Fair Sharing Using Real-time Polling Service to Adaptive VBR Stream Transmission in a 802.16 Wireless Networks

摘要

The Worldwide Interoperability for Microwave Access system's (WIMAX, IEEE 802.16) broadband networks is an attractive solution for high-bandwidth wireless access network. In the context of a wireless broadband access network, the term open real-time access implies the ability of multiple service BS (base station) to share the deployed access network infrastructure to make available to the SSs (subscribe Station). This paper contains brief variable rate control strategies for real-time multimedia VBR (Variable Bit Rate) service frame over IEEE 802.16 broadband networks. A data rate control mechanism is derived for the case where the downlink channel provides real time polling bandwidth allocation service while keeping the traffic rate parameter constant. The paper shows that common queue scheduling algorithms have some bandwidth allocation fairness problems for real time polling under the WIMAX system (IEEE 802.16) MAC layer. In other words, the use of a VBR real-time polling service by a WIMAX system results in additional access latency jitter and bandwidth allocation disorder in the transmitted variable data rate of a multimedia stream, during the base station's regular time interval polling of Subscribe Station (SSs) for the contention bandwidth request period. However, this scheduling algorithm solves SSs contented bandwidth resource problems, depending on the real-time polling service (rtPS) quality of service function under ranging response non-contention polling period, as the adopted fairness bandwidth allocation max-min algorithm is the only time constraint condition for transmitting real-time multimedia video or VOIP in the 802.16 wireless broadband environment. In addition, we utilized an NS2 simulation to analyze VBR stream capacity, and show that the extended-rtPS by fairness Max-Min algorithm can support more multimedia stream users than other rtPS scheduler algorithms.