*Pages 1--15 from Microsoft Word - 24939.doc* Federal Communications Commission FCC 02- 324 Before the Federal Communications Commission Washington, D. C. 20554 In the matter of AIRCELL, INC. Petition, Pursuant to Section 7 of the Act, for a Waiver of the Airborne Cellular Rule, or, in the Alternative, for a Declaratory Ruling ) ) ) ) ) ) ) ) ) ORDER ON REMAND Adopted: November 26, 2002 Released: February 10, 2003 By the Commission: Commissioner Martin concurring and issuing a statement; Commissioner Abernathy not participating. A. Introduction and Summary 1. This Order on Remand completes our review of several orders by the Wireless Telecommunications Bureau (Bureau) granting to AirCell, Inc. and its cellular licensee partners (collectively, AirCell) waivers of section 22.925 of the Commission’s rules. 1 The waivers enable AirCell subscribers to operate, under the authority of AirCell’s partners’ cellular licenses and on a secondary non- interference basis, specially designed cellular telephones in airborne aircraft, which section 22.925 would otherwise prohibit. After the Commission affirmed the Bureau’s orders in a Memorandum Opinion and Order in this proceeding (AirCell MO& O), 2 a number of cellular carriers appealed the AirCell MO& O to the United States Court of Appeals for the District of Columbia Circuit (the Court). 3 On November 9, 2001, the Court substantially affirmed the AirCell MO& O. However, the Court remanded the matter to the Commission for a fuller explanation of one technical aspect of the Commission’s decision. 4 After denying a subsequent request by the appellants for rehearing, the Court issued its mandate on January 29, 2002. In this Order on Remand, we reaffirm our conclusion that 1 47 C. F. R. § 22. 925. 2 See, In the matter of AirCell, Inc., Petition, Pursuant to Section 7 of the Act, for a Waiver of the Airborne Cellular Rule, or, in the Alternative, for a Declaratory Ruling, Order, 14 FCC Rcd. 806 (WTB 1998) (AirCell Bureau Order), reconsideration granted in part, denied in part, Order on Reconsideration, 14 FCC Rcd. 19430 (WTB 1999) (AirCell Reconsideration Order), application for review denied, Memorandum Opinion and Order, 15 FCC Rcd. 9622 (2000) (AirCell MO& O). 3 The parties who petitioned for reconsideration of the waiver were: AirTouch Communications, Inc., Ameritech, AT& T Wireless Services, Inc., Bell Atlantic Mobile, BellSouth Cellular Corp, GTE Wireless Inc., and SBC Wireless, Inc. By the time the court appeal was filed, a number of these entities had combined, such that the appellants in this proceeding were AT& T Wireless Services, Inc., BellSouth Cellular Corp, SBC Wireless, Inc., and Cellco Partnership (dba Verizon Wireless). Since that time, BellSouth Cellular Corp and SBC Wireless, Inc. have become Cingular Wireless. 4 AT& T Wireless Services, Inc., et al., v. FCC, 270 F. 3d 959, 968 (D. C. Cir. 2001). 1 Federal Communications Commission FCC 02- 324 2 operation of the AirCell system is not likely to cause harmful interference to terrestrial cellular systems and provide a more complete explanation for that conclusion. We therefore reaffirm the Bureau’s waivers. 5 2. The main issue regarding which the Court instructed the Commission to provide fuller explanation concerns a technical benchmark we called the “interference threshold level” (ITL). 6 As used in this proceeding, for a given environment, the ITL is the highest level of noise and interference power that can be received by a cellular base station receiver without any interference being caused to the weakest telephone call that could still be considered an acceptable quality call. 7 In this case, parties on both sides of the proceeding submitted ITL calculations as part of their technical arguments regarding the likelihood of the AirCell system causing harmful interference. The Commission considered these submissions and also calculated our own ITL. We then used our ITL to help us evaluate whether an AirCell airborne mobile telephone transmission received as an unwanted signal by a non- affiliated cellular base station would be powerful enough to affect the quality of terrestrial cellular calls in any meaningful way. As discussed below, we based our ITL calculations on technical parameters that are generally accepted in the industry and are well within the range of values in the record. Indeed, our calculated ITL matched not only that presented by supporters of the AirCell system, but also the value put forth by AT& T Wireless, one of the appellants. The Court, however, concluded that the Commission had not adequately explained its rejection of a lower ITL advocated by another of the appellants, AirTouch. To address the Court’s concern, we further explain below that we rejected the AirTouch ITL calculation because it was based on technical assumptions more conservative than the industry consensus, did not take into account the received power level of typical cellular telephone calls, and was marred by a mathematical error. 