Why LightSquared failed: It was science, not politics

The seeds of LightSquared's failure to win government clearance to build a 4G-LTE network can, ironically, be found in the "approval" the company received just 13 months ago.
In January 2011, the Federal Communications Commission (FCC) was clearly getting a positive vibe from LightSquared's plan to build an open-access network using both satellites and cell towers. The conditional approval issued by the agency stressed the positives of LightSquared's plan, noting that "if LightSquared successfully deploys its integrated satellite/terrestrial 4G network, it will be able to provide mobile broadband communications in areas where it is difficult or impossible to provide coverage by terrestrial base stations (such as in remote or rural areas and non-coastal maritime regions), as well as at times when coverage may be unavailable from terrestrial-based networks (such as during natural disasters)."

LightSquared chalks this up to a failure on the part of GPS makers, and this is at least partly true

The FCC detailed further "public interest benefits," such as increasing competition among mobile wireless providers, spurring innovation in the consumer device industry by providing a network not tied to any single carrier, and providing additional broadband capacity at a time "when the use of such services is increasing exponentially." The FCC would probably argue today that these needs are still just as pressing. Yet this past Tuesday the commission decided to withdraw its conditional approval.
Despite the FCC's glowing remarks about LightSquared, the conditional approval made it clear the plan would never gain final clearance unless it could be implemented without interfering with GPS devices. In a nutshell, LightSquared needed a special waiver because it is trying to use spectrum allocated for low-power space-to-ground transmissions for something it was not originally allocated for: high-power ground-only transmissions that could fuel a nationwide wireless mobile broadband network. The portion of L-Band spectrum controlled by LightSquared is adjacent to the spectrum used by GPS devices, and GPS devices, according to repeated tests, would be unable to receive the signals intended for them because the high-power LightSquared signals would overpower the GPS ones.
This doesn't mean LightSquared signals would travel outside their allotted spectrum. Rather, most GPS devices are incapable of filtering out signals from adjacent frequencies—particularly when those signals are many times stronger than the signals GPS devices are supposed to receive. LightSquared chalks this up to a failure on the part of GPS makers, and this is at least partly true. Michael Marcus, who worked at the FCC for 25 years and is now a consultant on wireless technology and spectrum policy, writes that cellular base stations have been "allowed next to the GPS band since 2003" under FCC policy, yet GPS makers "paid little attention to the fact that GPS would be having a new neighbor with much stronger signals in some places than the original MSS [mobile satellite services] signals."
Marcus, who does some consulting work for LightSquared, further writes that the "GPS industry has not pressed the filter manufacturers for the latest technology," and "as a result many GPS receivers have a lingering vulnerability to strong adjacent band signals that results from GPS manufacturers ignoring policy changes made in the US almost a decade ago."

Blame GPS makers as much as you want, but interference is still a problem

It thus seems there is good reason to criticize the GPS industry for failing to create devices that filter out signals from adjacent bands. The "Save Our GPS" industry group that opposes the LightSquared plan did not respond to an interview request from Ars this past week. But given the simple reality that most current GPS devices cannot filter out LightSquared signals, government-commissioned studies have concluded that it would be impractical to force GPS makers to retrofit all existing devices in time for the mobile network's proposed launch in 2012. If one just ignores the question of whose fault this is, the government has concluded that the GPS system is simply too important to disrupt.

"Nobody's fault but mine"

Devices connecting to the LightSquared network would have two chips, one to connect to cell towers and another to connect to satellites. The spectrum that would be used for the ground towers is spectrum originally allocated for satellite-to-ground transmissions. LightSquared's initial plan called for 40,000 cellular base stations across the US.

