電気通信システムと管理

Experimental Characterization of Sigma Delta Radio over Fiber System for 5G CRAN

Abstract

Muhammad Usman Hadi

Radio over Fiber (RoF) is an apting technology for the next generation wireless networks including 5G Cloud Radio Access Network (C- RAN). Digital Radio over Fiber (D-RoF) networks are immune to nonlinearities that arise in Analog Radio over Fiber (A-RoF). However, with increase in carrier frequencies and baud rate, the D-RoF cost becomes crucial. There exists a possibility to use Sigma Delta Radio over Fiber (S-DRoF) that combines the advantages of A- RoF and D-RoF by means of Sigma Delta Modulator (SDM) at the transmitter side subsequently replacing the employment of expensive and high-speed digital to analog converters. In this paper, we demonstrate the usage of 2nd order SDM for LTE 20 MHz signal having 256 QAM modulation on a central carrier frequency of 2.475 GHz for the implementation of S-DRoF for 10 Km of Standard Single Mode Fiber with baud rate from 25 to 100 Mbaud. Withal, a comprehensive analysis of the design of SDM is explained followed by the experimental setup. The performance is reported in terms of error vector magnitude, and adjacent channel leakage ratio. The results show that the proposed architecture performance is within the LTE specifications, proving this is a cost and power effective solution for next generation wireless networks.