The modern advancements have been made to form Next-Generation Ethernet Passive Optical Networks (NG-EPONs); it has been developed for handling the heavily bandwidth-demanding applications like HD video streaming, virtual/3D gaming, cloud computing-based applications, and virtual corporate working ecosystems. NG-EPON has been designed to provide ultra-high bandwidth with reliability and efficient resource management as compared to existing traditional Ethernet Passive Optical Network (EPON) systems. NG-EPON is basically a hybrid system that has been formed by collectively integrating time division multiplexing (TDM) and wavelength division multiplexing (WDM) features for effective data communication of future access networks. A hybrid system has been designed for the attainment of enhanced performance and cost efficacy. WDM-EPON system provides dedicated wavelength channels to the subscriber ONUs for high bandwidth, but with challenges of very high operational cost and channel underutilization. NG-EPON, as a hybrid system, mitigates the limitations by optimally allocating the wavelength channels and maintaining high performance in terms of bandwidth provision to bandwidth-hungry applications. The role of dynamic wavelength and bandwidth allocation (DWBA) algorithms for efficient bandwidth utilization in NG-EPON is our main point of concern in this study. To the best of our knowledge, the survey presented here is the first cohesive and up-to-date survey on the evolution towards NG-EPON. Novel contributions include the combination of DBA and DWBA algorithms in one framework and assessment of these combined algorithms within TDM-, WDM-, Hybrid-, and AI/ML-based categories. Additionally, this paper incorporates the discussion of machine learning, reinforcement learning, and federated learning based DBA approaches—topics rarely covered in prior works. Our study discusses and comparatively analyzes the different bandwidth utilization DWBA algorithms for NG-EPON. The study also examines time and wavelength division multiplexing strategies, addresses the challenges for DWBA, and provides us with the improved algorithms that have been designed and implemented in recent years. Additionally, the role of DWBA algorithms in improving bandwidth efficacy is analyzed, with a focus on QoS-aware algorithms. With NG-EPONs capable of delivering 25 Gbps per channel, these technologies play a crucial role in shaping future high-capacity optical access networks.
Rafiq et al. (Tue,) studied this question.