Generation of 40 GHz/80 GHz OFDM based MMW source and the OFDM-FSO transport system based on special fine tracking technology

摘要

We have experimentally proposed and demonstrated a hybrid OFDM based optical MMW source and OFDM-FSO transport system employing special fine tracking technology. In this paper, 10 Gbps/40 GHz and 10 Gbps/80 GHz MMW source are successfully transmitted over 50-km and 25-km SMF as well as 20-m wireless link by employing variable length single mode fiber. 10 Gbps base band signal is successfully transmitted over 500-m FSO link with the assistance of special tracking and pointing technology. A position sensitive detector (PSD) is used in a fine tracking system, due to its much greater detection ability as compared to the conventional charge coupled device (CCD). Greater position resolution and high sensibility of PSD helps to communicate our signal over 500-m optical link. The limitation of dispersion and ISI effect in our wireless network are combat by employing appropriate length of cyclic prefix (CP) in our OFDM system. Here, we study the BER performance of the system by varying the length of CP. The proper length of CP boosts the system capacity and enhances the overall system performance. Low BER, good EVM (similar to 12%), clear constellation diagrams proved the reliability and feasibility of our system as a prominent solution for multiservice wireless network.