LightSquared: Spectrum reallocation drives innovation

"Lots of spectrum is allocated to one thing and it evolves into something else. For instance, broadcast spectrum has been reallocated for wireless use," argued LightSquared spokesman Chris Stern in an interview with Ars. "The cell phone spectrum I'm talking on now was originally allocated for something else. Changing allocation is something that not only has happened for decades, but it is something that is really important for the evolution of technology."
Still, the FCC has discretion over how spectrum is allotted and can—as it ultimately did in this case—decide that certain slices of spectrum aren't suitable for a particular use.
Ideally, Marcus tells Ars, the FCC and NTIA "could have adopted a set of power flux density limits on LightSquared that would have protected all the safety-related uses of GPS and most of the non-safety related uses," with a gradual relaxation of limits as GPS technology improved to prevent interference. "However, due to resource and structural problems at FCC and NTIA this was not really feasible," he said.
LightSquared cell tower signals would be far stronger than the signals GPS devices must receive from space, but Stern says that's not the problem. For one thing, he said, LightSquared agreed to reduce its power levels by a factor of 32 after its initial plan raised a huge outcry from the GPS industry. For another, he says, "GPS devices are designed to look into spectrum that is licensed to LightSquared. That's the problem.... The commercial GPS folks... viewed the LightSquared spectrum as a vacant lot that nobody would use and they could use. It was sort of like if you lived in a subdivision and no one built in the lot next door to yours, and one day you're like 'I'm going to build my patio out into their lot,' and then one day somebody buys the lot next door to you and plans to move in and you say 'you can't move in there because I have my patio on your lot.'"

It's your fault for being able to hear stuff

Matthijs

If GPS makers were to make a similar analogy, it might be that LightSquared's proposed cell towers are more like a loud neighbor. If you live in an apartment building and can't hear the sound of your own voice because the neighbors blast heavy metal music at ear-shattering levels 24 hours a day, it's not your fault for having ears that are capable of detecting sounds from ten feet away. The neighbors might be creating the noise within their own walls, but it's still loud enough to drown out the sounds made by the people next door.

LightSquared's conditional approval contained the seeds of its demise

We know of no currently available receiver, filter, antenna or other mitigation technology that would enable the construction of LightSquared's proposed network without interference

While the FCC's decision last week may seem like backtracking at a cursory glance, its January 2011 approval of LightSquared's waiver request made it conditional on LightSquared creating a joint working group with the GPS industry to examine potential interference, and said the network could not be built unless the GPS concerns were completely assuaged.
LightSquared's request for a waiver was "granted in part and denied in part," with the FCC saying "LightSquared may commence offering commercial service on its MSS L-band frequencies under the authority granted herein only upon the completion of the process for addressing interference concerns relating to GPS."
Since then, government testing initiated because of the process set in motion by the FCC has found that LightSquared's proposed plan would interfere with the operations of most GPS devices. The studies' conclusions make it seem—in hindsight—that LightSquared's attempt to re-purpose spectrum originally allotted for satellite communications was doomed from the start. As if confirming the unsuitability of LightSquared's spectrum for a ground-based network, billionaire owner Phil Falcone is now reportedly seeking to trade spectrum with the US Department of Defense in order to acquire more viable spectrum.
The GPS industry was already piping up during the process that led to LightSquared's conditional approval. An FCC statement this week noted that "Late in 2010, during the waiver proceeding on requirements for mobile devices, the GPS community had raised for the first time concerns that LightSquared’s terrestrial base stations (that is, its cell towers) would cause widespread overload interference to GPS receivers and other GPS devices."
An independent assessment released in June at the behest of the National Telecommunications and Information Administration (NTIA) contains a recommendation that the FCC "rule that LightSquared cannot 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." The testing, conducted by the National Space-Based Positioning, Navigation, and Timing Systems Engineering Forum (NPEF) found "significant detrimental impacts to all GPS applications." Another report in June by a "Technical Working Group" with representatives from LightSquared and the GPS industry presented conclusions from both sides.
The GPS industry representatives stated in the joint report that "We know of no currently available receiver, filter, antenna or other mitigation technology that would enable" the construction of LightSquared's proposed network without interference, and said "the most straightforward mitigation would be for LightSquared to use a different frequency band for their terrestrial network." Tests conducted by the Technical Working Group in Las Vegas found that "the interfering signal at a distance of 500 feet from the [cell] tower [was] up to 800 billion times more powerful than the distant GPS signals being received from space," according to Save Our GPS, and that even a mile from the tower the power levels were "400 million times those of the GPS signals."
LightSquared's conclusions spelled out in the report were that GPS receivers "are designed in such a way that they may receive harmful interference due to receiver overload from the LightSquared Base Station 4G LTE signals operating in an adjacent band," but that "mitigation is feasible."
To appease the GPS industry, LightSquared said it would lower the power levels and "forego providing service using the 10 MHz band closest to GPS frequencies for a few years and instead … launch service using a lower 10 MHz band that is farther away from GPS," claiming that this would prevent any problems for the vast majority of GPS devices.
Yet a further round of tests taking into account LightSquared's modifications showed interference in 69 of 92 GPS receivers, or 75 percent. "Mitigations have been proposed, they have not been tested and verified to have no impact on GPS receiver performance and the Position, Velocity, and Timing (PVT) applications for which they are used," the updated NPEF report said. "If and when mitigations are available, a long term transition and implementation plan would be necessary to protect existing GPS services and users." Retrofits and upgrades would take "a minimum of 10-15 years to implement" for the military and the Federal Aviation Administration's project to upgrade its navigation system using GPS.

