Title:  Nonlinear Impairments and Mitigation Technologies for the Next Generation Fiber-wireless Mobile Fronthaul Networks

Committee:

Dr. Gee-Kung Chang, ECE, Chair , Advisor

Dr. Xiaoli Ma, ECE

Dr. John Barry, ECE

Dr. Geoffrey Li, ECE

Dr. Yao Xie, ISyE

Abstract:

The proliferation of Internet-connected mobile devices and video-intensive services are driving the growth of mobile data traffic in an explosive way. The last mile of access networks, mobile fronthaul (MFH) networks, have become the data rate bottleneck of user experience. The objective of this research are two-fold. For analog MFH, nonlinear interferences among multiple mobile signals in a multi-RAT multi-service radio-over-fiber (RoF)-based MFH system are investigated for the first time. The nonlinear impairments of both single-carrier and multi-carrier signals are investigated, and it is experimentally demonstrated that inter-channel interferences play a more important role in the MFH performance degradation than distortions of each individual signal. A linearization technique based on digital predistortion is also demonstrated. For digital MFH, we experimentally demonstrate a novel digitization interface based on delta-sigma modulation to replace the state-of-the-art CPRI. Compared with CPRI, it provides improved spectral efficiency and enhanced fronthaul capacity, and can accommodate both 4G-LTE and 5G mobile services.