Committee: 

Dr. Chang, Advisor      

Dr. Ma, Chair

Dr. Barry

Abstract: The objective of the proposed research is to investigate and mitigate the nonlinear signal impairments in a multi-service heterogeneous mobile fronthaul network. In advanced mobile data communications, heterogeneous mobile fronthaul networks were proposed to aggregate multiple wireless services from various radio access technologies, and convey them together by exploiting radio-over-fiber technique, which present not only the opportunity of capacity enhancement, spectral efficiency improvement, as well as the flexibility and scalability for the next generation fronthaul networks, but also the challenges of nonlinear signal impairments due to the imperfect channel response in the fronthaul network segment. In our investigation, we will start from the nonlinear cross-modulation effects of single-carrier signals, and then extend to nonlinear subcarrier intermodulations of multicarrier signals, both with focus on the  inter-band interferences in the scenarios of multiband/multi-service operations. Theoretical analysis and experimental validations will be carried out, and nonlinearity mitigation techniques will also be developed, including predistortion to compensate the nonlinear channel response, and digital fronthaul architecture based on delta-sigma modulation to enhance the signal robustness against nonlinear distortions.