Questiny Group

An NTIA Report leaked to Bloomberg Press stated that LighSquared’s basestations continue to disrupt GPS receivers.  The Bloomberg article specifically stated,  “The results from testing conducted Oct. 31 to
Nov. 4 show that “millions of fielded GPS units are not compatible” with  the planned nationwide wholesale service, according to the draft seen by Bloomberg News.   “LightSquared signals caused harmful interference  to majority of GPS receivers tested,” according to the draft prepared  for a meeting next week of U.S. officials reviewing the LightSquared  proposal. “No additional testing is required to confirm harmful
interference exists.””  The article went on to say that, “It [the Report] found that 69 of 92, or 75 percent, of receivers tested “experienced harmful interference” at the equivalent of 100 meters (109 yards) from a
LightSquared base station.”  Without a copy of the report and access to the test data, Questiny cannot comment on the validity of the claims.  However, our previous analysis shows that even the single carrier LightSquared spectrum plan would degrade the performance of GPS receivers that did not have sufficient attenuation at the LightSquared’s frequencies (1526-1536 MHz).  It appears that the NTIA’s direct testing has confirmed this situation — but this is not new news.

LightSquared stated at the conclusion of the FCC testing in June of 2011 that additional filtering would be needed, and contracted with the Javed corporation to construct external filters for such GPS units.  There has never been any dougt in our minds that such filters could be developed, and that they would provide sufficient filtering of the LightSquared signal to permit operation of the GPS units.  The issue has always been the conditions under which EXISTING GPS receivers would work WITHOUT MODIFICATION.  Thus it is also no surprise to to us that GPS users would frequently  find themselves in such conditions.  The report states taht 75% of the receivers would be impacted when within 100m (328 feet) of the base station.  This is fairly close to the basestation, and such close range only provides 76 dBm of attenuation (free-space) due to propagation leading to a received power at the GPS unit of (62 dBm-76 dB) -14 dBm — a strong signal level.  The GPS units must then filter that signal by more that 100 dB to minimize the effect of the LightSquared signal on its performance.  It is not surprising that standard commercial units have such filtering when they were likely designed assuming adjacent signal levels of -120 dBm not -14 dBm!

All of this is the backdrop to the FCC’s decision that it has to address the fact that even if LightSquared operates well within the technical limits of their license, such operation will still degrade the operation of existing GPS receivers not designed to accommodate such signals.  As for our prediction as to how this will turn out…as there are more voters with GPS units than voters with LightSquared units, Questiny has always believed that the FCC will eventually side with the GPS community, and revoke LightSquared’s license.  From there, LightSquared will likely sue the FCC for damages, and the FCC will find other spectrum for LightSquared.  All of this will likely be too late for LightSquared to achieve sufficient revenue to remain solvent, and once again, LightSquared will find itself at the brink of bankruptcy.

An article came out today announcing that LightSquared solves GPS interference with new device!  The article stated that  GPS device manufacturer Javad GNSS has come up with a device that “”The solution we’ve come up with dispels the myth that a product that eliminates  interference couldn’t be done,” Martin Harriman, executive vice president of  LightSquared’s Ecosystem Development and Satellite Business, said on a  conference call with reporters. “We did it. And it didn’t cost billions of  dollars or 10 years to do it. We did it.”  The article goes on to say, “Harriman said that through its partnership with Javad GNSS, which makes GPS  devices for such clients as the U.S. Geological Survey, has developed new  receivers that can be used to avoid interference between LTE and GPS.  Javad GNSS  has also completed designing and testing prototypes that can be adapted to work  with existing high-precision GPS devices, including those already being used in  the field.”

Am I missing something?  I thought the issue was not the inability to build new receivers, but the willingnesss of existing manufacturers and GPS users to accept retrofits and modifications to units already in the field?  Afterall this is not really a “Eureka” moment considering that LightSquared has had to 1) reduce the generation of intermodulation products by dropping the upper carriers and 2)consolidate GPS augmentation signals in that same part of their spectrum.  This latest announcement seems to be simply  a new receiver with better filtering, and that only has an effect AFTER the other two changes have been made.

After my shock that this is presented as such a “revelation”, the factis that with better filtering, the precision GPS receivers can coexist wtih LightSquared using the lower 10 MHz.  But we always knew this.  The issue for LightSquared is that this still sacrifices half of their capacity, and add the cost of retrofitting existing GPS receivers.  If anyone reads this article and believes that this solves the two-carrier LightSquared problem, please comment and let me know.

