Pacific DataVision officials address key technical concerns raised about 900 MHz LMR-to-broadband proposal

However, by locating the PDV broadband airwaves between the narrowband spectrum block—as is being contemplated to resolve the AMI interference concern—there should be plenty of separation to address the combiner issue, O’Brien said.

“As it happens, if you solve problem number 1 … by moving down, you significantly assist this problem,” O’Brien said. “By moving the broadband down, you now have a bigger separation between narrowband. You have narrowband in two places instead of just in one place, so you have a better chance to spread [the spectral location for combiners].

“We’re still studying that, and we need to think through all of the implications. But it looks like one solution might fix both problems. This requires us to get into a lot of detailed engineering, and we haven’t done that yet. That process will start.”

Another technical issue raised by commenters is whether a spectral guard band is needed to protect narrowband operations from potential interference from PDV’s broadband deployment.

To date, PDV has not committed to deploying a specific broadband technology, but officials have indicated that LTE would be the likely choice, if a decision had to be made immediately. O’Brien noted that the LTE standard calls for a 3×3 MHz deployment—what PDV is proposing—to have two internal 150 kHz guard bands, with a guard band located on each end of the utilized spectrum blocks.

“Our point is that that’s adequate, based on our understanding,” O’Brien said. “But we’ve launched a process to test it with [a licensee from the petroleum industry].”

Non-technical issues raised by commenters regarding the PDV broadband proposal include a desire by existing licensees to continue operating their LMR system without disruption—O’Brien acknowledged that spectrum realignment is a “nuisance”—and questions about the cost and reliability of PDV’s services.

O’Brien is scheduled to speak today about the 900 MHz broadband proposal during a webinar hosted by EWA that will begin at 2 p.m. Eastern time. Registration for the webinar is free and can be done by clicking here.