Research Of Wireless Bandwidth Allocation Algorithm Based On The Fairness And Transmission Efficiency For WiMAX

With the fast development of communication industry, network transmission ability has been improved a lot. Backbone network and high speed LAN are expected to be continuously updating with the increasing requests for bandwidth. However, how to design the access network connecting them becomes the bottleneck. With the advantages of flexible network-built, convenient network upgrade and maintenance, and high transmission speed, the WiMAX technology, an advanced broadband wireless MAN access technology based on IEEE802.16, has become one of the best technologies in the next generation broadband access network. WiMAX represents the latest trend of the access network, and it is one of the researching hotspots of current broadband access network. It is considered to be the main solution of broadband access in the future.IEEE802.16 standard specifies the air interface, and its medium access control (MAC) layer is connection-oriented. Service of various types in IEEE 802.16 protocol has different Quality of Service (QoS) parameters, so the MAC layer can provide QoS guarantee for different services. And the bandwidth scheduling in MAC layer is a crucial component of the QoS guarantee performance. But, it still remains as an open issue, since there isn't any bandwidth allocation algorithm specified or proposed in IEEE 802.16 standard. So it is a meaningful topic to research on. This paper mainly focuses on this issue and presents a suitable algorithm for IEEE 802.16 MAC bandwidth scheduling.Based on the characteristics of IEEE802.16 standard, in this paper a unite model based on utility function derived from IEEE802.16 service flows'bandwidth allocation is presented, and the utility-oriented bandwidth allocation algorithm based on the user's class and channel condition(named as UCC) is proposed. Then the bandwidth allocation is described by a nonlinear programming (NLP) problem which will maximize the whole utility of the system under some conditions. Due to the real-time need of practical application, a quick solution of the NLP problem is proposed, which can solve the problem by two steps: weighted water-filling and traffic shaping. The solution can lead significant decrease in computational complexity. The simulation results show that the UCC algorithm has evident advantages in both throughput and fairness compared with other algorithms which are already used in the IEEE802.16. It is also shown that because of its low computational complexity, the algorithm can be well met the delay demand of the different services'QoS.