1、Rec. ITU-R S.1429 1 RECOMMENDATION ITU-R S.1429 ERROR PERFORMANCE OBJECTIVES DUE TO INTERNETWORK INTERFERENCE REFERENCE DIGITAL PATHS OPERATING AT OR ABOVE THE PRIMARY RATE CARRIED BY SYSTEMS USING FREQUENCIES BELOW 15 GHz BETWEEN GSO AND NON-GSO FSS SYSTEMS FOR HYPOTHETICAL (Questions ITU-R 73/4 an
2、d ITU-R 75/4) (2000) The ITU Radiocommunication Assembly, considering a) that interference between GSO and non-GSO FSS systems can be of a short-term name; b) utilizing fi-equencies below 15 GHz are given in Recommendation ITU-R S. 1062; that error performance objectives for satellite digital paths
3、operating at or above the primary rate with systems c) expressed in terms of errored seconds (ES) and severely errored seconds (SES); that the error performance objectives for satellite digital paths given in Recommendation ITU-R S.1062 can be 4 that sharing considerations between FSS systems carryi
4、ng digital trafic are given in Recommen- dations ITU-R S.735 and ITU-R S.1323; e) time allowance for a given BER that Recommendation ITU-R S.1323 requires that time varying interference be responsible for at most 10% of I) that availability objectives for satellite digital paths are given in Recomme
5、ndation ITU-R S.579, recommends 1 that, for satellite hypothetical reference digital paths (HRDPs) operating at or above the primary rate, 10% of the error performance objectives for these HRDPs be allotted to short-term interference between GSO and non-GSO FSS systems. These allotments are shown in
6、 terms of bit error probability (BEP) in Table 1. Tables 2 and 3 give the objectives in terms of ES and SES (see Note 1). NOTE 1 - The technical basis for the interference allotments is given in Annex 1. NOTE 2 - This Recommendation should be used in conjunction with Recommendation ITU-R S.1062. 2 B
7、it rate (Mbis) 1.5 2.0 6.0 51.0 155(2) Rec. ITU-R S.1429 TABLE 1 Ailowable BEPs due to short-term interference between GSO and non-GSO FSS systems BE PI() 0.02 7 x 10-7 0.2 3 x 10-8 1 .o 5 x 10-9 0.02 7 x 10-6 0.2 2 x 10-8 1 .o 2 x 10-9 0.02 8 x 10-7 1 .o i x 10-9 0.02 4 x 10-7 0.2 2 x 10-9 1 .o 2 x
8、 10-10 0.02 i x 10-7 0.2 i x 10-9 Percentage of total time (worst month) 0.2 1 x 10-8 1 .o 1 x 10-10 Bit rate (Mbis) Allowable ES per day Allowable SES per day Allowable errored interval objectives due to short-term interference which correspond to the BEPs given in Tables 1 and 2 of Recommendation
9、ITU-R S.1062 are shown in the following Tables. These values are obtained by taking 10% of the errored interval objectives computed using the method given in Annex 1 of Recommendation ITU-R S.1062. 1.5-5 5-15 15-55 55-160 121 151 226 483 6 6 6 6 TABLE 2 Ailowable errored interval objectives due to s
10、hort-term interference between GSO and non-GSO FSS systems for systems using the objectives of Table 1 of Recommendation ITU-R S.1062 Rec. ITU-R S.1429 Bit rate (mitis) Allowable ES per day Allowable SES per day 3 1.5-5 5-15 15-60 60-155 13 31 116 483 OU) OU) OU) 6 TABLE 3 Ailowable errored interval
11、 objectives due to short-term interference between GSO and non-GSO FSS systems for systems using the objectives of Table 2 of Recommendation ITU-R S.1062 NOTE 1 -The BEPs given in Table 2 of Recommendation ITU-R S.1062 and referenced in Note 2 of that Recom- mendation are to be used when more string
12、ent performance is desired or when carriage of certain trafic requires it. ANNEX 1 Apportioning error performance objectives due to short-term interference 1 Introduction With the initiation of non-GSO FSS systems, it has become necessary to consider the allocation of error performance objectives du
13、e to time varying name interference between GSO and non-GSO FSS systems. This Annex provides the rationale for the apportionment of error performance objectives due to short-term interference by relating the sharing cri- teria in Recommendation ITU-R S.1323 and the error performance objectives given