Controversy ensues

Along the way, there was plenty of politics, with GPS industry representatives saying LightSquared proposed to "defy the law of physics," and LightSquared asking the FCC for a declaratory ruling stating that it has the right to use its spectrum as it wants to, and that GPS device makers lack any legal basis to ask for interference protections. LightSquared also asked the FCC to impose new regulations on GPS devices to prevent them from receiving interference from neighboring spectrum.
"The two sides," Marcus said, "have become like the Democrats and Republicans, or the pro-life and pro-choice people, or the Arabs and the Israelis, each one posturing for their position and unwilling to search for common ground."

It appears LightSquared's 4G aspiration has hit a wall that it cannot scale. GPS devices, and all the ordinary people and critical industries that depend upon them, are still safe

In the end, though, it was not politics, but the results of repeated tests which the FCC could not ignore, and thus doomed LightSquared. The ruling against the company seems to be grounded in science and common sense, coming swiftly after the NTIA reported to the FCC that months of analysis determined that "LightSquared's proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time. Furthermore, while GPS equipment developers may be able to mitigate these issues via new technology in the future, the time and money required for federal, commercial, and private sector users to replace technology in the field and the marketplace, on aircraft, and in integrated national security systems cannot support the scheduled deployment of terrestrial services proposed by LightSquared." The NTIA further noted potential problems for air traffic navigation and NASA's "future space-based GPS receivers" that would be sensitive even to LightSquared's usage of signals in the lower 10MHz.
Even if one assigns the blame to the GPS industry for not preventing interference, the FCC had to make a decision based on the reality of today's devices. The problem simply cannot be wished away overnight, and the FCC concluded that GPS technology is too important to mess with—even for something as potentially useful as LightSquared's proposed network.
If a compromise was possible, it was made difficult by the extreme positions taken by both sides, and that, in Marcus's view, "the FCC and NTIA don't have the tools to do their jobs. It's not an issue of politics. Politics has complicated it, but it's a complex issue and the people involved don't want to roll up their sleeves and search for a solution." The case, he said, "needed an untraditional decision," but the FCC is "busy treating it traditionally."

What's next?

On Wednesday, the FCC kicked off a public comment period which will last until March 1. LightSquared has already responded to the public notice, saying "We remain committed to finding a solution and believe that if all the parties have that same level of commitment, a solution can be found." But given the weight the FCC has put on the GPS interference research, it seems unlikely LightSquared will be able to change the agency's mind.
LightSquared could, as noted above, seek to swap spectrum in order to find a band more suitable for its proposed use. But that could open up a new regulatory process that would likely be costly, lengthy, and complicated, just as the current process has been. LightSquared is reportedly exploring potential lawsuits against both the FCC and against GPS industry members for failing to create devices that filter out signals from adjacent spectrum. But there are reports LightSquared may run out of money before the year is up, despite the fact that Sprint will have to return $65 million to LightSquared it had received as part of a network-sharing deal.
Stern, the LightSquared spokesperson, tells Ars that the company is still committed to "push for its rights to use this spectrum." Finding other spectrum is a possibility, however, he said. LightSquared does have a revenue stream from the satellite service it has been operating for the past 12 years, and has enough money to "continue operating for the next several quarters," he noted.
But for now, it appears LightSquared's 4G aspiration has hit a wall that it cannot scale. GPS devices, and all the ordinary people and critical industries that depend upon them, are still safe.
Stern contends that one of the "most important legacies of LightSquared" is its push for new standards to ensure that GPS receivers don't pick up signals from adjacent spectrum. Marcus tells Ars that the problems in GPS that LightSquared "made visible are quite real and will impact other bands unless FCC and NTIA and Congress address them."
But given the time needed to set standards for new devices and overhaul the GPS devices already on the market, any such change would come too late to salvage LightSquared's plan. Sprint, for example, has said it is only willing to wait until mid-March before pulling the plug on its partnership with the satellite company. LightSquared's idea of using both satellite and cell tower signals to expand mobile broadband coverage across the nation—a good idea, if not for all that inconvenient GPS interference stuff—is dead for now.