Inquiry Regarding CBRS Operations in Coastal Areas of Alaska

[heisenberg600]

Hey !

I have attempted to operate a CBSD near the coastal areas of Alaska, but I am encountering an issue where no available channels are detected, and the channel qualities of all frequency ranges are reported as 0 at this location, as shown on the SAS portal UI.

As per the information available in this link, it states:
"Due to their proximity to the ocean, many non-contiguous US locations in Hawaii, Alaska, and Guam except American Samoa are included in Dynamic Protection Area (DPA) neighborhoods. There is no Environmental Sensing Capability (ESC) network to protect these DPAs, so spectrum availability from 3550 MHz to 3650 MHz is restricted. American Samoa has access to the full CBRS spectrum."

Could you please clarify the specific restrictions when operating in Alaska with respect to SAS? The link mentions that there is a restriction while operating in the 3550-3650 MHz range, but later also notes that the 3550-3700 MHz range is available. I would appreciate clarification on this.

Additionally, could you advise on the best policies and practices to follow when deploying CBRS in Alaska, especially in coastal areas?

Looking forward to your insights.

[James_S · Accepted solution]

@heisenberg600 

There is no ESC network in Alaska, so the SAS doesn't know when there is naval activity in the area. Therefore, it must treat all coastal DPAs in those locations as if they are constantly activated across all DPA channels (3550-3650 MHz). If your device is located far enough away from the DPAs, or is low enough power that it would be placed on no movelists, then the full 150 MHz would be available to you. If not, only the non-DPA related channels (3650-3700 MHz) would be available. 

If your devices are being registered close to the coast, it is likely that only 3650-3700 MHz would be effectively available to you, because the remaining channels would be suspended all the time. You might want to use DPA neighborhood overlays in the SAS Portal to give you a rough idea of where the "danger zone" is for various kinds of devices. From checking on my end, it seems like the only devices that could operate on all channels near the coast are Cat A devices with height above average terrain (HAAT) of < 6 meters 

[heisenberg600]

Thanks for your prompt response.

I have one follow-up question based on your answer. From your explanation, it seems that the upper 50 MHz of the spectrum would always be available. However, I am observing that even this portion is being reported as unavailable near the coast. Could you please help clarify this behavior and how we should interpret this?

[James_S]

@heisenberg600 

That's an excellent follow-up question.

Let me clarify the nuance here. The rule is that only the upper 50 MHz has the potential to be available, but it is not guaranteed to be available everywhere. Other factors could restrict availability in certain locations, such as being extremely close to an FCC quiet zone.

In order to investigate the specific channel availability you're seeing, I'll need a bit more information:

• The physical location.
• What tool is reporting the channels as unavailable.

Once I have those details, I can look into it further.