E-Mail generated [Mar 29 2018]

0832-EX-CN-2017 Correspondence

Aerospace Corporation, The

2018-03-29ELS_207237

Douglas Young From: Douglas Young Sent: Thursday, March 29, 2018 1:32 PM To: 'David A Hinkley' Subject: Request for Info - File # 0832-EX-CN-2017 Attachments: Interference Guide902-928MHz.pdf Importance: High Provide an interference analysis in accordance with the attachment. The items indicated above must be submitted before processing can continue on the above referenced application. Failure to provide the requested information within 30 days of March 29, 2018 may result in application dismissal pursuant to Section 5.67 and forfeiture of the filing fee pursuant to Section 1.1108. 1

Potentialinterference to the land mobile service from the NGSO networks (CubSat) in the band 902—928MHz TSD / 2 March 2017 1 Introduction Recently the Radiocommunication Bureau (BR) has received several NGSO filings for the space operation or space research services in the frequency band 902—928 MHz under No. 4.4 ofthe Radio Regulations (RR) since this frequency band has no allocation to any space service. On the terrestrial part, 20 467 frequency assignments ofthe land mobile service in the band 902—928 MHz are currently recorded in the MIFR. This document contains the result of assessment of the interference from some US space stations notified to the BR. 2 Formulas and assumptions a mobile service station is located at nadir of a CubSat at 450 — 550 km; parameters of a CubSat space station are taken from the US filings; protection requirements of IMT are calculated using the relevant ITU—R deliverables, as below; free space propagation model is used for the interference assessment; interference are estimated by comparing the field strength produced by CubSat at the IMT antenna with the values ofthe field strength to be protected for IMT stations; single source interference impact is assessed; IMT antenna pattern and the difference in the bandwidthsare taken into account. 3 Protection criteria for the IMT systems The protection criteria of /N =—6 is recommended for GSM and LTE systems and /N=—9dB for GSM— R system. TABLE 1 shows the field strength to be protected in the frequency band 880—960 MHz, which are calculated using the system characteristics given in Report ITU—R M.2039 and ECC Reports 082 and 096. TABLE 1 Field strength to be protected for land mobile service systems System Class of Frequency Noise Feeder Receiving Field strength to be protected Receiving to be station (MHz) Figure Loss antenna (dBuV/m) antenna protected (dB) (dB) gain (dBi) at 200 kHz 200 kHz 5 MHz height (m) 90° GSM—R GSM LTE G8M or Receiving —1.5* LTE b ase station ; 880—915 $ 3 s (G mas 15) 16 19 33 30 system Receiving 0 (GSM—R mobile 925—960 $ 0 and GSM) 15 18 38 15 station —3 (LTE) * —1.5 dB of omnidirectional vertical antenna gain at the elevation angle of 90 degree as the worst case is used for calculation. (See recommends 2.2 of Recommendation ITU—R F.1336—4). The field strengths (£) to be protected are calculated using the following equation: E=—37 + F—G,(0)+ Lr+ 10 log (B,) + 20 log (f) + I/N (Recommendation ITU—R M.1767) where:

F : receiving station noise figure (dB) G0) : receiver antenna gain (dBi) at the elevation angle of 0 Lr : receiving station antenna cable feeder loss (dB) B, : receiving bandwidth (MHz) [ : center frequency ofthe receiving station (MHz) LN : interference to noise ratio (dB) 4 Field strength produced by the space stations Based on the parameters notified to the BR, the calculations are made to determine the field strength produced at the surface of the Earth from thesatellites for every notice. The results are listed in TABLE 2 with potential interference possibility. For the calculation ofthe field strength produced by the space stations in question, free space propagation model is used (see Recommendation ITU—R P.525—3). TABLE 2 Field strength produced by the space stations and potential interference possibility Field Strength on Excess of Interference, dB Parameters of NGSO space station notified to the BR earth surface *N‘: nointerference (dBuV/m) *—* : nofrequency overlap Qee Brip frea_mi '"‘%“" “::;"- Bandwidt EIRP 200 § gshl:; car car Lt Lt ()\/ n (MHz) (MBH2) (Kom) h (MHz) (dBW) kHz MHz Bs M BS M \t} { 114540737 914.085 915315 450 L1 3 17 25 * N — N — 114540757 914.085 915.315 450 123 3 17 25 * N — N — 115545029 902 928 500 0.15 72 14 14 N N N N N 115545029 902 928 500 0.25 2.8 23 24 N N 115545029 902 928 500 0.35 28 21 24 N N 115545029 902 928 500 0.5 2.8 20 24 N N 115545029 902 928 500 0.05 —12 9 9 N N N N N '(/-9 i 116545202 914.085 915315 550 1.09 10 14 30 + N — N — * 116545202 914.085 915315 550 1.09 10 14 30 ~ N — N — gq 116545207 9234 923.6 550 0.164 —10.5 9 9 N — — — — * The field strength produced by the space station has been normalized to meet the bandwidth of the victim receiver. § Conclusion If the notified NGSO satellites are broughtinto use without mitigation measures, some transmissions from the space stations of one among the four assessed satellite networks could cause interference to GSM systems with the excess of interference above the permissible level by 8 dB maximum. No interference to LTE is expected


Document Created: 2018-03-29 13:34:58
Document Modified: 2018-03-29 13:34:58
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