‘Engineering Trade-Offs’ Make ATSC 3.0 Smartphone Mandate ‘Inappropriate,’ Says Skyworks
The “engineering trade-offs” of building ATSC 3.0 reception into smartphones would make a tuner mandate “inappropriate" for those devices, and the FCC should “refrain from considering such a requirement sought by the broadcasters,” said Skyworks Solutions, a supplier of front-end modules and other components for smartphones, in a filing posted Friday in commission docket 16-142.
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Skyworks joined six others, including Ericsson, Ethertronics, Motorola Mobility, Nokia, Qualcomm and T-Mobile, all weighing in at the FCC since mid-September to fight what they described as broadcasters’ calls for 3.0 tuner mandates in smartphones (see 1709200016). Only the Advanced TV Broadcasting Alliance of low-power TV interests and Free Access & Broadcast Telemedia expressly called for 3.0 mandates in smartphones when 3.0 broadcasts reach at least 25 percent of the population (see 1709130050). NAB said it "consistently made plain" throughout the 16-142 proceeding that it never advocated a 3.0 tuner mandate for fixed or mobile devices (see 1709250053). The FCC's February NPRM was silent on the issue of 3.0 mandates in smartphones, but "tentatively" concluded a tuner requirement won't be needed for now in fixed devices (see 1702270059).
With its experience as an analog semiconductor supplier for mobile devices, Skyworks has a “deep understanding of smartphone design impacts,” and has “followed the recent debate in the ATSC 3.0 docket,” said the filing. “With this letter, we add to the growing record in this proceeding which indicates that adding such capability to a smartphone in its current form would be a non-trivial task and would have many detrimental effects on performance,” it said.
To build a receiver front-end into a smartphone that would accommodate both 3.0 and 600 MHz LTE functionality “would require design changes to add diplexing architecture to the RF circuitry,” said Skyworks. The additional hardware would be needed “to separate the signals from these two disparate bands for routing to the correct receiver for demodulation,” it said. “As with adding any filtering technology to a device, there is some degree of associated insertion loss.” Skyworks estimates that could reduce LTE “cell edge coverage radius” by 20 percent or more, “thus requiring the addition of more cell sites or increased power in the smartphone to compensate,” it said.
Receiver “degradation of 3.0 signals may also require adding a low-noise amplifier to the smartphone “to compensate for such loss,” said Skyworks. “Thus, there would be detrimental consequences to attempting concurrent operability of LTE and ATSC 3.0 in the band.”
Skyworks also joined other opponents in arguing against 3.0 mandates in smartphones because of the form-factor compromises they say would result. The company concluded that adding a 3.0 tuner capability “would have adverse impacts to the normal operation of a smartphone” using 600 MHz LTE technology, “and such action is not recommended,” it said. “Current smartphone form factors, which are popular with the public, cannot simply be modified to add such capability, and the significant impact on user experience for both general cellular services as well as e911 on LTE cannot be recovered through other architecture/design/technology changes in the radio front-end solution.”