Abstract-We discuss optical multi-band orthogonal frequency division multiplexing (OFDM) and show that by using multiple parallel OFDM bands, the required bandwidth of the digital-to-analogue/ analogue-to-digital converters and the required cyclic prefix can significantly be reduced. With the help of four OFDM bands and polarization division multiplexing (PDM) we report continuously detectable transmission of 10 121.9-Gb/s (112.6-Gb/s without OFDM overhead) at 50-GHz channel spacing over 1,000-km standard single mode fiber (SSMF) without any inline dispersion compensation. In this experiment 8 QAM subcarrier modulation is used which confines the spectrum of the 121.9 Gb/s PDM-OFDM signal within a 22.8 GHz optical bandwidth. Moreover, we propose a digital signal processing method to reduce the matching requirements for the wideband transmitter IQ mixer structures required for PDM-OFDM.Index Terms-Chromatic dispersion compensation, fiber-optic transmission systems, long-haul transmission, orthogonal frequency-division multiplexing (OFDM).
IoT requires cloud infrastructures for data analysis (e.g., temperature monitoring, energy consumption measurement, etc.). Traditionally, cloud services have been implemented in large datacentres in the core network. Core cloud offers highcomputational capacity with moderate response time, meeting the requirements of centralized services with low-delay demands. However, collecting information and bringing it into one core cloud infrastructure is not a long-term scalable solution, particularly as the volume of IoT devices and data is forecasted to explode. A scalable and efficient solution, both at the network and cloud level, is to distribute the IoT analytics between the core cloud and the edge of the network (e.g. first analytics on the edge cloud and the big data analytics on the core cloud). For an efficient distribution of IoT analytics and use of network resources, it requires to integrate the control of the transport networks (packet and optical) with the distributed edge and cloud resources in order to deploy dynamic and efficient IoT services. This paper presents and experimentally validates the first IoT-aware multi-layer (packet/optical) transport SDN and edge/cloud orchestration architecture that deploys an IoT-traffic control and congestion avoidance mechanism for dynamic distribution of IoT processing to the edge of the network (i.e., edge computing) based on the actual network resource state.
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