Radio over fiber link design for the fronthaul of cellular communication systems

To address growing bandwidth requirement, the design of fronthaul link of cellular communication systems is critical. Radio over Fiber (RoF) is a promising solution for the fronthaul. In this work, RoF link is simulated and designed for the fronthaul of Centralized Radio Access Network (CRAN). The RoF link is simulated in OptiSystem tool and its link gain parameter S21 is calculated for frequencies upto GHz. The RoF link is then designed and fabricated. Link gain obtained in simulations is verified by practically measuring the link at various optical and RF input powers. Commonly used modulation formats in 4G-LTE such as QPSK, 16-QAM, 32-QAM and 64-QAM are simulated over the link. Performance comparison of modulation schemes is done in terms of BER vs SNR graphs, Error Vector Magnitude, Reach vs Capacity and receiver sensitivity. Results show that QPSK travels for a longer distance but gives low datarate whereas 64-QAM has a shorter reach but gives higher datarates.