About the SAS

History

This Spectrum Access System (SAS) is the byproduct of the requirements for graduation for Cameron Makin and Joseph Tolley. Both students advised by Dr. Carl Dietrich, development for this SAS began Fall 2019. With the availability of USRPs on CORENET, Dr. Dietrich suggested that a SAS would prove useful for spectrum sharing research.

SAS Procedures

The SAS follows protocols as written by the WinnForum [1].

USRP Registration and Operation Procedure

In order to operate USRPs on the SAS, instances of Nodes in socket_to_sas.py. Once a Node is created, it may then be registered to the SAS. Upon successful registration, the node must make a Spectrum Inquiry request regarding any spectrum they are interested in being granted. If the spectrum inquiry response indicates the channel is available, the Node may then send a Grant request. If the Grant request is approved, the Node will automatically send Heartbeat requests to the SAS and follow any commands given by the SAS. Once the Grant expires, the Node will go idle and may become an environment sensing node, providing the SAS with spectrum information.

Sources

• [1] Spectrum Access System (SAS) - Citizens Broadband Radio Service Device (CBSD) Interface Technical Specification
• [2] Signaling Protocols and Procedures for Citizens Broadband Radio Service (CBRS)
• [3] FCC Part 96 for CBSDs