Today (June 9, 2011), FCC Chairman Julius Genachowski held a press conference stating that the FCC would protect GPS services, but that it was continuing to examine ways the two services could coexist.  As the article in Broadcast and Cable stated, “There continued to be an interference problem, they said, particularly in the upper portion of the band closest to GPS. While LightSquared’s proposal anticipates eventually using that spectrum as well, one FCC official said he did not see that happening anytime soon, and that the commission was focusing on the lower-band proposal.”  As also stated in the article, this is essentially a “proceed at your own risk” statement.  In other words, LightSquared’s business plan depends on rapid buildout of their network to derive free cash flow as soon as possible, but the FCC has essentially halted this until more testing can be completed for one-half of the spectrum for which LightSquared requested licensing and upon which they defined their business plan.  If I were an investor, this would dramatically increase my risk assessment for the LightSquared venture.

An FAA report leaked to the press concluded that the deployment of the LightSquared broadband communications system will cost the aviation community $70B and add 30 million tons of CO₂ to the atmosphere. There are really no surprises in this report. The impact to GPS receivers by signals such as LightSquared is relatively easy to predict, but the more relevant situation this report brings to light is the conflicting policies that overlay spectrum licensing. On one hand, we have a National Space Policy that says we must lead in the area of space-based navigation and timing; while on the other hand, we have a national broadband plan that states we must provide broadband access to larger segments of the U.S. Furthermore, we have spectrum policy that states that the FCC regulations that do not provide protection for manufacturers that build sub-performing receivers, and licenses spectrum users on this basis.

Spectrum fights are nothing new, but what is new are the economic stakes. Never before has the U.S. had to contend with so many dependent upon the electromagnetic spectrum. Historical spectrum management has relied on the “everyone gets their slice, and please play nice” policy. That meant that users licensed to operate within a given spectrum were granted access to that spectrum provided that they stayed within their technical requirements and did not interfere with other users (adjacent or otherwise). That policy appears to assume that there is sufficient time and capital for existing users of the spectrum to upgrade or accommodate new uses of the spectrum. However, demand for spectrum is exceeding the ability and capital to upgrade existing systems (especially when many of the existing users of this spectrum are the Government and municipalities). While I have not seen any reference to it, the FCC is dealing with a “sea change”, and not just a specific spectrum issue. I sense that the LightSquared-GPS issue, of which this Report is part, is a harbinger (pun intended) of things to come.

REPORT SUMMARY

An FAA report leaked to the press concluded that the deployment of the LightSquared broadband communications system will cost the aviation community $70B and add 30 million tons of CO₂ to the atmosphere. The Report cites the following reasons for this conclusion:

• Loss of benefits from the delayed NextGen [Next Generation Air Transport System] technologies and procedures
• Loss of existing GPS efficiency benefits
• Loss of existing GPS safety benefits
• Aircraft retrofit costs

The Report goes on to imply that the deployment of LightSquared is counter to the 2010 National Space Policy for the United States of America where “the U.S. must maintain its leadership in the services, provision, and use of global navigation satellite systems.” It stated that, “The international market for U.S. satellite navigation technology could be damaged.” Furthermore, the Report based these findings on the June 30, 2011 LightSquared proposal where LightSquared would begin operations in 2012 on the lower of their two 10 MHz carriers, and at reduced power (from that authorized by their license). Subsequently, LightSquared would begin operations on both carriers in 2014 (The report assumed that operation on both carriers would be at the reduced power levels). In addition to providing specific numbers for the economic benefit for GPS in the aviation community (or detriment of degraded GPS performance), the Report dismisses LightSquared’s proposals for mitigating GPS receiver overload through the use of in-line filters. The FAA essentially states that no such filters exist, and it would take 6-10 years to deploy them even if such filters did exist. The Report offered no conclusions on the impact of the initial LightSquared operation (operating only the single, lower carrier) other than it would impact the use of precision GPS receivers. These receivers operate in essentially the same frequency band as LightSquared so that no filtering would provide adequate mitigation.

The FAA Report was specifically requested by the Executive Office of the President’s Space-Based Positioning, Navigation and Timing Executive Committee’s National Coordination Office (PNT NCO) Director (1) to answer the following questions:

1. Summarize and quantify current and future benefits provided by use of GPS-based applications and any cost-benefit analyses
2. Summarize and quantify total sunk costs in GPS-based infrastructure (prior years to date) and planned investments going forward
3. To the extent possible, qualify, quantify and describe the risks to your agencies GPS-based mission capability, including “lost benefits” if GPS performance were degraded (or lost) due to LightSquared’s signals including the cost to modify (or replace) GPS receiver infrastructure and time frame required to replace that infrastructure.

