1、 CEPT CEPT/ERC/REC 14-02xE 95 2326434 0013007 O99 W CEPTIERCIREC 14-02 E Page 1 Distribution: B CEPT/ERC/RECOMMENDATiON 14-02 E (Bonn 1995) RADIO-FREQUENCY CHANNEL ARRANGEMENTS FOR MEDIUM AND HIGH CAPACITY ANALOGUE OR HIGH CAPACITY DIGITAL RADIO-RELAY SYSTEMS OPERATING iN THE BAND 6425 MHz - 7125 MH
2、z Recommendation proposed by the Working Group “Spectrum Engineering“ (WGSE) Text of the Recommendation aopted by the “Eiiropeun Radiocommunications Committee“ (ERC): “The European Conference of Postal and Telecommunications Administrations, considering that radio-relay systems with a capacity of 27
3、00 telephone channels should prove to be feasible in the 6 GHz band, if due care is exercised in the planning of radio paths to reduce multipath effects, that it is sometimes desirable to be able to interconnect, at radio frequencies, radio-relay systems on international circuits in the 6 GHz band.
4、that it may be desirable to interconnect up to eight go and eight return channels in a frequency band 680 MHz wide, that economy may be achieved if at least four go and four return channels can be interconnected between radio-relay systems, each of which uses common transinit-receive antennas, that
5、a common radio-frequency channel arrangement for both up to 1260 and 2700 telephone channel radio-relay systems offers considerable advantages, that the use of certain types of digital modulation see Recommendation IU-R F. 1 IO i) permits the use of the radio-frequency channel arrangement defined fo
6、r 2700 telephone channel systems for the transmission of digital channels with a bit rate of the order of I40 Mbit/s or synchronous digital hierarchy bit rates, that for these digital 140 Mbit/s radio systems, further economies are possible by accommodating up to eight go and return channels on a si
7、ngle antenna with suitable performance characteristics, that many interfering effects can be reduced substantially by a carefully planned arrangement of the radio frequencies in radio-relay systems employing several radio-frequency channels, that the radio-frequency channels should be so arranged th
8、at an intermediate frequency of 70 MHz may be used for up to 1260 channel systems, 10) that the radio-frequency channels should be so arranged that an intermediate frequency of 140 MHz may be employed for 2700 channel systems, Il) that single- and niulti-carrier digital radio-relay systems are both
9、useful concepts to achieve the best technical and economic trade-off in system design, 12) there are technical and economical advantages in adopting Iiarmonised channel plans, Bdition of August 26, 1996 CEPT CEPT/ERC/REC L4-02aE 95 W 232b414 O013008 T25 CEPTIERCIREC 14-02 E Page 2 noting a) that thi
10、s recommendation is based on the ITU-R Recommendation F.384, recommends that the preferred radio-frequency channel arrangement for up to eight go and eight return channels, each accommodating 2700 telephone channels, or a bit rate of the order of 140 Mbits, or synchronous digital hierarchy bit rates
11、 (Note i), and operating at frequencies in the upper 6 GHz band, should be as shown in Annex I (Note 2), that, in the section over which the international connection is arranged, all the go channels should be in one half on the band, and all the return channels should be in the other half of the ban
12、d, that different polarisations should be used alternately for adjacent radio-frequency channels in the same half of the band, that, when common transmit-receive antennas are used, and not more than four channels are accommodated on a single antenna, it is preferred that the channel frequencies be s
13、elected by making either: n = i, 3,s and 7 in both halves of the band or n = 2,4,6 and 8 in both halves of the band (Annex I, Section 3), that the preferred arrangement of radio-frequency polarisation should be one of those shown in Figure 1 (Annex I), that a Co-channel arrangement may also be used
14、for digital radio-relay systems which can be derived from the arrangements given in Figure I (Annex I), that the preferred radio-frequency channel arrangement for up to i6 go and 16 return channels, each accommodating up to 1260 telephone channels, or the equivalent, or digital plesiochronous or syn
15、chronous medium capacity rates, should be obtained by interleaving as shown at Annex II (Note 3), that, in the section over which international connection is arranged, all the go channels should be in one half of the band, that different polarisations should be used alternately for adjacent radio-fr
16、equency channels in the same half of the band, Note 1 : Actual gross bit rates including overhead may be as much as 5% or more higher than net transmission rates. Note 2: This radio-frequency channel arrangement permits all local oscillator frequencies to be derived from a common oscillator, if desi
17、red. Note 3: The radio-frequency channel arrangements for systems of up to 1260 channel capacity and of 2700 channel capacity may be used on intersecting routes, as long as adequate antenna discrimination is provided. Edition of August 26, 1996 CEPT CEPT/ERC/REC 14-02*E 95 M 2326434 0033009 963 CEPT
18、IERCIREC 1442 E Page 3 I O) that when common transmit-receive antennas are used, and not more than four radio-frequency channels are accommodated on a single antenna, it is preferred that the channel frequencies by selected by making either: N = 1, 5, 9, 13 or N = 2,6, 10, 14 or N=3,7, 11, 15or N =4