3. The Court also instructed the Commission to explain how it reached its conclusion without assessing the probability of AirCell and a terrestrial carrier using the same frequency in the same area simultaneously, which could affect the likelihood of harmful interference. As explained below, in reaching its conclusion that the AirCell system is not likely to cause harmful interference, the Commission did not factor in any probability evidence because the Commission concluded that, even if these events were to occur simultaneously, the AirCell system would not cause harmful interference to terrestrial cellular networks because of that system’s built- in safeguards. 8 As a result, the Commission did not need to consider probability evidence in order to extrapolate from the test data in the record. B. Background 4. Section 22.925 of the Commission’s rules (the airborne cellular rule) prohibits the operation of cellular telephones while airborne. The Commission adopted this rule because of the potential for 5 Following the Court’s remand of the AirCell MO& O, the Commission and its staff have received correspondence and pleadings from various parties to the proceeding. As we neither solicited nor granted leave to file additional pleadings in this docket, we need not consider them here. The record compiled in the underlying proceeding was a sufficiently adequate base on which to rest the Commission’s decision, and as this Order on Remand merely explains that decision in greater detail on the basis of that record, we need only look to that record. 6 AirTouch and the appellants refer to this as the “interference tolerance level.” 7 As explained below (see ¶ 22), although a noise and interference power level slightly above the ITL indicates the possibility of some degradation to the desired signal, it must be substantially above the ITL in order to cause harmful interference, which a secondary service (such as AirCell’s) is not permitted to cause to a primary service (such as the appellants’). 8 The AirCell system incorporates a number of safeguards, such as dynamic power control, to prevent harmful interference. In addition, the waiver requires that AirCell maintain a central control point and shut down the system immediately if monitoring shows a malfunction or other event likely to cause harmful interference. AirCell Bureau Order at Appendix A. 2 Federal Communications Commission FCC 02- 324 3 harmful interference to terrestrial cellular networks when a wireless telephone is able to transmit to a large number of base stations simultaneously, as is the case when that telephone is airborne. 9 Such an effect is made possible by the architecture of a cellular system, which is based on re- use of frequencies. Section 22.925 was designed to address the particular circumstance of airborne use of a mobile phone with sufficient power to reach multiple base stations in this manner. Apart from this prohibition, our rules explicitly provide that cellular base station receivers are not afforded any protection against interference from mobile units. 10 5. AirCell developed a system of specially designed telephones and ground equipment that allows users to access the existing networks of cellular licensees with whom AirCell has partnered without causing such interference. Because AirCell’s partners’ ground stations are located in rural areas, where ambient RF noise levels are lower, AirCell’s specially designed customer end equipment can operate at very low power and still maintain reliable communications with the ground stations. 11 AirCell also employs special, horizontally polarized antennas which further reduce the potential for harmful interference with the vertically polarized antennas commonly used in terrestrial base stations. Additional measures to prevent interference include dynamic power control, a single command point at which the system can be shut down, and frequency coordination with non- participating carriers. 12 AirCell’s partner licensees operate the system on a secondary basis with ground equipment co- located at their base stations. Traffic from AirCell’s airborne terminals is handled through these partners’ facilities. 6. On October 9, 1997, after conducting operations pursuant to an experimental license, 13 AirCell filed a petition for waiver with the Bureau in order to deploy its system commercially, 14 to which a number of cellular carriers filed oppositions. 