Modeling and Optimization of Channel Allocation for PAL and GAA Users in the CBRS Band

A fundamental challenge for Citizen Broadband Radio Service (CBRS) is how to achieve optimal channel allocation for the Priority Access License (PAL) and General Authorized Access (GAA) users while protecting the incumbent federal users. To address this challenge, we develop a mathematical framework, which encompasses PAL channel allocation, PAL interference protection, GAA channel allocation, and interference protection for Environmental Sensing Capability (ESC) and incumbents per FCC guidelines. Special treatment is given to the so-called spectrum contiguity and geographical contiguity requirements for PAL channel allocation. Through linearization of the nonlinear constraints, we reformulate the original problem into a mixed-integer linear program (MILP) with no relaxation error. We conduct extensive simulation experiments on real-world data for counties along Virginia's east coast and show that our optimal solution can offer guaranteed interference protection to the federal incumbents and PAL holders while maximizing channel utilization for the GAA users. Our simulation study also indicates that although the FCC ruling on channel contiguity and geographical contiguity requirements on PAL holders leads to some performance loss in channel allocation, such a loss is in fact limited.