Research On QoS-guaranteed Packet Scheduling Technology In Hybrid Optical- Wireless Broadband Access Networks

Hybrid Optical-Wireless Broadband Access Networks(HOWBANs)have been proposed as promising solutions to provide customers with high-capacity,reliable,flexible,and ubiquitous services,which take full advantage of merits from both optical communications and wireless communications.In fact,packet is the unit of traffic transmission in HOWBAN.According to the quality of service(QoS)requirements and transmission direction of the packets,designing a reasonable resource scheduling strategy for the packet is very important.Therefore,based on the characteristics of HOWBAN network structure,a QoS-aware packet scheduling strategy and a load balancing virtual access network mapping strategy are proposed to make full use of the network resource and improve the quality of service of the packets.Either the resource scheduling strategies in HOWBAN do not fully consider the integration of HOWBAN to make their performance not superior or they can not distinguish the priority of traffic to make them difficult to guarantee the quality of service.In order to solve the problem,a QoS-aware packet scheduling strategy is proposed.Based on the ant colony optimization,a novel optimal routing algorithm is designed to improve the performance of network,such as delay,throughput and packet loss rate.Meanwhile,the method of interleaved polling between online optical network unit group and offline optical network unit group is utilized to fill the idle time between the two consecutive cycles.Furthermore,the amount of new arriving packets for all optical network units between the two consecutive cycles should be reasonably estimated,and bandwidth allocation for optical network units should be dynamically established.Then the packet scheduling strategy is completed to further reduce the average waiting time for traffic packets at the optical network units,which in turn optimizes the routing.Numerical results demonstrate that the proposed strategy can reduce the average packet delay and improve the resource utilization.In order to improve the network resources utilization of HOWBAN and solve the problem of poor coordination between the virtual node mapping and link mapping in HOWBAN,a load balancing virtual access network mapping strategy is proposed.A bandwidth segmentation model is established to divide the bandwidth of the joint links of the available paths between the access point and the gateway.We take the available bandwidth of the path,the average length of the path and the CPU capability of the gateway as the influencing factors to obtain the utility value of the subnet carrying.Then the virtual access network mapping is achieved based on the subnet with the maximum utility value.Numerical results show that the proposed strategy can effectively improve the acceptance rate of virtual access network,increase the virtual network revenue,and improve the utilization of network resource.