15 As part of the pleadings submitted to the Bureau, both AirCell and its cellular carrier opponents cited data from two days of operational tests that had been conducted jointly by AirCell and the opposing carriers in July 1997 at sites in Texas and Oklahoma to assess how the AirCell system would perform in a real- world environment. The first day of testing, on July 10, 1997, was conducted with all of the built- in safeguards in the AirCell system operating normally, while on the second day, July 11, 1997, certain of these safeguards were deliberately disabled and abnormal flights patterns were introduced into the test protocol. On September 22, 1998, the 9 See, Airborne Use of Cellular Telephones and the Use of Cell Enhancers in the Domestic Public Cellular Radio Service, CC Docket 88- 411, 7 FCC Rcd. 23 (1991). 10 47 C. F. R. § 22. 352( c)( 3). 11 This principle is analogous to being able to hear a whispered conversation from across a quiet room, while even a louder conversation might not be intelligible from a few tables away in a noisy restaurant. 12 Dynamic power control allows the system to adjust the power continuously so that only the minimum output required is used. By having a single command point, AirCell is quickly able to shut off any transmissions that are deemed to be causing harmful interference, should that occur. 13 AirCell initially began testing the concept for airborne cellular service in 1992 under the authority of various Experimental (Part 5) and Special Temporary Authorizations, and has continued refining its hardware product to the present time. See Call Sign KS2XAT: Experimental Special Temporary Authorization, File No. S-1246- EX- 92 (December 15, 1992). See also Call Sign KI2XCS: Experimental Radio Station Construction Permit and License, File No. 4555- EX- PL- 94 (December 28, 1994); Experimental Special Temporary Authorization, File No. S- 2374- EX- 96 (March 22, 1996); Experimental Radio Station Construction Permit and License, File No. 5349- EX- MR- 96 (June 22, 1996); Experimental Radio Station Construction Permit and License, File No. 5349- EX- RR- 1998 (Jan. 3, 2002). 14 AirCell, Petition, Pursuant to Section 7 of the Act, for a Waiver of the Airborne Cellular Rule, or, in the Alternative, for a Declaratory Ruling, filed October 7, 1997 (AirCell waiver petition). 15 See n. 3. 3 Federal Communications Commission FCC 02- 324 4 opposing carriers conducted a further test without AirCell’s participation at a site in Florida, which they contended showed a high potential for harmful interference. 7. On December 24, 1998, after reviewing all the test data, the Bureau granted a limited waiver of section 22.925 to AirCell and its partners for a period of two years. 16 The Bureau concluded that the test results demonstrated that the AirCell system would not cause harmful interference to cellular operations under normal operating conditions. In reaching this conclusion, the Bureau did not give significant weight to test data that assumed abnormal flight conditions and the disabling of those parts of the AirCell system whose express purpose was to prevent such interference. 17 The Bureau also imposed limitations on the operation of the AirCell system to protect further against the risk of interference. Specifically, the waiver provided that airborne service could be provided only on a secondary basis to regular cellular communications, requiring the AirCell system to cease operations immediately if harmful interference occurred. 18 The Bureau also restricted operation of the AirCell system to six channel pairs per ground station, required the use of non- standard control channels, and required advance notice to and coordination with non- participating cellular carriers within 270 kilometers of any AirCell operations. 19 8. The opposing carriers filed a Motion for Stay and Petition for Reconsideration of the Bureau waiver order, and AirCell filed a petition for reconsideration of the 270- kilometer notification requirement. The Bureau subsequently granted AirCell’s petition and reduced the notification requirement to 151 kilometers, 20 and expanded the waiver to include additional partner carriers. 21 Over the following thirteen months, the opposing carriers filed additional Applications for Review and Motions for Stay of the various Bureau orders. These pleadings, as well as a Petition for Clarification filed by TruePosition, Inc and Applications for Review of certain letter rulings issued by the Office of Engineering and Technology (OET), were consolidated and addressed by the Commission in the AirCell MO& O, which affirmed these Bureau orders and the OET letter rulings. 