Why are only some of my grants in an area getting DPA suspensions?
CBSD operators sometimes wonder why only a portion of grants in a given area are suspended due to the activation of a DPA. This is especially the case if most or all of the grants in an area share very similar characteristics, such as frequency range, but only some are suspended. This issue most commonly occurs when the CBSDs in an area have one or more new grants that have not been held through CPAS yet.
Any CBSD registered within a certain proximity of a DPA is considered within its DPA Neighborhood. Per WInnForum requirements, all new grants that overlap with the DPA’s protected frequencies (generally 3550-3650 MHz) must be placed on that DPA’s movelist. A movelist is a list of grants the SAS has determined must be suspended to protect higher priority users from interference when the SAS detects incumbent activity with overlapping frequency range in that DPA. When the SAS does its interference calculations at CPAS, grant movelists are also recalculated. A grant that has gone through CPAS is likely to be removed from some or all of the movelists it was initially placed on. Grants that have not been held through CPAS are therefore more likely to be suspended due to DPA activation than grants that have. As a result, it is recommended that a CBSD hold its grants through CPAS even if they are getting suspended on the first day they were requested. This is especially the case if similar grants in the area are not being suspended. The age of a suspended grant checked by looking at the information listed in the CBSD’s History tab in the SAS Portal. Any grant requested in the last 14 days will be listed.
For more information please read the following articles:
Please note that this is not the only reason that only some grants might be on DPA movelists. Registration parameters such as azimuth, beamwidth, CBSD location, and the geographical features at that location can all play a role. Alternatively, aggregate interference in an area can rise to the level that borderline grants might be placed back on DPA movelists. If grants continue to be on DPA movelists after CPAS, it is likely due to some or all of these factors.
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