19、, 8, 12, 16, in both halves of the bands and the preferred arrangement of radio-frequency polarisation is as shown in Figure I (Annex I). 11) that if multi-carrier transmission (Note 4) is employed, the overall number of n carriers will be regarded as a single channel. The centre frequency of that c
20、hannel should be derived from recommends 1 or recommends 7, disregarding the actual centre frequencies of the individual carriers, which may vary, for technical reasons, according to practical implementations. Operation of multi-carrier systems is addressed in greater detail in Annex II, 12) that th
21、e preferred centre frequency (JO) is 6770 MHz; other centre frequencies may be used by agreement between the administrations concerned.” Note 4: A multi-carrier system is a system with n (where nl) digitally modulated carrier signals simultaneously transmitted (or received) by the same radio-frequen
22、cy equipment. The centre frequency should be regarded as the arithmetic average of the n individual carrier frequencies of the multi-carrier system. Edition of August 26, I996 CEPTIERCIREC 14-02 E Page 4 Left blank Edition of August 26, 1996 CEPT CEPT/ERC/REC L4-02*E 95 m 2326434 OOL30LL 5LT I CEPTI
23、ERCIREC 94-02 E Annex I, Page 1 Annex I 1. DERIVATION OF RADIO FREQUENCY CHANNELS The radio frequency channel arrangement for carrier spacings of 40 MHz and 20 MHz shall be derived as follows: Let fo be the frequency (MHz) of the centre of the band of frequencies occupied, fn be the centre frequency
24、 (MI-Iz) of one radio-frequency channel in the lower half of the band, fil be the centre frequency (MHz) of one radio-frequency channel in the upper half of the band, then the frequencies (MHz) of individual channels are expressed by the following relationships: a) for systems with a carrier spacing
25、 of 40 MHz: lower half of the band: upper half of the band: fn = fo - 350 -t 40 n fn-fo- 10+40ii where n = i, 2, 3,4, 5,6,7 or 8 b) for systems with a carrier spacing of 20 MI-Iz: upper half of the band: lower half of the band: fn = f0 - 350 +20 i1 fn=fo- 10+20n where n = 1,2,3, . 16 2. CALCULATED P
26、ARAMETERS ACCORDING TO ITU-R REC. 746 Z 1 S: lower guard band Z2S: upper guard band Edition o August 26, I936 - - CEPT CEPT/ERC/REC LY-OZ*E 95 23264LY OOL3OL2 456 CEPT/ERC/REC 1402 E Annex I, Page 2 3. OCCUPIED SPECTRUM: 6425 - 7125 MHz Figure 1 20 4-+ i 25 k-+ 6425 MHz 7125 MHz a) Channel arrangeme
27、nt for antennas with double polarisation b) Channel arrangement for antennas with single polarisation - all frequencies are in MHz; - the use of a single antenna working allows for seven go and return channels of 40 MHz with the channel arrangement of Fig. 1 (b). The channel arrangement of Fig. 1 (a
28、) and suitable antenna performance gives higher isolation between transmit and receive channels, allowing the use of the eight go and return channels of 40 MHz. Edition of August 26, 1996 CEPT CEPT/ERC/REC L4-02*E 95 m 2326414 00130L3 392 m CEPTIERCIREC 14-02 E Annex II, Page 1 Annex II DESCRIPTION
29、OF A MULTI-CARRIER SYSTEM A multi-carrier system is a system with n (where nl) digitally modulated carrier signals simultaneously transmitted (or received) by the same radio-frequency equipment. For high capacity multi-carrier transmission, the centre frequency of the channel should coincide with on
30、e of the corresponding frequencies of the basic channel arrangements given in recommends i or recommends 7. The channel spacing may be an integer multiple of the basic values defined by recommends 1 or recommends 7. Compatibility with existing configurations has to be taken into account when choosin
31、g the appropriate alternative. Examples of Co-polar channel arrangements using a two-carrier system with 64 QAM are shown below. Each carrier is modulated with 155.52 MbWs (STM-I radio relay system). In a mixed analogue/digital environment the arrangement shown in Fig. 2 (a) is preferred because it
32、places the carrier frequencies of the existing analogue system in the middle of the digital carrier pairs. The centre frequencies of this channel arrangement are derived from recommends 1 by setting n = 2, 4, 6, 8. Channel spacing is 80 MHz. Each RF-channel contains 2 x 2 carriers allocated at +17.5
33、 MHz around the centre frequency using both polarisations. Fig. 2 (b) shows an interleaved channel arrangement where centre frequencies are derived from recommends 7 by setting N = 3, 7, 11, 15. This channel arrangement is adequate in a purely digital environment and is preferred because it provides
34、 more symmetrical guardbands at the band edges. Edition ofAugust 26. i996 CEPT CEPT/ERC/REC 14-02rE 95 m 2326414 OOL3014 229 m 6480 6560 6640 6720 CEPTIERCIREC 14-02 E Annex II, Page 2 6820 6900 6980 7060 Figure 2 Example of radio-frequency channel arrangements for a 2 x 2 x 155.52 Mbit/s (STM-1 rad
35、io-relay system) operating with 80 MHz channel spacing in the upper 6 GHz band 6770 (a) Channel arrangement preferred if compatibility with analogue radio-relay systems is required. (b) Channel arrangement preferred if compatibility with analogue radio-relay systems is not required. - all frequencies are in MHz. Edition of August 26, 1996
