Study On The Dynamic Bandwidth Allocation Schemes In The Wireless-Optical Broadband Access Network

Wireless-optical broadband access network (WOBAN) is a novel network architecturewhich combines the bandwidth advantage of optical networks and the flexibility of wirelesscommunications. The WOBAN is especially suited to the situation of broadband access networkunder the current network background. However, due to the hierarchical structure of WOBAN, itis significant to design an applicable and efficient dynamic bandwidth allocation (DBA)algorithm for ensuring a data transmission between the wireless domain and the optical domain.In this paper, we propose a convergence of WiMAX and EPON for the structure of WOBAN.Under this application background, the paper presents an integrated and hierarchical QoS-awaredynamic bandwidth allocation (HQA DBA) framework, and investigates an HQA DBAalgorithm. In addition, we use network simulator with version2(NS2) to develop the simulationplatform for the HQA DBA framework and algorithm, by which we evaluate the performance ofthe proposed DBA algorithm.The main works in this paper are summarized as follows:(1) The paper presents a hierarchical QoS-aware dynamic bandwidth allocation (HQA DBA)framework. This framework takes charge of the deployment for the bandwidth allocation andschedule scheme in the WOBAN. The design of an integrated facility OBF (ONU-BS Facility)which connects the wireless domain and the optical domain is introduced in detail. In the paper,we also investigate a traffic mapping scheme, which takes charge of a smooth data transmissionbetween wireless domain and optical domain.(2) Based on the HQA DBA framework, the paper proposes a HQA DBA algorithm. TheHQA DBA algorithm takes into consideration the differentiated service of traffic with diverseQoS requirements in the network. The DBA algorithm supports bandwidth fairness at the OBFlevel and relative guarantee for class-of-service.(3) The paper uses network NS2to simulate and evaluate the performance of HQA DBA framework and algorithm. At first, the paper introduces an OWns module into the NS2tosimulate the optical network part of WOBAN. Furthermore, the paper investigates the way ofhow to embed the HQA DBA algorithm into the NS2platform. The simulation results show thatthe HQA DBA algorithm operates more effectively and efficiently than the Normal DBAalgorithm in terms of packet drop probability, end to end delay and network throughput. Inaddition, we compare the performances of diverse traffics when the WOBAN has been deployedwith HQA DBA algorithm. The results verify that HQA DBA algorithm can supportdifferentiated service to class-of-traffic.