Research of DBA schemes and QoS in PON system

With the further promotion of smart city, optical access for replacing copper access and integration of three networks, PON is widely considered as the best option for next-generation high-speed access network owing to its advantages such as high bandwidth, low cost and good compatibility. However, its point-to-multipoint topological structure is born with the problem of bandwidth allocation scheduling and there are serious security risks in its downlink broadcasting transmit mode, which impose restrictions on the widespread use of the technology. After making a detailed analysis and comparison of the existing bandwidth allocation algorithm, the deterioration of light load, low utilization rate of bandwidth, poor fairness and inability to guarantee QoS are pointed out and the original dual-clocking DBA algorithm is put forward. Meanwhile, OLT/ONU bidirectional authentication during registration is proposed and Diffie-Hellman key exchange protocol is introduced. The information that can perform key exchange is embedded into authentication information and passing another initial key is no longer needed for the following data encryptions, which strictly ensure system security in the authentication step. The experimental results show that this scheme has a great advantage in reducing average delay, queue delay and throughput of system as well as improving system security.