NTIA Comments on Technical Issues Raised in Further Notice of Proposed Rulemaking on Global Mobile Personal Communications by Satellite
The National Telecommunications and Information Administration (NTIA) supports the Federal Communications Commission (Commission) in its efforts to implement the international Memorandum of Understanding regarding Global Mobile Personal Communications by Satellite (GMPCS-MOU), which will support the deployment of GMPCS service in the United States and around the world. These GMPCS systems will provide additional choices for the delivery of seamless voice and data services for consumers in all parts of the world. NTIA would like to continue the arrangement established in the GMPCS Report and Order that would greatly facilitate the global roaming of mobile satellite service (MSS) mobile earth terminals (METs), while protecting critical Government operations. NTIA offers the following comments that are limited to specific technical issues raised in the GMPCS Further Notice of Proposed Rulemaking. NTIA agrees with the Commission that it generally serves the public interest to foster international uniformity in technical requirements for MSS METs. The equivalent isotropically radiated power (EIRP) limit of -80 dBW/MHz proposed by NTIA for the carrier-off state is consistent with the international standard. The NTIA proposal for carrier-off emission measurements would use the same bandwidth and detector function as used for the carrier-on emission measurements, thereby simplifying the compliance measurements. From the standpoint of interference potential to Global Navigation Satellite System (GNSS) receivers, the emission limits proposed by NTIA and the Commission achieve the same goal. However, NTIA believes that, to simplify the compliance measurements, the Commission should adopt an EIRP density of-80 dBW/MHz for the carrier-off state emissions of MSS METs.
NTIA also recommends that the Commission specify a measurement time interval of 2 millisecond (msec) for the MSS MET out-of-band emission measurements in the 1559-1605 MHz band. A measurement interval of 2 msec would ensure that the emissions are measured when the MET is transmitting, while at the same time accurately quantify the interference potential to both Global Positioning System (GPS) and Wide Area Augmentation System (WAAS) receivers.
Finally, NTIA believes that failure to specify the nature of the detector will negatively impact compliance with the MSS MET emission limits. NTIA accordingly recommends that the Commission specify a root mean square (RMS) detector for making these measurements. The RMS emission level should be measured using an averaging time of 2 msec or less. Further, the specification of an RMS detector should be applicable to the wideband and narrowband emission limits in the 1559-1605 MHz band for both the carrier-on and carrier-off states of the MSS METs.