricted to the trains but will extend to service vehicles, staff and
38、other facilities. Coverage will therefore not be restricted to railway tracks but extend to adjacent areas as weil. This means that a distance of about i0 km on either side of the tracks should be covered. Dense urban areas will even be fully served by a cellular network. For these reasons the compa
39、tibility analysis was not simply limited to railway tracks. In some countries coverage may be extended to buses with an even wider range of operation. ERC REPORT 62 Pase 5 3.4.2 UIC mobile sfation interferes with radio niicropliones (scenarios I.1- 1.3 and 2, I - 2.3. See Tnble I) 3.4.2.1 Co-channel
40、 operation The results show that radio microphones are interfered with by mobile UIC stations located in trains. it is therefore not possible to operate a radio microphone in an area extending to approximately 750 m on either side of the tracks. In the range between roughly 750 m and 1.9 km the use
41、of microphones depends on their type of modulation and coverage range. Both factors affect the maximum permissible interfering field strength. In areas with few buildings the necessary separation distances may increase considerably, extending up to the radio horizon (ma. approx. 7 km). The parameter
42、s of UIC transmitters installed in service vehicles are the same as to those of stations in trains. For this reason the results for stations in trains also apply to service vehicles. Lower values are assumed for the power emitted by hand-held devices. The maximum transmitter power of such a device i
43、s about 30 dBm with an antenna gain of O dBi. For hand-held devices separation distances ranging from about 400 m to about 1 km have been determined. In view of the dense railway network in Europe and taking a service range of roughly 10 km on either side of the tracks and taking the establishment o
44、f cellular networks in urban areas into account considerable interference to radio microphones is inevitable. In rural areas the railway network may be less dense but the propagation conditions in relation to the interference situation are less favourable. All calculations are based on outdoor use o
45、f radio microphones. 3.4.2.2 Operation on adjacentjvquencies The results in Annex 3 (Figs 1 and 2) clearly show that a frequency separation of about at least f 600 kHz is necessary. However, in spite of such frequency separations, separation distances of about 60 m are also necessary. Here again, al
46、l calculations are based on outdoor use of radio microphones. 3.4.3 UIC base station interferes with radio microphones (scenarios 3.1 - 3.3 and 4.1 - 4.3. See Table I) 3.4.3.1 Co-channel operation If UIC usage as described in 3.4.1 is assumed a high number of base stations will be established, espec
47、ially in urban areas. Since the separation distances (see Annex3, Figs 3 and 4) extend to several kilometers (roughly 2.5 - 12 km) the use of radio microphones in this frequency range is also not possible. Isolation between the antennas of UIC base stations and radio microphones along tracks is not
48、feasible owing to the envisaged service range of about 10 krn on each side of the tracks. In rural areas the railway network may be less dense but the propagation conditions in relation to the interference situation are less favourable. All calculations are based on outdoor use of radio microphones.
49、 3.4.3.2 Operation on adjacent channels Here again, the results in Annex 3 (Figs 3 and 4) clearly show that a frequency separation of about tr. 600 kHz is necessary if distances of less than 400 m are to be achieved. But these distances are not always feasible, especially in urban areas. Furthermore, a frequency separation of about i 600 kHz implies a considerable restriction on the remaining frequency spectrum since UIC base stations use several channels. Ail calculations are based on outdoor use