22 9. In the AirCell MO& O, the Commission extensively reviewed the data from the tests conducted on July 10- 11, 1997 and September 22, 1998 that had been previously reviewed by the Bureau. 23 In upholding the Bureau decision, the Commission specifically rejected the data from the July 11 and September 22 tests, upon which the appellants relied, as unreliable and based on unrealistic test 16 AirCell Bureau Order. 17 AirCell MO& O at ¶19. 18 A secondary service may cause no interference, must cease operation if it cannot fix any interference problem that arises, and must accept interference from the primary service (in AirCell’s case, the terrestrial cellular licensees). 19 AirCell Bureau Order at Appendix A. 20 AirCell Reconsideration Order at ¶¶ 12- 16. 21 AirCell, Inc., Pine Belt Cellular, Inc. Tennessee RSA No. 3 Limited Partnership, WESTEX Telecommunications, Inc., XIT Cellular, ETEX Cellular Co. Inc., Cellular Network Partnership, and North Alabama Cellular, LLC, Petitions for Waiver of the Airborne Cellular Rule, 14 FCC Rcd. 13151 (WTB 1999); AirCell, Inc., ALLTEL Communications, Inc., American Rural Cellular, Inc., Centennial Cellular Corporation, CenturyTel Wireless, Inc., Kentucky RSA 4 Cellular General Partnership, and Smith Bagley, Inc. d/ b/ a/ Cellular One of Northeast Arizona, Petitions for Waiver of the Airborne Cellular Rule, 15 FCC Rcd 1639 (WTB 1999). 22 The Commission’s affirmation of the OET letter rulings is not at issue on remand. 23 See AirCell MO& O at ¶ 20. 4 Federal Communications Commission FCC 02- 324 5 conditions. 24 The Commission further found that the data from the July 10 test supported the Bureau’s conclusion that operation of the AirCell system is not likely to cause harmful interference to terrestrial cellular systems. In its analysis, the Commission rejected an interference analysis prepared by Dr. William C. Y. Lee on behalf of AirTouch – which purported to show that the AirCell system would cause harmful interference to an underlying cellular system over 30 percent of the time – as based on unrealistic assumptions, including the use of an unreasonably low interference threshold. 25 10. On November 9, 2001, the United States Court of Appeals for the D. C. Circuit generally affirmed the AirCell MO& O, including its rejection of the July 11, 1997 and September 22, 1998 test data. 26 These data, therefore, are not matter for consideration in the instant order. As discussed above, however, the Court remanded the matter to the Commission for fuller explanation of the Commission’s interpretation of the July 10, 1997 test data. 27 Specifically, the Court found that, in concluding that these data indicated that the AirCell system was not likely to cause harmful interference, the Commission failed to provide a reasoned justification for its use of a particular interference threshold level and its rejection of Dr. Lee’s analysis. The Court also instructed the Commission to explain how it reached its conclusion that the AirCell system would not cause harmful interference without undertaking a probability study of the likelihood of simultaneous AirCell and cellular operations on the same channel in the same vicinity. 11. In limiting its remand to these narrow issues, the Court rejected the bulk of the opposing carriers’ arguments. The opposing carriers had argued that, in granting the waiver, the Commission had unlawfully modified licenses held by the opposing carriers, and that, under the Communications Act of 1934, 28 AirCell must be required to apply for a license to provide a new service. The Court found no merit in either argument, holding that the waiver grant was consistent with the licensing scheme set forth in the Act as well as the Commission’s rules. The Court similarly rejected the opposing carriers’ argument that the Commission acted in an arbitrary and capricious manner in granting the waiver. As the Court noted, the Commission was entirely within its discretion to grant a waiver of its own rule if, as it found, such a waiver would not frustrate the purpose of the underlying rule and would be in the public interest. 29 C. Discussion 12. Use of an ITL to evaluate interference potential. A central issue in this proceeding is whether the record indicates that airborne operation of the specially- designed cellular telephones supplied by AirCell to its subscribers is likely to cause harmful interference to terrestrial cellular telephone calls. 30 In addressing this issue, a majority of the parties to this proceeding, including AirCell 24 In addition, the Bureau deemed the September 22 test to be unreliable because of numerous operational flaws. For example, the test employed the wrong type of antenna, and the opposing carriers failed to record the power output of the airborne unit. Id. 25 Id. at ¶ 21. 