Evaluation of Nonlinear Effects in a RoF SpatialMux MIMO-LTE Fronthaul System

摘要

This paper analyzes the optimum transmission conditions of a radio-over-fiber (RoF) fronthaul system in multiple-input multiple-output (MIMO) schemes. By varying different transmission parameters, such as the laser bias current or the input signal power, it is possible to minimize the nonlinear effects produced by the RoF system. The experimental setup consists of an intensity modulation/direct detection (IM/DD) scheme with 10 km-length. The carrier frequency is set to 2.65 GHz, within the band 7 of the LTE standard. LTE MIMO signals with several bandwidths and modulations are applied in order to carry out the experiments. Results show that with a properly bias current and input signal power it is possible to minimize the distortions of the system, improving Adjacent Channel Power Ratio (ACPR) and Error Vector Magnitude (EVM) values.