Hughes’ 47 GHz UMFUS Compatibility Analyses October 29, 2020
Overview • In 2017, HNS License Sub, LLC (HNS) filed an application for 20 earth stations to support a new GSO satellite, Jupiter 3 (a.k.a., Echostar XXIV or HNS 95W), planned to be positioned at 95W – The application included an initial 25.136(a)(4) compatibility analysis for the 27.5-28.35 GHz band (28 GHz) • In 2019, HNS amended that application to, among other things, make minor changes to site coordinates and increase EIRP – The amendment included a revised 25.136(a)(4) analysis for 28 GHz and a new 25.136(d)(4) analysis for the 47.2-48.2 GHz band (47 GHz) • On January 31 and February 11, 2020, HNS submitted supplemental letters that further revised its 25.136(a)(4) and (d)(4) analyses for 28 GHz and 47 GHz, respectively • The February 11 th HNS narrative for 47 GHz states that its filing includes revised PFD contours “consisting of 250 -meter (in radius) circles and PFD contours drawn using Recommendation ITU-R P.2108 to account for clutter loss (with an assumed p value of 85 %)” • The narrative further states the HNS analysis “assumed no clutter loss for transmission distances less than 250 meters” • Although the exact methodology and assumptions that HNS used are unclear from the information provided, it appears that HNS implemented clutter losses incorrectly, and as a result HNS grossly under- predicted the size of the company’s -77.6 dBm/m 2 /MHz earth station contours • All 20 HNS contours are nearly identical circles, each with a radius of approximately 250 meters around the earth station – This type of rigid uniformity among what should be site-specific showings strongly suggests HNS has erred 2
HNS’s Implementation of P.2108 • Annex 1 of Recommendation P.2108 includes three clutter loss models, but only the model in § 3.2 applies to 25.136(a) or (d) – The model in § 3.1 is only applicable to frequencies between 0.03 and 3 GHz – The model in § 3.3 is only applicable to links in which one terminal is “a satellite, aeroplane or other platform above the surface of the Earth” • The model in § 3.2 is intended to provide “a statistical distribution of clutter loss” – The model provides a distribution of losses for statistical, Monte Carlo modeling, not a single value of clutter loss for a deterministic analysis such as HNS’s – Also, P.2108 states that this the model “can be applied for urban and suburban clutter loss modelling” • Footnote 2 of HNS’s February 11 th letter references ITU sharing studies completed by ITU-R Task Group 5/1 and states that, “[t]he sharing studies used a random value of p, ranging from 1 to 100%, resulting in an average p value of 50 %” – That document also states that the model in P.2108 “is designed to be statistical and is used when precise knowledge of the r adio path is not known such as the width of streets, heights of buildings, depth of vegetation and location of the interferer and victim.” – Recent FCC guidance affirms that “Applicants should not use statistical models to estimate clutter loss when there are more a ccurate means of estimating clutter loss ”. See Public Notice, Report No. SPB-281 at 3 (rel. June 16, 2020). – In the case of an FSS earth station in a known location communicating with a “fixed” GSO satellite, the precise radio path an d surroundings are – and have been – very well known • HNS provides no explanation of why (or how) it applied an “assumed p value of 85 %” when the value of “p” is intended to be random • The equations in § 3.2 give a loss of nearly 30 dB for a “p” value of 85% over a 251 meter distance (one meter past the limit in which the model no longer applies) – This output only means that 85% of locations that are 251 meters from the earth station will have clutter loss that is less than 30 dB – This does not mean that the clutter loss 251 meters from the earth station is always 30 dB 3
The Evolution of HNS’s Contours (Boise, ID Example) 28 28 GHz 47 47 GHz 20 2017 N/A (SES-LIC-20170807-00876 to 00895) 2019 20 (SES-AMD-20190221-00282 to 00310) 20 2020 (1/31/2020 and 2/11/2020 Supplemental Letters) All All HNS HNS co contours rs include clu clutt tter r loss , but t th the 2020 re revisions imp mplemented th the P.2108 req requirement t th that clutt clutter r losses do o not t ap apply y to o dista tances les ess th than 250 meters rs. 4
HNS 47 GHz Contours Fla lagstaff ff, AZ Boise se, ID Bend, OR Nort rth Las s Veg egas, NV Rapid id Cit ity, SD Bil illi lings, s, MT Nort rth Plat latte, NE Tuc Tucso son, AZ Cheyenne, WY Sim imi i Vall lley ey, CA Qui uincy, WA Lin indon, UT Yu Yuma, AZ Reno, NV Taos, Ta s, NM Dr Driggs, ID Mis issoula, la, MT Bism ismarc rck, ND Santa Cla lara ra, CA Rif ifle, CO 5
HNS 28 GHz vs. 47 GHz Contours Flagstaff, , AZ Ren eno, NV NV 47 47 GHz 28 28 GHz HNS’s 28 GHz contours are roughly the same size (250 meter radius) as their 47 GHz contours with the exception of two back lo be protrusions which are less visible at 47 GHz 6
Visual Comparison: SpaceX 28 GHz Contour vs. Common HNS Contour • The map shows how an HNS 250-meter calculated contour would compare to a SpaceX 28 GHz contour if HNS were to use its contour-calculation method at a SpaceX earth station site SpaceX calculated contour (orangeline) • Although one would expect -77 dBm/m 2 /MHz contours for GSO and NGSO earth stations to differ, the parameters below cannot justify the orders of magnitude differences seen on the map of contours depicted in the image to the left Parameter SpaceX Sp HNS Satellite Type NGSO GSO Worst Case EIRP -15.7 dBW/MHz -21.1 dBW/MHz toward horizon HNS hypothetical 250 meter contour (blu lueline) ~40 ⁰ to 50 ⁰ , Minimum Elevation 25 ⁰ Angle depending on latitude Clutter Losses No Yes • Even if HNS were to follow the same method as other GSO operators have used, simply accounting for HNS’s -21.1 dBW/MHz EIRP to the horizon would result in a contour many times larger than the 250-meter contour it shows regardless of site location As explained previously, HNS’s 28 GHz and 47 GHz contours are very similar; therefore, the HNS contour depicted here is representative of either a 28 GHz or 47 GHz HNS earth station at this level of resolution. 7
Clutter? • The clutter loss model used by HNS was intended for urban and suburban areas, yet HNS applied clutter loss to all 20 earth stations • The -77.6 dBm/m 2 /MHz threshold is required to apply 10 meters above ground level (AGL) HNS Si HN Site e in in No North Platt tte, NE NE (A (Aeri rial View) • The pictures to the right show one of many examples of a HNS earth station with no visible clutter, especially at 10 meters AGL • The contours should instead rely on local terrain information and only apply clutter losses if the local geography warrants it • Other applicants have shown more prudence in their application of clutter loss HN HNS Si Site e in in No North Platt tte, NE NE (S (Street Vie iew) O3b’s Hawaii mPower er Gateway “ Because of the absence of artificial obstacles surrounding the site, O3b did not conduct a clutter analysis ” 8
Possible Next Steps • Clarify methodology for calculating earth station contours by issuing a declaratory ruling under section 1.2 of the Commission’s rules and direct licensees to update past filings under section 25.111 of the Commission’s rules to reflect the correct methodology to use in identifying earth station contours • Modify or, if necessary, rescind previously granted earth station licenses to correct for flawed calculations pursuant to section 316 of the Communications Act 9
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