DPAs and SAS Error : International border rule violation

For the last two nights, we have had DPAs in our area and when this happens the AP Has not tried to get another grant it just goes down and we get a Syslog message that states SAS Error : International border rule violation.

Has anyone experienced this on a 450M running 21.0

Are the AP’s having this issue shooting at or around an international border? I’ve never had this happen, but I’d recommend a couple things.

Update just the AP’s to the newest R21.1.0.1 beta. There’s CBRS improvements and fixes in pretty much every release these days.

You may want to double check your CPI data for those AP’s and tighten them up a bit. Like using 1m accuracy. You may also want to temporarily artificially increase your downtilt and/or reduce your AGL to make it appear as though your shooting lower then you actually are. If that fixes the issue, then go up to the tower and make the physical changes.

Thanks, we are pretty close to an international border. Modeling in the federated portal shows that our PPA ends almost at the border but our coex curves are miles from it. we are already shooting 5 deg downtilt as we don’t need to cover the water near the border

This is a new issue this AP has been running since early 2020 so I’ll try the upgrade

I had a brief exchange with Jesse-Nikola yesterday, but wanted to provide an update here after some additional discussions between Cambium and Federated Wireless. When the DPA on Jesse’s sector was activated, Cambium’s alternate channel selection algorithm did kick in automatically. We queried the SAS via a Spectrum Inquiry exchange and the SAS suggested channels just below 3700. So the AP did make a grant request for 3690 - 3700, but that grant request was immediately rejected by the SAS as a border violation. The upper 50MHz is more restrictive on available EIRP near the Canadian border. Although Federated Wireless has not committed to a fix, they are open to it and will be discussing more internally over the next few days.


I wanted to provide an quick status update here on this topic. The discussions with Federated Wireless on them modifying their algorithm so they no longer offer this channel in the Spectrum Inquiry Response are still in progress. In parallel, Cambium has raised an enhancement ticket on our own code to attempt a different channel in this situation, rather than simply dropping back to the previous suspended channels. I don’t have a target date on either improvement at this time.

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