The Federal Communications Commission, on Thursday, came out with its verdict in the long-standing spectrum dispute between T-Mobile and Sirius XM Holdings, owners of the Sirius Satellite Radio service. As was being speculated in some quarters of the media, the federal regulator announced that going by the insufficient evidence presented by Sirius to support its case, it has no objection if the carrier went ahead with its proposed spectrum swap with the country's largest wireless carrier, Verizon Wireless. As a little background into the whole case, earlier this year, Verizon and T-Mobile signed an agreement to trade some AWS and PCS spectrum licenses with one another, but subscription-based satellite radio service provider Sirus XM tried to get the transaction blocked. According to Sirius, T-Mobile's AWS cell sites were causing interference for its subscribers in some urban markets.
With Thursday's verdict, the FCC made it clear that it couldn't stand in the way of the swap of regulated spectrum between two entities who are doing everything in keeping with regulations as laid down by the FCC. However, the commission did advise Sirius that if it still feels T-Mobile's use of the airwaves is creating problems, it could get that complaint addressed through a separate filing. As per a report from the Wall Street Journal, speaking in the aftermath of the FCC reversal, a Sirius XM spokesman, Mr. Patrick Reilly, claimed that the company is "working constructively" on the problem but will be forced to pursue "other avenues" if T-Mobile continues to stonewall its demands. For its part, the carrier maintains that it is doing everything according to the rule book, and the so-called interferences, if any, are a result of Sirius's faulty equipment.
According to people in the know, the problem being experienced by Sirus' subscribers, is called 'intermodulation distortion' (IMD), which is described on Wikipedia as the "amplitude modulation of signals containing two or more different frequencies, caused by nonlinearities in a system". In simpler terms, two different frequencies being used by T-Mobile for its signals, are apparently combining to create an additional signal at a different frequency that is not harmonically related to either of the original signals. Now, unfortunately for Sirius, one of those frequencies that is being affected because of the extrapolated convergence of the two frequencies in use by T-Mo, is exactly what Sirius is using for its transmissions, resulting in the distortion.