26 AT& T Wireless Services, Inc., et al., v. FCC, 270 F. 3d at 967 (D. C. Cir. 2001). 27 Id. at 968. 28 See, 47 U. S. C. §§ 301, 316. 29 270 F. 3d. at 964. 30 Section 22.925 of the Commission’s Rules, waived for AirCell and its partners in this proceeding, generally prohibits airborne operation of cellular telephones in order to prevent possible harmful interference to cellular communications on the ground. This potential for harmful interference arises because a signal transmitted from an airborne cellular telephone covers a very wide geographic area on the ground, and could therefore be received not only by the cell site serving it, but also by numerous cell sites re- using the same channel at some considerable distance away. By contrast, the transmissions of a cellular telephone on the ground are normally received only by (continued....) 5 Federal Communications Commission FCC 02- 324 13 27. The use of a probability study. In the last paragraph of its opinion, the Court stated that it was unable to discern how the Commission could reach a conclusion on the question of harmful interference in the absence of a probability study. 68 Indeed, during the course of the proceeding, AirCell submitted two papers into the record containing assessments as to the likelihood of interference based on probability factors rather than analysis of the measured AirCell signal power levels alone. 69 Both of these papers contained concurrency calculations whose apparent purpose was to demonstrate that the probability of a simultaneous occurrence of all of the events necessary for interference from AirCell is extremely low. Appellants argued that these probability analyses comprised a major part of AirCell’s non- interference claim, and speculated that, if the Commission did not take these probability studies into account, it may have factored in some undisclosed probability study of its own devising. 70 28. The Commission does not dispute the proposition that simultaneous use in a rural area of any given cellular channel by both an airborne AirCell caller and a terrestrial caller is likely to be a relatively infrequent event. In reaching its decision, however, the Commission did not need to rely on any assessment of the probability of such simultaneous channel use. Instead, the Commission chose to use a “Murphy’s law” approach, that is, it assumed that such simultaneous channel use, albeit unlikely, would occur, and considered what the consequence of such an occurrence would be, based on analysis of the measured received power of the AirCell signal. 71 Given our conclusion that harmful interference would not result even in such a worst- case scenario, there was no need for the Commission to engage in any event probability analysis of the test data in the record. D. Conclusion and Ordering Clause 29. The Court remanded the AirCell MO& O to the Commission to explain our reasoning with regard to one technical issue, i. e. the use of a particular ITL in concluding that the AirCell system is not likely to cause harmful interference to terrestrial cellular systems. As demonstrated above, the Commission calculated its ITL from technical values that are commonly accepted by industry, and its ITL matches values used by both proponents and opponents of AirCell in this proceeding. By contrast, the ITL proposed by AirTouch was based on unduly conservative assumptions, was inconsistent with analysis presented in Dr. Lee’s own textbook, and incorporated a significant mathematical error. Moreover, because AirTouch conflated the concepts of “interference” and “harmful interference,” even if AirTouch’s analysis had been based on reasonable assumptions and accurate calculations, it would not have supported the conclusion advanced by AirTouch as to the probability that the AirCell system would cause harmful interference to terrestrial cellular systems. Finally, because the Commission assumed, in a (... continued from previous page) of –120 dBm, but with the 2 dB adjustment that value exceeds the ITL by only 1.61 dB, an amount insufficient to cause harmful interference. 68 270 F. 3d at 968. 69 See “AirCell Test Results and Implications,” John R. Doner, September 20, 1997, at 8- 18. See also “Evaluation of the AirCell Test Plan and Data Collected on July 10, 1997,” Roger D. Madden, October 1, 1997, at 23- 24. 70 This speculation was without foundation. In taking its decision, the Commission did not rely upon any calculation of the likelihood of simultaneous occurrence of conditions necessary for an interference scenario. 