Why You Should Regret LightSquared's Setbacks

from the competition-is-good dept

LightSquared is a new wireless carrier that has been trying to launch a wholesale 4G network across the USA. Funded by private equity firm Harbinger Capital, it sought to re-purpose satellite communication frequencies to build a nationwide cellular-satellite hybrid network, and then re-sell the network capacity to other brands. In January 2011, the FCC, eager to foster new competitors in the mobile space, gave LightSquared the green light to launch using their spectrum with one provision - that their network equipment NOT interfere with GPS signals and devices. Well, over a year has come and gone, and despite incredible effort and wrangling, the independent testing keeps indicating that LightSquared's terrestrial towers are not compatible with GPS device use. As such, the FCC has basically rescinded LightSquared's request to launch service on their 1.5GHz L-Band spectrum.

Note that, while LightSquared DID knock out GPS devices, it was not LightSquared that transmitted on the GPS frequencies, but rather the GPS devices that sloppily "listen" to the adjacent LightSquared frequencies. The GPS chipsets were generally cheaply made with inadequate filtering. That said, who is at fault is irrelevant: it remains LightSquared's problem to solve if they want to launch their network. A long history of spectrum policy states that new entrants must not mess up the existing radio devices.

What we've lost here is the chance to have a truly innovative wireless carrier which would have stimulated competition, energized the vendor community, and provided a white-label network for MVNOs. LightSquared had, in fact, signed up dozens of partners who would offer LTE wireless services as cellular companies, CE makers, and store brands like Best Buy, for example, who could sell connectivity in a bundle with laptops. Maisie Ramsay over at Wireless Week explains how a vast community of over 30 technology vendors have also lost a valuable path to market.

What strikes me, as someone who works with wireless carriers (LightSquared included), is that we may lose one of the scrappiest players out there. And markets thrive when a scrappy player stirs up the pot. Hutchison Whampoa stirred up the UK markets when it launched 3G in 2003, Free is currently doing the same in France. In the USA, we have regional players like Metro PCS, but nothing at the national level. My role at the Telecom Council of Silicon Valley is right where innovators meet with the telcos, and it was gratifying to see the tornado of new ideas, vendors, and possibilities that came about with a new network. Without legacy systems nor legacy thinking, lots of great ideas are free to emerge.

For now, with LightSquared's options dwindling, we may have to have to look elsewhere for new competition and open creativity. The WiFi space is fairly promising, as the spread of hotspots continues to soar, and new versions (802.11ac) promise greater range and throughput. Chipsets are cheap, and billions of WiFi devices have been produced. Republic Wireless exemplifies the possibilities of leveraging WiFi in mobile phones to the limit. Lots of people are hoping that the "white spaces" frequencies in between TV channels will be offered up to a WiFi variant, which will mean low-frequency spectrum that penetrates walls and buildings much better than today's WiFi. I like what the US carriers have done with the (globally) early launch of LTE, but there's no doubt that with increased competition we'd have a more dynamic market.

Filed Under: competition, gps, interference, spectrum, wifi, wireless
Companies: lightsquared

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  1. identicon
    Joe, 20 Feb 2012 @ 10:02pm

    Limits ofsignal filtering

    The technical results of how lightsquared interferes are doubly telling. Especially when you view it from a designer of 15 to 20 years ago.

    A) There are fundamental limits on how well an analog filter can work. 15 to 20 years ago, these *analog* limits were much more limiting, compared to today's *digital* filters. B) There are also fundamental limits on how well one can receive a doppler shifted signal if you don't know what the shift is. Some modern devices can "cheat" by using a nationwide radio network (aka the cell phone network) to get up-to-the-minute status updates; 15 to 20 years ago this was unimaginable.

    Further, the devices that worked well in the lightsquared tests (the 25% they like to crow about working) are the devices that a) were relatively new cell-phone devices, which have high-performance digital filters with much better "roll-off" than even the best analog filters, and b) have access to "A-GPS" services, where information about ionospheric conditions and orbital updates are available via a secondary channel. That is, they were the devices least like the ones designed when GPS was new.

    In more detail:

    A) 15 years ago, the amount of digital signal processing necessary to emulate what is a low power couple-buck part in modern cell phone wasn't merely expensive, but flat out unavailable at anything remotely resembling a portable form factor, no matter the price. That's a simple fact of Moore's law. The high roll-off digital filters that modern cell-phones take for granted, which allow very sharp filtering between frequency bands, were not feasible at any reasonable price/form factor tradeoff even 10 years ago, much less 15 to 20 years ago, when the earliest GPS equipment was made. Analog filters, regardless of physical form factor, cannot achieve the same level of filtering. The older devices had no option but analog filters, and those filters are simply not capable of cutting out the level of interference LightSquared transmissions would incur. The filters which were deployed assumed that the neighboring frequencies would have moderate power transmissions from other satellites; if a 1980's era RF engineer had been asked to receive satellite-power signals with terrestrial-power transmissions on a neighboring frequency, said engineer would have claimed it was impossible, and questioned the sanity of putting satellite and terrestrial signals on adjacent frequency bands.

    B) GPS transmits a variety of signals. The most important one is the time-source signal, which allows location and timing. However, there is also secondary data, including the ephemeris and almanac data, which provide corrections to the orbits and updates to current ionospheric conditions. Having the ephemeris and almanac data available make it much simpler to "lock on" to the time-source signal. However, this secondary data is sent over a very low-bandwidth channel, which requires the same level of lock-on as the main time-source signal. In ideal conditions, it can take 12 minutes for this secondary data to be sent; in non-ideal conditions (i.e. with lightsquared's interference) it can be much longer. To improve GPS performance, cell phones typically receive the ephemeris and almanac data directly from the cell tower, rather than waiting for the low-bandwidth signal sent from the GPS constellation. Hence, cell phones can achieve a better GPS signal even in the face of interference, because the signal they need to get a signal (that is, the ephemeris & almanac data) is sent over the reliable cell-phone channel.

    Pure GPS receivers must get the ephemeris data from the GPS satellites, and hence are much more susceptible to interference. 15 to 20 years ago, nobody envisioned a nationwide radio network which could send the ephemeris data to any receiver.

    Simply put, Lightsquared's complaint about the design of currently-deployed GPS equipments sounds is bogus. "You should have been able to predict 20 years of Moore's law, fundamental improvements in the mathematics of digital filter design, the economics of a nationwide radio network with ephemeris data, and further, you should have based your designs around all of those predictions, even though the technology to do so wasn't available".

    Quit crying and buy a terrestrial licensed chunk of spectrum.

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