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A Study of Timing Constraints and SAS Overload in the CBRS Band using SAS-CBSD Protocol



Anirudha Sahoo, Naceur El Ouni, Vineet Shenoy


In the Citizens Broadband Radio Service (CBRS) band, the Federal Communications Commission (FCC) has set stringent timing constraints for the lower tier users to vacate the channel when an incumbent shipborne radar appears. The standards body formulating various specifications for the CBRS operation, has taken these timing constaints into consideration in the Spectrum Access System (SAS) -- CBRS Device (CBSD) protocol. A transmitting CBSD constantly heartbeats with its SAS. When required, the SAS sends commands to vacate a channel through these heartbeat messages. In this paper, we study the impact of heartbeat interval on the CBRS system in terms of meeting the FCC timing constraints. We also study how the heartbeat interval can overload a SAS and can be used to determine the number of CBSDs a SAS can serve without causing unnecessary suspension of transmission of CBSDs. We show the tradeoff between short heartbeat interval to meet the timing constraint early and the number of CBSDs that can be served by a SAS without causing unnecessary suspension of CBSD transmission.
Conference Dates
December 9-13, 2019
Conference Location
Wikola, HI
Conference Title
2019 IEEE Global Communications Conference (GLOBECOM)


CBRS, Spectrum Access System (SAS), CBRS Device (CBSD), 3.5 GHz
Created December 9, 2019, Updated December 2, 2019