ITU-R S 741-2-1994 Carrier-to-Interference Calculations between Networks in the Fixed-Satellite Service《固定卫星网络载波干扰计算》.pdf
《ITU-R S 741-2-1994 Carrier-to-Interference Calculations between Networks in the Fixed-Satellite Service《固定卫星网络载波干扰计算》.pdf》由会员分享,可在线阅读,更多相关《ITU-R S 741-2-1994 Carrier-to-Interference Calculations between Networks in the Fixed-Satellite Service《固定卫星网络载波干扰计算》.pdf(5页珍藏版)》请在麦多课文档分享上搜索。
1、ITU-R RECMN*S= 741-2 94 Li855212 0523978 5b9 320 Rec. ITU-R 5.741-2 RECOMMENDATION ITU-R S.741-2 CARRIER-TO-INTERFERENCE CALCULATIONS BETWEEN NETWORKS IN THE FIXED-SATELLITE SERVICE (Question ITU-R 49/4) (1992-1993-1994) The ITU Radiocommunication Assembly, considering a) that during the planning st
2、age of a satellite network it may be useful to calculate carrier-to-interference (C/o ratios between carriers of the interfering and interfered-with networks for the purpose of determining levels of interference; b) cl performance degradation; that such calculations depend on the relative geometry o
3、f the satellite network involved; that the carrier-to-interference ratios can be used in the determination of interference levels contributing to d) e) networks in accordance with the Radio Regulations; f) of interference between satellite networks (see for example Recommendation IT-R S.740), that t
4、he carrier-to-interference ratios can be used for all modulation methods and signal types; that the carrier-to-interference calculation may be an element to complete frequency coordination of satellite that alternative methods may be used, by agreement between the administrations concerned, to calcu
5、late levels recommends 1. networks: that when carrier-to-interference ratios (Clis) are used to calculate the levels of interference between satellite - the method shown in Annex 2 of Recommendation ITU-R S.740 be used as the basis for these calculations in so far as geometrical considerations are c
6、oncerned; the methods given in Annex 1 to this Recommendation be used to calculate the interference power in the interfered- with carrier. - ANNEX 1 Determination of carrier-to-interference ratios and baseband noise power for coordination of carriers in the fixed-satellite service (FSS) 1. Types of
7、interfering carriers 1.1 The types of interference experienced by the FSS carriers from adjacent networks can be classified as follows: - noise-like interference; - slowly swept interference arising from a TV-FM carrier modulated only with an energy dispersal (ED) signal; interference from one TV-FM
8、 carrier to another (this category is not addressed in this Annex). - - ITU-R RECMN*S. 741-2 94 4855232 0523980 117 Rec. ITU-R S.741-2 32 1 2. Types of FSS carriers 2. I The types of carriers normally used in FSS networks are: - Analogue: - FDM-FM and CFDM-PM; - TV-FM; - single-channel-per-carrier (
9、SCPC)-FM. - Digitul: - - narrow-band and intermediate bandwidth carriers with and without FEC coding (e.g. SCPC-PSK); large bandwidth carriers (e.&. TDMA, CDMA). 3. Methodologies used to assess interference into FSS carriers 3. I Interference into FDM-FM and CFDM-FM carriers The effect of interferen
10、ce into FDM-FM or CFDM-FM carriers is treated in terms of the baseband interference noise power in a telephony channel and is given by the following expression: 10 log (np) = 87.5 - B - 10 log li) (1) where: tip : i? : c : i : The factor B depends on the signal characteristics of both the desired an
11、d the interfering carriers and the weighted interference power (pWOp) interference reduction factor (dB) power of the desired carrier (W) power of the interfering carrier (W). frequency separation belween the centre frequencies of the two carriers. The expressions for the interference reduction fact
12、or for all types of interfering carriers are given in Recommendation IT17-R SF.766. In the case of CFDM-FM, the applicable value of companding advantage (around 9 dB) should be considered along with the interference power level during speech excitation. 3.2 Interference into a non-FDM-FM carrier The
13、 assessment of interference into a non-FDM-FM carrier depends on the nature (Le. digital or analogue or slowly sweeping) of the interfering carrier and on whether the interfering carrier bandwidth is larger or smaller than the desired carrier occupied bandwidth. Table 1 shows the CI1 ratios for diff
14、erent combinations of the desired and interfering carriers. 3.3 Interference from noise-like digital carriers The ratio of the carrier to interference power in the desired carrier signal bandwidth, for Co-frequency operation of the desired and interfering carriers is given by: C/I = lOlog(c/i) - lOl
15、og(M) fOrBWD Bwia (2) C/Z = 10 log (di) - 10 log (BWD IBWI,) for BWu 5 BWla (3) where: CA : c: 1: ratio (dB) of desired carrier power and the total interference power in the desired carrier bandwidth power of the desired carrier (W) power of one interfering carrier (W) 322 Rec. JTU-R S.741-2 Digital
16、 narrow-band FDM-FM SCPC-FM CFDM-FM BW, occupied bandwidth of the desired carrier TV-FM Digital wide band BW, occupied bandwidth of the interfering carrier Not applicable BW/, : allocated bandwidth of the interfering carrier. C/I= IOlog(c/i)- 10 log (BW,/BW,) Expression (2) takes into account the ef
17、fect of multiple interfering carriers (M) affecting a desired carrier which has a large bandwidth. TABLE I Calculation of carrier-to-interference ratios for FSS carriers interfering carriers FDM-FM or CFDM-FM or with live modulation TV-FM SCPC-FM Or digital narrow- band Digital wideband TV-MF (Energ
18、y dispersal signal modulation only) Case B Wi, wD I Desired carriers I C/I= IOlog(/i)- 10log(BW/BWu) I Not applicable CI1 = 1 O log (di) - A C/I= IOIog(li)- 10 log (BWDIBW) CI1 = I O log (di) - I O log (B W,/ B Wi(,) See details in expression (i) or Rec. ITU-R SF.766 I C/I = 1 o log (di) I (Note i)
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
10000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ITURS74121994CARRIERTOINTERFERENCECALCULATIONSBETWEENNETWORKSINTHEFIXEDSATELLITESERVICE 固定 卫星网络 载波 干扰

链接地址:http://www.mydoc123.com/p-793703.html