71 AirCell MO& O at n. 60. The “worst case” is one in which the AirCell- equipped airplane is at maximum distance from an AirCell partner site and is located directly above a “victim” site. In this configuration, the AirCell system is transmitting at its maximum designed power, and the system is located maximally close to the “victim” site. The Commission found that, even in this configuration, AirCell operation was not likely to cause harmful interference to the terrestrial cellular operation because of the design of the AirCell system, including the use of low power levels and the downward “null” cast directly below the plane by its antenna design and placement. Id. at n. 63. 13 Federal Communications Commission FCC 02- 324 14 worst- case scenario, that certain events would occur simultaneously during operation of the AirCell system – and nevertheless found that operation of the AirCell system is not likely to cause harmful interference to terrestrial cellular systems – the Commission did not need to factor in studies of the probability that those events would in fact occur simultaneously. 30. ACCORDINGLY, IT IS ORDERED that, pursuant to section 4( i) of the Communications Act of 1934, 47 U. S. C. §154( i), and for the reasons contained in the AirCell MO& O and expanded upon herein, the decision of the Commission in the AirCell MO& O IS AFFIRMED. FEDERAL COMMUNICATIONS COMMISSION Marlene H. Dortch, Secretary. 14 Federal Communications Commission FCC 02- 324 15 SEPARATE STATEMENT OF COMMISSIONER KEVIN J. MARTIN, CONCURRING Re: AirCell, Inc., Petition, Pursuant to Section 7 of the Act, for a Waiver of the Airborne Cellular Rule, or, in the Alternative, for a Declaratory Ruling, Order on Remand I write separately – and concur in this item – because I am concerned with the manner in which the Commission analyzes harmful interference. The Commission has not developed a consistent methodology for such analyses, instead using a case- by- case, ad hoc approach. Not only does this approach cause a great deal of uncertainty for spectrum users and markets alike, it also creates another problem: the appearance of results- oriented decisionmaking. Too often, a person reading a Commission order could be left with the impression that the Commission first makes a decision on whether to license some new technology and then creates a justification post hoc by manipulating the way it judges harmful interference. In this Order, for example, the Commission chose an interference threshold level of -117 dBm from a range of permissible choices after all testing had been conducted. This threshold level just happened to work perfectly when applied to the limited set of test data that the Commission retained (the Commission rejected the remaining test data). While I in no way wish to suggest that the Commission did, in fact, manipulate its methodology in order to achieve a desired result, there is a real risk that someone reading this item might be left with that impression. The Commission’s recent Order on Multichannel Video Distribution and Data Service (MVDDS) suffers from the same problem. See Amendment of Parts 2 and 25 of the Commission’s Rules To Permit Operation of NGSO FSS Systems Co- Frequency with GSO and Terrestrial Systems in the Ku- Band Frequency Range, Memorandum Opinion and Order and Second Report and Order, ET Docket No. 98- 206, RM- 9147, RM 9245 (rel. May 23, 2002). There, the Commission seemed determined to license MVDDS, adopting interference standards that assured that conclusion. In the Commission’s process of analyzing the degree of interference MVDDS would cause, the definition of harmful interference appeared to change, yet consistently allowed for MVDDS operation. In the end, as I noted in my separate statement on that Order, the interference rules the Commission ultimately adopted appeared completely arbitrary. See id., Statement of Commissioner Kevin J. Martin, Dissenting in Part and Approving in Part. Among other things, the Order set EPFD levels that were not keyed to guaranty any specific level of interference protection and that would allow an increase in interference to DBS of more than 30 percent in some instances. See id. An objective person reading this Order could reasonably conclude that the Commission was determined to allow MVDDS to share DBS spectrum and developed interference rules to support that decision. Orders such as these not only exacerbate regulatory uncertainty, they risk undermining public confidence in the Commission’s work. We can and should do better. At the very least, we should develop a consistent framework for judging harmful interference. In particular, we should adopt a policy of identifying what degree of interference will be considered harmful prior to conducting engineering tests of how much interference a new service causes. 15