With the continuous improvement of social information and the emergence of large number of terminals, the traditional time division multiplexed passive optical network cannot meet the higher bandwidth requirements of users. The wavelength division multiplexed passive optical network can effectively utilize the huge fiber bandwidth resource. However, it cannot achieve the goal of low-cost wavelength colorlessness and flexible multilevel spectrum splitting. Therefore, the time and wavelength division multiplexed passive optical network(TWDM-PON) with the characteristics of more accessing users, wilder coverage and larger bandwidth capacity has become a popular solution of the next generation passive optical network. In TWDM-PON, the wavelength and time slot should be simultaneously considered, thus the resource scheduling is crucial to the transmission performance. Therefore, combined with the characteristics of TWDM-PON, the users' differentiate demands on quality of service and the problems of bandwidth resource sharing are taken into account. In this thesis, a hybrid resource scheduling algorithm with traffic differentiation and a hybrid resource scheduling algorithm based on slide cycle are proposed to reduce the network delay and enhance the channel utilization ratio.Due to the characteristics of long reach and wide coverage in TWDM-PON, the round trip time of exchanging messages between optical line terminal(OLT) and optical network unit(ONU) becomes very long, that results in the severe deterioration of the delay performance of high priority traffic. In order to solve such issue, a novel hybrid resource scheduling algorithm with traffic differentiation is proposed. Firstly, the wavelengths of ONU groups are adjusted in real time to achieve resource sharing. Secondly, traffic sub-cycles are dynamically divided in accordance with the network load for the purpose of differentiated traffic. Furthermore, an online scheduling and an offline scheduling are designed to fill the wavelength voids and ensure the efficiency and fairness of resources scheduling respectively. The simulation results show that the proposed algorithm can satisfy the delay requirements of different priority traffic, guarantee the quality of service and improves the channel utilization ratio.Due to the low bandwidth utilization ratio and the different available time of wavelengths in TWDM-PON, a hybrid resource scheduling algorithm based on slide cycle is proposed. To meet the delay requirement, the sliding cycle is set dynamically according to the polling time of ONU. Meanwhile, in order to realize resource sharing and determine the authorized size of each ONU, the sharing bandwidth of resource pool should be calculated in real time based on the sliding cycle. Furthermore, in order to improve the channel utilization ratio, the ONUs in the resource pool are scheduled in advance based on the available moment of different wavelengths and the differentiate round trip delay. The simulation results show that the proposed algorithm can effectively avoid the waste of resource, reduce the average packet delay and effectively improve the channel utilization ratio. |