1、Rec. ITU-R F.1243 1RECOMMENDATION ITU-R F.1243*RADIO-FREQUENCY CHANNEL ARRANGEMENTS FOR DIGITALRADIO SYSTEMS OPERATING IN THE RANGE 2 290-2 670 MHz(Question ITU-R 136/9)(1997)Rec. ITU-R F.1243The ITU Radiocommunication Assembly,consideringa) that as a result of the World Administrative Radio Confere
2、nce for Dealing with Frequency Allocations inCertain Parts of the Spectrum (Malaga-Torremolinos, 1992) (WARC-92) many administrations may wish to plan fixedservices around the bands designated for new mobile and mobile-satellite services;b) that it is sometimes desirable to be able to interconnect l
3、ow and medium capacity digital radio systems oninternational circuits using radio frequencies in the 2 GHz band;c) that many interfering effects can be substantially reduced by a carefully planned arrangement of the radiofrequencies in radio systems employing several radio-frequency channels;d) that
4、 sharing between the fixed satellite (FS) and mobile service (MS) or mobile-satellite service (MSS) may bepossible by using adequate geographical and/or frequency separation;e) that administrations may have different requirements for sharing spectrum with the FS, and they may notrequire all the spec
5、trum allocated to MS or MSS;f) that the use of industrial, scientific and medical (ISM) devices in the band 2 400-2 500 MHz may causeharmful interference to systems in the FS,recommends1 that where the introduction of MS and MSS limits the FS to the band 2 520-2 670 MHz, a radio-frequencychannel arr
6、angement with up to five go and return channels is used (carrier spacing of 14 MHz), which is derived asfollows:let f0be the band centre frequency of 2 595 MHz,fnbe the centre frequency of a radio-frequency channel in the lower half of the band,fnbe the centre frequency of a radio-frequency channel
7、in the upper half of the band,DS (Tx/Rx duplex spacing) = 74 MHz,then the frequencies of individual channels with a carrier spacing of 14 MHz are expressed by the followingrelationships:lower half of band: fn= f0 79 + 14 n MHzupper half of band: fn= f0 5 + 14 n MHzwhere n = 1, 2, 3, 4 or 5.The frequ
8、encies of individual channels of channel arrangements with carrier spacings of 7, 3.5 and 1.75 MHz areexpressed by the following relationships:Carrier spacing of 7 MHz:lower half of band: fn= f0 75.5 + 7 n MHzupper half of band: fn= f0 1.5 + 7 n MHzwhere n = 1, 2, 3, . 10._*This Recommendation shoul
9、d be brought to the attention of Radiocommunication Study Groups 10 and 11 (WP 10-11S).2 Rec. ITU-R F.1243Carrier spacing of 3.5 MHz:lower half of band: fn= f0 73.75 + 3.5 n MHzupper half of band: fn= f0+ 0.25 + 3.5 n MHzwhere n = 1, 2, 3, . 20.Carrier spacing of 1.75 MHz:lower half of band: fn= f0
10、72.875 + 1.75 n MHzupper half of band: fn= f0+ 1.125 + 1.75 n MHzwhere n = 1, 2, 3, . 40;2 that where the introduction of MS and MSS limits the FS to the band 2 520-2 670 MHz, a radio-frequencychannel arrangement, alternative to that reported in 1 and using the same band centre frequency and duplex
11、spacing,with carrier spacing of 2 MHz can be accommodated with up to 35 go and return channels, the frequencies of individualchannels being expressed by the following relationships:lower half of band: fn= f0 73 + 2 n MHzupper half of band: fn= f0+ 1 + 2 n MHzwhere n = 1, 2, 3, . 35.For lower carrier
12、 spacings, the frequencies of individual channels are expressed by the following relationships:Carrier spacing of 1 MHz:lower half of band: fn= f0 72.5 + 1 n MHzupper half of band: fn= f0+ 1.5 + 1 n MHzwhere n = 1, 2, 3, . 70.Carrier spacing of 0.5 MHz:lower half of band: fn= f0 72.25 + 0.5 n MHzupp
13、er half of band: fn= f0+ 1.75 + 0.5 n MHzwhere n = 1, 2, 3, . 140.Carrier spacing of 0.25 MHz:lower half of band: fn= f0 72.125 + 0.25 n MHzupper half of band: fn= f0+ 1.875 + 0.25 n MHzwhere n = 1, 2, 3, . 280.Channel arrangements with lower carrier spacings are possible by means of further channel
14、 subdivision;3 that where coexistence in the sub-band 2 590-2 670 MHz of different FS applications is difficult,the radio-frequency channel arrangement be based on utilizing the band 2 290-2 360 MHz paired with theband 2 520-2 590 MHz and a homogeneous pattern with a carrier spacing of 2.5 MHz defined by the following relations:lower half of band: fp= fr 306.25 + 2.5pupper half of band: fp= fr 76.25 + 2.5pwhere:p = 1, 2, 3, 28fr: reference frequency of the homogeneous patternfr= 2 595 MHz._
