Design And Development Of Uplink Radio Resource Allocation For MAC Layer In IEEE802.16 Wireless Communication Systems

With the development of wireless communication and the emergence of fresh multimedia services, broadband, wireless, and multi-service have become a tendency in communication network. IEEE802.16d/e technologies that define an air interface of broadband wireless metropolitan area network (WMAN) are one of the hottest broadband wireless access (BWA) technologies because of its high-bandwidth, low-input and well QoS support. There are physical layer (PHY) and medium access control layer (MAC) in IEEE802.16d/e, and radio resource allocation (RRA) which determines the channel utilization of the system and the QoS satisfaction of users is one of the key technologies in the MAC layer. IEEE802.16 Base Station (BS) WiMAX system contains Uplink (UL) RRA and Downlink (DL) RRA , but this thesis will mainly focuses on the UL RRA scheme in it.By analyzing the IEEE802.16 QoS mechanism, we proposes a priority-distinguished and Channel-related UL RRA algorithm, which considers the types of services, the band requests of the Users, the QoS of the connections, and the quality of the UL channels synthetically. Firstly, the algorithm arranges the connections to be scheduled in priority order according to their bandwidth allocation type, service type and service transmition parameters. The connection with higher priority will be scheduled first. Secondly, the algorithm selects the modulation and encoding type for each user based on their channel status to improve the system throughput and reduce the packet error rate. Thirdly, the algorithm designs various of allocation schemes for different scheduling type, they are: Spiraled scheduling method with similar grant interval for UGS services; Dynamic grant scheduling method with similar grant interval for ertPS services; Scheduling method based on the improved Earliest Deadline First (EDF) algorithm for rtPS services; Token bucket scheduling method based on the Round-Robin (RR) algorithm for nrtPS services; Grouped scheduling method based on the barrel theory for BE services. This UL RRA algorithm not only could support multi-user and multi-service, but also improve the channel utilization, and satisfy the different QoS requirement of users as well.In order to apply UL RRA algorithm above to the actual system, we also design an UL scheduler and integrate it into IEEE802.16 BS MAC protocol software to validate the performances of this algorithm. The testing results show that scheduler can conform to the WiMAX Forum criterions—the UL throughput of the scheduler can reach to 6.8 Mbps, the data channel utilization is more than 96% in single-user mode, and the average roundtrip latency between BS and MS is 29 millisecond; The scheduler could support all services based on IP, such as VoD, VoIP, HTTP, FTP and etc, it also can fulfill the QoS requirement of the multi-media services; Moreover, in 32-user, 64-connection testing scene, the data channel utilization can maintain more than 80%.At present, the UL scheduler has been integrated into several research institutes and device manufacturers' WiMAX prototype systems.