Dedicated and broadcasting downstream transmission with energy-efficient and latency-aware ONU interconnection in WDM-PON for smart cities

Abstract

Abstract Currently, Internet of Things (IoT) and use of Information & Communication Technology (ICT) have gained a lot of attraction for developing the smart cities. Wavelength division multiplexed passive optical networks (WDM-PON) are popularly used for supporting the high data rate IoT and ICT services. With the exponential growth of users and traffic demand in access networks, large energy consumption, OPEX, service reliability has become the most challenging bottleneck for smart cities. This paper proposes a flexible, wavelength division multiplexed passive optical network (WDM-PON) architecture which provides a dedicated point to point (P2P), broadcasting downstream transmission and latency-aware direct optical network units (ONUs) interconnection. Broadcasting downstream transmission is achieved by diverting a particular wavelength from the main path towards (N + 1) × (N + 1) star coupler (SC). Direct ONU interconnection is accomplished by separating the inter-ONU signal from the upstream path by using 50 GHz interleaver at the remote node (RN) and redirecting it towards ONUs. Direct ONU intercommunication avoids the complex re-routing, re-scheduling and re-modulation of the inter-ONU signal at optical line terminal (OLT) and thus increases the reliability and energy efficiency of the network. Broadcasting enables the best resource utilization, and direct ONU interconnection reduces the significant transmission latency among different communicating users. Proposed architecture reduces the operational cost and energy consumption of the network by reducing the processing by some components. By reducing the extra burden of the inter-ONU signal on downstream bandwidth, proposed architecture also provides the efficient bandwidth utilization.