MIMO–OFDM based optical millimeter wave generation for radio over fiber wireless communication systems
摘要
In this paper, 4 × 4 Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) based optical (mm) wave generation for Radio Over Fiber (RoF) wireless communication systems has been proposed. As the bit error rates (BER) of external modulation RoF is near to zero compared to direct modulation (5 × e−21 BER), we have opted with Machzehnder modulator (MZM) and direct and coherent detection OFDM has been proposed for mm wave generation. The efficiency of coherent detection OFDM on the RoF has been analyzed at high data rate of 20 Gbps for a 100-Km optical length. Based on comparison of 4-QAM (Quataure Amplitude Multiplexing), 16-QAM, and 64-QAM techniques, it has been proved that 64-QAM has a very low BER and a better constellation than other modulation formats. The novelty of this proposal has been analyzed in terms of received power threshold, quality factor and BER for various fiber lengths from 10 to 100 Km at the data rate of 10 and 20 Gbps. This mm wave generation has been compared with similar generation to validate the improvement in terms of data rate with reduced BER for long distance optical applications.