On Communication Reliability of General Authorized Access Device on Citizens Broadband Radio Service
In 2015, the Federal Communications Commission approved the usage of the 3.55 GHz - 3.70 GHz (i.e., band~48) spectrum opportunistically for commercial purposes. Since then, the 150 MHz bandwidth, also known as the Citizens Broadband Radio Service (CBRS), has attracted the attention of the leading telecommunication industries and the research communities. The CBRS spectrum has a hierarchical access architecture where the original owners of the CBRS spectrum, i.e., the incumbents, have the highest and uninterrupted transmission authority. As the incumbent transmission is sparse, the unused spectrum is opportunistically shared between the Primary Access License (PAL) users and the General Authorized Access (GAA) users. Both the user groups get approval to communicate on the CBRS spectrum from the Spectrum Access System (SAS), which acts as a cloud-based centralized administrator of the CBRS and is responsible for ensuring non-compromised incumbent operation on the CBRS. Note that the GAA users do not purchase the spectrum access through auction as PAL does and has the slightest preference to communicate on the CBRS. In this paper, we study the communication reliability of a GAA CBRS Device (GAA CBSD) when the approval from the SAS administrator to communicate on the CBRS spectrum is considered. Our experimental observations show that the deployed GAA CBSD remains uncommunicative for a sizable amount of the observed time duration as the SAS administrator does not allow the GAA CBSD to communicate on the CBRS to protect the incumbent/PAL transmissions.