In response to these questions, the FAA reported that GPS provides “at least $200 million in efficiency benefits” and saves 800 lives over the next 10 years ($5B of public safety benefit). However, they go on to cite that the primary benefit is through the Next Generation Air Transport (NextGen) system of $123B and reducing carbon emissions by 64 million tons by 2030. From Questiny’s perspective the impacts to NextGen, whether real or perceived, are the delay to that program. NextGen is an upgrade to the FAA air traffic control system to use precision GPS data rather than ground-based radars to locate and track aircraft. In the 1980’s the FAA attempted to upgrade the air traffic control system, and while my memory is a bit hazy on the details, I recall that that upgrade was fraught with problems and eventually cancelled. The Joint Planning and Development Office (JDPO) for NextGen estimates that “not expanding the ATC system’s capacity will be costing the U.S. economy $40 billion per year by 2020 because the overburdened system will force significant rationing of flights.” Thus, even a 2 year delay in NextGen could cost $80B to the economy.

(1) The PNT NCO was established in 2006 and its Charter states: “The Executive Committee is the senior-level federal government body established by the President’s Space-Based PNT Policy to advise and coordinate among member Departments and Agencies responsible for the strategic decisions regarding policies, architectures, requirements, and resource allocation for maintaining and improving U.S. space-based PNT infrastructure.”

The Comerce Department’s telecommunication division has released a report stating that, “LightSquared should not commence commercial services per its planned deployment for terrestrial operations in the 1525 – 1559 MHz Mobile-Satellite Service (MSS) Band due to harmful interference to GPS operations.”  Strong words from a Government Agency.  Although, this is no real news since LightSquared’s own report to the FCC reached essentially the same conclusion.  The tests were so bad that LightSquared delayed the report two weeks to have time to prepare an alternate plan where they would delay operation in the upper portions of their licensed downlink band to minimize the impacts.   We have been conducting our independent review of the technical report delivered to the FCC, but at over 1000 pages, it will take some time.  There has much “banter” back and forth in a “He said, she said” game.  In reality, the truth is somewhere in the middle.  It is true that LightSquared is meeting the technical terms of their license.  It is true that the LS downlink transmissions will impact the current generation of GPS receivers, and it is also true that the GPS industry should have known that this was coming.  But such arguments are akin to children arguing on the playground.  The “adult” in this equation is, or should have been, the FCC.  In other areas the FCC, and their big brother-the International Telecommunications Union (ITU), demands progress be made toward the implementation of systems that use the spectrum.  For example, if satellite companies don’t meet progress milestones  on time, the can lose their license for a particular satellite slot.  For this spectrum, the satellite use was taken up rapidly, but the terrestrial component, or Ancillary Terrestrial Component (ATC), has languishes for years – the very period where GPS devices found their way into mainstream America.  In my opinion, this is where the fault lies. 

As the deployment of the ATC component of this spectrum languished, the FCC could have taken steps to either remove the allocation as an MSS/ATC band, to an MSS-only spectrum, or revoke the licenses of those who did not meet their milestones.  The fact that they did not take pro-active action to avoid this problem is their failing of leadership.  Now the FCC will likely claim that they cannot adjudicate the business plans of Companies by granting and revoking licenses, but this is a false claim.  They do that all the time with other spectrum license holders.  So the FCC “dropped the ball” on this one.  So what.  Every organization has it faux pas’, but it’s the recovery that matters.  Now is the time for the FCC to take a leadership position.  They need to step in and stop the wrangling, name calling, and wanton waste of treasure from all who are seeking a solution in their favor.  In short, the FCC needs to re-allocate this spectrum.  It’s not ideal, it may not even be right, but it is necessary. 

Millions of GPS devices exist and are relied upon.  That is a fact.  These devices were not designed to accomodate high power transmissions in adjacent spectrum.  Also a fact.  LightSquared had rights to that adjacent spectrum.  Also a fact.  However, LightSquared got their too late.  It sucks to be late.  LightSquared has a legitamate claim to spectrum, and LightSquard’s desires are in line with overall policy of the current Administration and the FCC.   The FCC needs to find other spectrum that will accommodate the growth of wireless.  The market questions of bandwidth and mobility have been answered-consumers will by as much bandwidth as they can get, and they will take as much of that bandwidth on the road with them as they can.  Now the FCC needs to get on with the business at hand and develop a better National spectrum policy that provides the spectrum resources that satisfy that market.

On June 30, 2011, LightSquared™ officially submitted the final report from the Technical Working group tasked with analyzing the impact of LightSquared’s deployment on the GPS community. In addition, LightSquared™ officially recommended that they defer their immediate plans to use the upper 10 MHz of their downlink spectrum (1545.2 MHz-1555.2 MHz), and operate solely on the lower 10 MHz portion (1526 MHz – 1536 MHz). LightSquared™ cited the correct source of the impact as to the filtering in the GPS receivers allowing the LightSquared™ signals to enter and distort within the GPS receiver. LightSquared™ also correctly noted that the use of only the lower 10 MHz LTE carrier will dramatically reduce the interaction between the GPS receivers and the LightSquared™ towers. Our calculations show that the distance for a given degradation is reduced by about 5x when the upper carrier is inoperative. For example, the distance for a 2 dB receiver desensitization (i.e., reduction in C/No or Eb/No) is reduced from approximately 5 km to under 1 km in free-space (no shadowing by buildings or effects from the Earth).

