Use of the wireless spectrum is increasing. In order to meet the throughput requirements, Dynamic Spectrum Access is a popular technique to maximize spectrum usage. This can be applied to the Citizen Broadband Radio Service (3550-3700MHz), a band recently opened by the Federal Communications Commission for opportunistic access. This radio band can be accessed as long as no higher priority users are interfered with. The top priority users are called incumbents, which are commonly naval radar. Naval radars transmit a focused beam that can be modelled as a periodic function. Lower tier users are prohibited from transmitting when their transmissions coincide and interfere with the radar beam. The second and third tier users are called Priority Access Licensees and General Authorized Access, respectively. Lower tier users must account for the transmission outage due to the presence of the radar in their scheduling algorithms. In addition, the scheduling algorithms should take Quality of Service constraints, more specifically delay constraints into account. The contribution of this thesis is the design of a scheduling algorithm for CBRS opportunistic access in the presence of radar that provides Quality of Service for users, consider different traffic needs.

This was implemented using the ns-3 discrete-event network simulator to simulate an environment with a radar and randomly placed radios using LTE-U to opportunistically transmit data. The proposed algorithm was compared against the Proportional Fair algorithm and a Proportional Fair algorithm with delay awareness. Performance was measured with and without fading models present. The proposed algorithm better balanced Quality of Service requirements and minimized the effect of transmission outage due to presence of the radar.

Library of Congress Subject Headings

Cognitive radio networks; Citizens band radio; Radio resource management (Wireless communications)

Publication Date


Document Type


Student Type


Degree Name

Computer Engineering (MS)

Department, Program, or Center

Computer Engineering (KGCOE)


Andres Kwasinski

Advisor/Committee Member

Andreas Savakis

Advisor/Committee Member

Alexander Loui


RIT – Main Campus

Plan Codes