Reply to Boeing F.pd

REPLY submitted by Iridium Satellite LLC

Reply of Iridium Satellite LLC

2012-07-11

This document pretains to SES-MOD-20120403-00326 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2012040300326_959186

                                    Before the
                     FEDERAL COMMUNICATIONS COMMISSION
                              Washington, D.C. 20554


In the Matter of                               )
                                               )
The Boeing Company                             )       File No. SES-MOD-20120403-00326
                                               )
Application for Modification                   )
of Earth Station License                       )


                            REPLY OF IRIDIUM SATELLITE LLC

       On June 15, 2012, Iridium Satellite LLC (“Iridium”) filed a Petition to Dismiss the

above-captioned application filed by The Boeing Company (“Boeing”). On June 28,

2012, Boeing filed an Opposition, and on July 9, 2012, Boeing supplemented its prior

filings with a technical analysis. 1 Iridium hereby replies to Boeing’s Opposition.


       Iridium filed its Petition to Dismiss because Boeing had not addressed, as is

required by Section 25.203(k) of the Commission’s rules, the potential for Boeing’s

proposed operations to cause unacceptable interference to Iridium’s non-geostationary

satellite orbit (“NGSO”), mobile satellite service feeder links and TT&C links in the

29.25-29.3 GHz band. Based upon the information subsequently submitted in Boeing’s

Supplemental Engineering Showing, Iridium no longer has an objection to a grant of




1Letter from Bruce A. Olcott to Marlene H. Dortch, SES-MOD-20120403-00326 (July 9, 2012), and an
attached “Analysis of Potential Interference to the Iridium Feeder Links” (“Supplemental Engineering
Showing”).


                                                    -2-


Boeing’s application. 2 Iridium wishes, however, to clarify certain matters that bear on

Boeing’s Supplemental Engineering Showing and on future showings that may be

made.


        Potential interference to Iridium’s other feeder link/TT&C link facilities.

Boeing’s interference analysis is limited to the potential impact on Iridium’s operations

in Tempe, Arizona, even though there are several additional locations in North America

at which feeder link/TT&C link facilities are operated that communicate with Iridium’s

satellite system. Iridium does not believe, given the location of Boeing’s earth station,

that taking these additional facilities into account would have had a material impact on

Boeing’s technical analysis. That may not be true, however, for analyses submitted by

Boeing or other applicants in the future.


        Analysis should not be limited to C/I. Carrier-to-Interference ratio (C/I) should

not be the only criterion considered with respect to potential interference to NGSO

systems; Interference-to-Noise ratio (I/N) is also important. In this particular case, the

received interference power densities in Boeing’s table are about equal to Iridium’s

satellite noise density numbers, i.e., I/N=0 dB (or ΔT/T=100%). This level of

interference is considerable, but Iridium has determined, based on the geographic

separation between earth stations and on other factors, including the limited duration of

the interference events, that Boeing’s proposed operations are unobjectionable.


2In discussions with Boeing, Iridium had requested that Boeing file a technical analysis and had
explained that it did not regard the certification Boeing had filed, which formed the basis for Boeing’s
Opposition, as responsive to Iridium’s concerns.


                                            -3-


       Discrepancies in the C/I ratio and other figures. Iridium does not agree with all

of the parameters and other figures used in Boeing’s Supplemental Engineering

Showing. For example, Boeing’s C/I analysis makes assumptions that the nominal

Iridium received signal at the satellite is identical to the maximum received signal.

Moreover, the analysis assumes a C/I criterion of 15 dB, but Iridium uses a C/I ratio of

19 dB. Iridium does not believe these discrepancies had a material impact on the

outcome here. Iridium wishes to make clear, however, that future applicants and

parties coordinating with Iridium should not assume that the Boeing inputs are

acceptable to Iridium.


       Cumulative effects. Boeing’s interference analysis is based on the potential for

interference presented by transmissions from a single earth station. Interference,

however, is cumulative. Iridium’s feeder links are subject to interference from various

sources, including the earth station that is the subject of the above-captioned application

and earth stations that are operated by other licensees.


       Multiple sources of interference can cumulate both in power and time. In the

case of power, main beam transmissions from gateway earth stations and/or user

terminals can be aggregated into Iridium’s satellite antenna sidelobes. In the case of

time, main beam transmissions from gateway earth stations and/or user terminals can

generate interference events that are limited in time individually but are significant in

the aggregate. Both types of cumulative interference are a concern.


                                           -4-


       Because interference is cumulative, analyses such as the one provided by Boeing

are only a starting point. In the future, Iridium may need to object to proposed

operations that are not, by themselves, predicted to cause interference to Iridium’s

feeder links, but that are predicted to cause such interference when viewed in

combination with other interference sources.


                                         Respectfully submitted,
                                         IRIDIUM SATELLITE LLC
                                         By: /s/Donna Bethea Murphy
                                         Donna Bethea Murphy
                                         Vice President, Regulatory Engineering
                                         Iridium Satellite LLC
                                         1750 Tysons Boulevard
                                         Suite 1400
                                         McLean, VA 22102
                                         (703) 287-7400

July 11, 2012


                           CERTIFICATE OF SERVICE

       I hereby certify that a true and correct copy of the foregoing REPLY OF
IRIDIUM SATELLITE LLC was sent by first class mail, postage prepaid, this 11th day
of July, 2012, to each of the following:


            The Boeing Company
            PO Box 3707
            Seattle, WA 98124-2207
            Attention: Ronald E. Center

            John E. Garcia
            The Boeing Company
            PO Box 3707
            Seattle, WA 98124-2207
            Attention: Freq Mgt Svcs, M/C 2T-22

            Bruce A. Olcott
            Squire Sanders (US) LLP
            1200 19th Street, NW
            Suite 300
            Washington, D.C. 20036



                                      /s/ Deborah Wiggins
                                         Deborah Wiggins



Document Created: 2012-07-11 14:59:39
Document Modified: 2012-07-11 14:59:39

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