Virginia Tech® home

Enabling CBRS Experimentation through an OpenSAS and SDR-based CBSD

The increased demand for spectrum has motivated the Federal Communications Commission (FCC) to open band 48, also known as the Citizen Broadband Radio Service (CBRS) band, spanning 3.55 to 3.7 GHz, for shared wireless broadband use. 

Access and operations in the CBRS band is managed by a dynamic Spectrum Access System (SAS) that enables seamless spectrum sharing between incumbent and secondary users. 

In this paper, CCI researchers demonstrate an enhanced version of an open source SAS [1], OpenSAS, with added functionality to showcase interaction between General Authorized Access (GAA) and Priority Access License (PAL) user tiers. 

We further showcase the use of the Google SAS Test Environment [2] with OpenSAS and a Software-defined Radio (SDR)-based CBRS Base Station Device (CBSD) developed by our team. 

Spectrum sharing is achieved by using a client on the CBSD that is in continuous communication with the SAS to conform to its spectrum usage and transmission power rules at a given location. 

Researchers’ demo stepped through the entire SAS-CBSD cycle which includes registration, spectrum inquiry, grant request, heartbeat request, grant relinquishment, and de-registration.