08.21.2007 09:55 AM
Originally featured on BroadcastEngineering.com
NAB, MSTV file comments with FCC opposing personal/portable devices
The NAB and Association for Maximum Service Television (MSTV) filed comments with the FCC Aug. 16 asserting that letting unlicensed personal/portable devices operate in the DTV band “will cause widespread disruption of digital television service.”
Additionally, spectrum sensing scanners that detect the presence of a TV band user to avoid causing interference “cannot reliably detect occupied digital television channels and are easily broken,” the joint filing said. Authorizing these devices is “extremely risky because if sensing fails, the interference in the television spectrum can go for miles,” the filing said.
The broadcast trade associations filed their comments with the commission on the same day commission staff were scheduled to meet with those interested in the results of the Office of Engineering & Technology’s testing at the FCC Laboratory in Maryland of prototype personal and portable white space devices. The results were used to compile two reports released July 31.
The Aug. 16 filing said there was no basis for allowing personal/portable white space devices to be used in the DTV band and urged the commission to progress with its proposal to authorize fixed devices.
The associations reiterated a theme that has emerged among opponents of personal/portable devices, namely that authorizing their use would “risk the future of America’s television broadcasting system.”
The filing referenced the FCC tests of two prototypes and said the one submitted by Microsoft “failed to detect occupied television channels at the -114dBm level” suggested by the White Space Coalition, high-tech backers of such devices. It also noted that both prototypes failed “to sense effectively at the Further NPRM’s (Notice of Proposed Rulemaking’s) minimum detection level of -116dBm.”
Field measurement reports provided by the associations show that even if such devices could detect at the -116dBm level, “they would still fail to protect television services from harmful interference,” the filing said.
“It is time to focus engineering efforts and resources on successfully completing the DTV transition and moving forward to adopt appropriate protections for the authorization of fixed devices,” the NAB and MSTV filing said.
For more information, visit www.nab.org.