Figure 1. Receiver Desensitization Distance

Figure 2 shows the impact of the reduction of the upper carrier on the intermodulation power spectral density, and it’s dramatic reduction around the 0 frequency point (the location of the L1 GPS carrier). This characterizes the impact on the GPS-only receivers; it does not address the precision GPS receivers whose front-end filters intentionally include the adjacent MSS band to receive location augmentation information over satellites (such as Inmarsat). We will examine this impact next.

Figure 2a. Single carrier intermodulation power spectral density (-61 dBm)

Figure 2b. Intermodulation power spectra for dual LightSquared carrier operation

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Most notably, in the recommendation is the GPS signal degradation employed to assess impacts. LightSquared considered a 6 dB loss in C/N0 as acceptable if the GPS receiver still functioned, whereas the GPS portion of the TWG, thought that a loss of 1 dB in C/N0 was a significant impact to the performance of the GPS receiver.  Arguments for either side can be made, and this is another area for our investigation into the technical results published today.  It should be noted that for satellite systems, the International Telecommunications Union (ITU) uses a 6% dT/T criteria which is equivalent to a 0.25 dB degradation in C/No!

The final technical report contains more than 600 pages of technical documentation and test results.  This will take some time to review.

PC World’s online news reported that the House Appropriations Committee “passed a measure that would use Congress’ control of the FCC’s purse strings to stop the agency from letting LightSquared move forward.” The article quoted the Committee as stating, “None of the funds made available in this Act may be used by the Federal Communications Commission to remove the conditions imposed on commercial terrestrial operations … until the Commission has resolved concerns of potential widespread harmful interference,” with GPS, said the text of the measure, an amendment to a funding bill. This seems to increase the pressure on LightSquared as this will likely further delay their deployment, or at least, curtail it. Given LightSquared’s desire to deploy a terrestrial system within 12-18 months, this places great pressure on their engineers to develop a system design that reconciles handset design, base station configuration, antenna design, etc. If LightSquared limits their terrestrial component to the 1 lower 10 MHz carrier in the 1500 MHz band, and are granted other slots in the AWS band (conjecture on my part) at 2100 MHz, the engineers have quite a frequency plan to resolve. This AWS frequency is 40% away from their allocated spectrum, and I believe it is upaired. This creates many issues on the selection of filters, receiver cards and base station equipment, as well as, the issue with the handsets. Engineers can be quite creative to finding solutions to all of these issues, provided their is sufficent money and budget to solve them. The engineers at LightSquared have quite a challenge ahead of them.

An article was published in the Light Reading Mobile web-site today regarding LightSquared’s interference issues with GPS receivers.  (http://www.lightreading.com/document.asp?doc_id=208849).  Essentially, the article states that the GPS community is requesting the FCC look for new spectrum for LightSquared.  This is really no surprise.  With millions of existing GPS receivers in the hands of voters, how could this really end any differently.  Forget the fact that LightSquared is technically meeting all of their regulatory requirements, or the fact that the GPS receiver manufacturers knew that the adjacent spectrum was allocated for terrestrial towers (requiring them to use better front-end filters).  This result was dictated by the GPS manufacturers building receivers that allowed energy from the frequency band adjacent to Radio Navigation band to leak into their receivers, and in the end, I suspect that millions of GPS receivers (in the hands of voters) will trump the technical ligitimacy of LightSquared.

Soon Questiny Group will publish a white paper showing our analysis of the interference between LightSquared and GPS.  Early results of that  analysis show that there is nothing that LightSquared can really do about the problem as the interference is manifested within the GPS receivers themselves.  This leaves the only option one of finding new spectrum for LightSquared-no easy task.

Another aspect adding to this drama is the financial terms LightSquared has agreed to.  As a post in by TMF Associates blog (http://tmfassociates.com/blog/2011/06/) pointed out last Friday, if LightSquared does not deploy their network soon, they default on their financial terms.  This could add to the pressure LightSquared is under to find a resolution to the interference issue (i.e., look for other spectrum).

This week we hired Nathan Saichek to help with the development of our Land-mobile SATCOM Network Simulator (LMSNS). We are delighted to have Nathan on board and look forward to kicking the development into high gear. Furthermore, we have added some of our perspective on modeling to our web-site.  Please check out the Satellite Simulation page.