Research On Protection Mechanisms For Fiber-Wireless Access Network

The emergence of new broadband services such as 8K/4K video,smart homes,and cloud computing has led to a dramatic increase in global traffic and the desire for better network service quality from users.The explosive growth of traffic and the higher demands on networks from users have accelerated the research process of next-generation optical network architectures.The traditional three-layer network architecture can no longer meet the requirements of future optical networks.Metro-access integrated optical networks simplify the network structure through node consolidation,thereby decreasing operating costs,reducing signal processing delays,and breaking the constraints of electronic bottlenecks.As a result,researchers currently widely believe that metro-access integration is an inevitable development trend.Moreover,the integration of fiber access and wireless access further facilitates the seamless integration of wired and wireless services to meet the requirements of high bandwidth and low latency of 5G services.However,in such a highly integrated optical network,the occurrence of fiber failure will result in the loss of more traffic capacity than in the past,which will cause greater losses for users.Therefore,it is important to study efficient protection mechanisms to improve network reliability.In previous studies on protection mechanisms for optical networks,three main types of approaches based on optical path protection,wireless protection,and hybrid protection are reported,but the existing schemes based on these three approaches have shortcomings.They are difficult to apply to the protection of fiber faults in high-capacity communication scenarios with high reliability and low cost.Therefore,to address the deficiencies of existing studies,an efficient protection mechanism for resisting fiber faults is proposed,as follows:(1)In this thesis,a protection mechanism based on the protection approach of integrating a dual-fiber ring architecture and microwave link is proposed.The dual-fiber ring architecture is used for the protection of the feeder fiber.Microwave links are used for the protection of the distribution fiber.This scheme can achieve fiber-wireless integrated access while also improving network reliability in high-capacity communication scenarios at a lower useraverage cost.(2)In this thesis,an optical switch module(OSM)is designed and developed,which combines a dual-fiber ring architecture to support the protection mechanisms against four types of feeder fiber faults and the cancellation of Rayleigh backscatter(RB)noise to improve the optical transmission performance of the uplink.This scheme can not only be applied in actual engineering practice but can also meet the requirements of future optical networks regarding low latency due to its upgradeability.(3)In this thesis,the colorless scheme of optical network units(ONUs)based on a reflective semiconductor optical amplifier(RSOA)is used to reuse the wavelengths of downstream optical signals,as it has the advantages of low user-average cost and high spectral utilization.Moreover,the optical transmission performance of each operating scenario of the network is improved by optimizing the set parameters of the RSOA to suppress the RB noise and improve the signal-to-noise ratio of the modulated upstream optical signal.(4)In this thesis,not only are the network scale,network reliability,network cost,and optical transmission performance analyzed by simulation,but the quality of service(QoS)of the network is also evaluated.The OSM is developed and experimentally tested.The relevant performance indicators obtained from the experiment contribute to the simulation of optical transmission performance to enhance the reliability of the results and give the scheme high feasibility.In this thesis,a protection mechanism based on the approach of integrating a dual-fiber ring architecture and microwave link is proposed.It not only improves the network reliability while considering cost-effectiveness but also has the advantages of large network scale and upgradability.The protection mechanisms can meet the reliability requirements for future fiberwireless integrated access networks.