In an expected outcome given the opposition, but moving unexpectedly fast, the FCC has switched off LightSquared – the nationwide LTE carrier developing an open-access, wholesale wireless broadband network integrating satellite and terrestrial technology. In 2004, the FCC allocated L-band spectrum (1525-1559 MHz) to LightSquared adjacent GPS L1 band. This caused some concerns within the GPS industry, military, airlines, transportation, science community and ultimately consumers.
The technology available from the GPS industry was not designed to effectively filter adjacent band interference, but it wasn’t a problem as there were no competing uses in that band. There were proposed uses, but these were long on plans and short on execution. The interesting part, upon reflection, is the GPS industry had known that the adjacent frequencies might be used for these competing purposes almost a decade ago and could have responded by redesign and retooling receivers. LightSquared made significant efforts to address any potential interference problems with the industry.
After some initial interference testing, LightSquared moved further away from GPS L1 (1575.42 MHz) some 23 MHz from the lower edge of L1. As Michael Marcus of Marcus Spectrum Solutions observes – that is almost 4 US TV channels or almost 3 European TV channels.
For a prosumer level explanation of what was going on – I recommend Dr. Marcus and his take on the issue: GPS, Lightsquared and Boaters. He has more keen insights on the controversy here, here and here. Highly recommended.