Extended TX expiry time and heartbeat interval for CBRS/SAS users

[Eric_Ozrelic]

Good news for CBRS/SAS users! Google and Federated have finally enabled the extended TX expiry time and the heartbeat interval which should significantly increase system stability when there are network issues, cloud issues, SAS is unavailable, etc. Cambium issued an email yesterday with guidance on how best to use this new feature, along with a guide from Federated on how to enable this new feature. I’ve gone ahead and made this Cambium email and the Federated guide public via the provided Google Drive link. NOTE! I do not have instructions from Google, but I do believe you have to opt-in to that program as well. If you find instructions, please let me know and I’ll put them in this public folder.

https://drive.google.com/drive/folders/1rxM_iBfDGohylweu_71-pCNSuJEpRwox?usp=drive_link

Mike Glish Mike.Glish@cambiumnetworks.com

CBRS Services

New Federated Wireless Features

Federated Wireless has introduced a new feature that extends the Tx expiry time and the heartbeat interval. Customers interested in taking advantage of this feature need to opt-in. Details of the feature and how to opt-in are included in the message from Federated Wireless below.

When testing the feature with Federated Wireless, Cambium has made the following observations:

Devices should be at release 22.1.1 or above. This is the release used for testing; older releases should work but have not been explicitly tested. As a general rule, it is always beneficial to be at one of the newest releases especially when operating in CBRS band.

After opting in, the device receives the new Tx expiry time from the SAS and it applies it immediately. This is the most beneficial aspect of the new feature, as a device does not need to immediately stop operation if connectivity with the SAS is lost.

When the device receives the extended heartbeat interval, it does not immediately apply it. A reboot of the AP is necessary for the entire sector (AP and SMs) to start using the new value. There is no immediate benefit to the device in going to an extended heartbeat interval; the advantage is an overall lower load to the SAS, as fewer messages are sent from the devices.

Note that when moving to a new grant (for example, when changing channels), the device will receive the older (smaller) heartbeat interval from the SAS and does not switch after the SAS sends the new value. Again, a reboot would be needed to take the new larger value. But operationally there is no significant difference from the device point of view when it operates with the smaller or larger heartbeat

If you have any questions about this topic or any other CBRS technical topic, please open a ticket with Cambium Support at https://support.cambiumnetworks.com. Regards,

Mike Glish
CBRS Program Manager