The Study Of Bandwidth Scheduling Architecture On IEEE802.16 Protocol

Recently, with the rapid development of information industry, wireless communication is playing more and more important role in people's lives,BWA(broadband wireless access) technology which is an important part of wireless communication technology also has extensive applied foreground and huge development potential. IEEE802.16 is a kind of BWA technology which is used in WMAN(Wireless Metropolitan Area Networks), it can provide BWA with more wide area and higher rate. As one wireless access technology, it will be more flexible especially in area where there is a lack of basic infrastructure. IEEE802.16 standard specifies the air interface, including the physical(PHY) layer and the medium access control(MAC) layer. The MAC layer of IEEE 802.16 is connection-oriented, service of various types has different Quality of Service(QoS) parameter, so the MAC layer can provide QoS guarantee for different services. Bandwidth scheduling in MAC layer is one of the most important part in implementing QoS guarantee, so whether an efficient MAC layer bandwidth scheduling architecture—including the appropriate scheduling algorithm and scheduling strategy—can be used is very important. IEEE 802.16 standard doesn't specify the bandwidth scheduling in detail, so it's a meaningful topic to discuss the MAC layer bandwidth scheduling.Around the question of bandwidth scheduling for 802.16 protocal, the paper introduced characteristic and development trend of various wireless access technologies and the background and research status for IEEE802.16 standard firstly. And then it introduced the overall structure of 802.16 protocal, focuses on Common Part Sublayer(CPS) which is one of the three sublayers in MAC layer protocal. The paper discussed the common scheduling algorithm in wired network and wireless network and analyzed the performance and characteristics of various algorithms and compared the performance of various algorithms in wireless network nextly. Then the paper studied the QoS architecture and service of various types defined by QoS architecture and analyzed the characteristics of the service of various types and which scheduling strategy should be used. The paper also studied some important scheduling architecture in the past.At last, according to above research, the paper proposed an efficient integrated bandwidth scheduling architecture based on Grants per Subscriber Station(GPSS) which can meet the QoS requirements of real-time service better. The scheduling architecture which mainly includes upstream scheduler and mapper is based on GPSS bandwidth grant mode and adopts integrated scheduling strategy based on the priority of various service flows. It is mainly used in the system which includes many real-time services—especially when hard real-time service which is delay-sensitive require more bandwidth. The scheduling architecture can provide the appropriate QoS guarantees for the service of various different types which are defined by the QoS architecture and service real-time service better. However, it lose some of fairness for non-real-time—such as Best Effort(BE)—service with lower priority. The simulation results demonstrated that the proposed scheduling architecture can meet the QoS requirements of real-time service better compared with previous scheduling architecture. It can reduce delay and packet loss rate of real-time services obviously.