標題: Performance Enhancement of Contention-Based Bandwidth Request Mechanism in IEEE 802.16 WiMAX Networks
作者: Chou, Shih-Fan
Liu, Jen-Hsi
Chao, Hsi-Lu
Guo, Tzu-Chi
Liu, Chia-Lung
Tsai, Feng-Jie
資訊工程學系
Department of Computer Science
關鍵字: WiMAX;best effort;bandwidth request;contention
公開日期: 2010
摘要: The IEEE 802.16 standard is a promising technology for 4G mobile networks. Though supporting versatile service classes, best effort (BE) service class is expected to dominate WiMAX networks, due to operational simplicity. One of bandwidth request mechanisms that subscriber stations (SS) can utilize to issue bandwidth requests (BW-REQ) for BE connections is contention-based random access. An SS starts a timer T16 when transmitting a BW-REQ. If getting a grant before timer expiration, the SS transmits data packets at the allocated time slots; otherwise it performs truncated binary exponential backoff process for BW-REQ retransmission. The default value of T16 is one frame time. However, T16 impacts on contention and request collision significantly. In the paper, we develop an analytical model for T16 timer setting. Besides, we derive analytical expressions for the average number of tries per BW-REQ and the average packet delay. We compare the theoretical results of fixed and adjustable timers. The results show that adjusting timer reduces both the number of collision and the average packet delay.
URI: http://hdl.handle.net/11536/18949
ISBN: 978-1-4244-8016-6
期刊: 2010 IEEE 21ST INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)
起始頁: 1287
結束頁: 1292
Appears in Collections:Conferences Paper