14、 in Recommendation ITU-R S.1062. 2 Error performance objectives Error performance objectives for FSS systems providing digital paths operating at or above the primary rate are given in Recommendation ITU-R S.1062. This Recommendation contains a detailed exposition of how those objectives can be appl
15、ied to the design of FSS digital paths. Most useful to satellite system designers are error objectives in terms of BEPs which can be directly related to required carrier-to-noise ratios (UNS). Recommendation ITU-R S.1062 provides the techniques needed to equate errored interval requirements given in
16、 terms of ES and SES to required BEPs as a function of time. Recommendation ITU-R S.1062 includes a set of BEP objectives, in Table 2, that meet the ITU-T requirements at 155.52 Mbit/s and are better than the required performance at lower bit rates. These BEPs are referenced in Note 2 of that Recomm
17、endation and are to be used when more stringent performance is desired or when the carriage of certain traffic services requires it. Allowable errored interval objectives due to short-term interference which correspond to these BEPs can be obtained by taking 10% of the errored interval objectives co
18、mputed using the method given in Annex 1 of Recommendation ITU-R S. 1062. 4 Rec. ITU-R S.1429 1.5-5 Bit rate (Mbis) 3 Sharing criteria 5-15 15-55 55-160 Sharing criteria for FSS networks carrying digital traffic are given in Recommendations ITU-R S.735 and ITU-R S.1323. Specifically, Recommendation
19、ITU-R S. 1323 provides guidance on the allowable interference between networks that is of a time varying nature. This allotment is 10% of the time allowance for given BEPs according to Recommen- dation ITU-R S.1062. Allowed ES per day (Note 1 of Recommendation ITU-R S.1062) Allowed ES per day (Note
20、2 of Recommendation ITU-R S.1062) 4 Interference apportionment 121 151 226 484 13 31 116 483 Given the 10% apportionment for short-term interference fiom Recommendation ITU-R S.1323, the BEP objectives are determined simply by taking 10% of the BEP objectives for the overall path performance. These
21、results are shown in Table 1 of the preceding Recommendation. Allowed SES per day (Note 1 of Recommendation ITU-R S.1062) Allowed SES per day (Note 2 of Recommendation ITU-R S.1062) The 10% apportionment is applied to the errored interval objectives on a daily basis. Recommendation ITU-R S.1062 note
22、s that satellite HRDPs must be available 99.96% of a year. This implies that on an average daily basis, since there are 86 400 s in a calendar day, applying this availability standard indicates that 35 s will be unavailable, leaving 86 365 s in the available time. It must be noted that not all days
23、are average and that the number of unavailable seconds may be more or less than 35 depending upon conditions including propagation. For the purpose of allocating intersystem interference, it has been assumed that there are 35 unavailable seconds per day. 6 6 6 6 O O O 6 Table 4 summarizes the requir
24、ements of Recommendation ITU-R S.1062 and provides the corresponding apportionment for short-term interference. The requirements for ES are contained in the errored second ratio (ESR) and the require- ments for SES are contained in the severely errored second ratio (SESR). TABLE 4 AUowable error per
25、formance objectives due to short-term interference between GSO and non-GSO FSS systems 5 Summary This Annex has provided the technical rationale for the apportionment of error objectives due to short-term interference into a satellite HRDP operating at or above 1.5 Mbit/s. This apportionment is achieved through using the error objectives given in Recommendation ITU-R S.1062 and applying the sharing criteria given in Recommendation ITU-R S.1323.
