Adapative Polling Sechme On IEEE 802.11 PCF

With the rapid development of information technology, especially the extensive application of powerful portable computers, personal digital assistants, as well as multimedia terminals, People will greatly promote the personal information and communications technology needs, and the related technology will be updated day by day. People were no longer satisfied with the wired computer networks in communication between fixed terminals, but expect the multimedia includes data, voice, images etc. can be integrated for expanding wireless communications network. Then the portable computers surfing on the wireless net can be achieved, namely, mobile computer communication. In the background of this, the wireless LAN came into exists. As one of the important technologies to build mobile computer networks, it represents the direction for communications network technology development of the 21st century, and attracts lots of attention from all over the world. As modern communications and computer technology, the study of wireless LAN technology will be gradual improved, and further change the way people working and living.The newest IEEE Std 802.11documents were published by IEEE in Oct.1999.The characteristics of Medium Access Control (MAC) layer and Physical layer for Wireless Local Networks (WLANs) are specified in this standard. The effective spectrum technology physical layer units may be adopted in the design of MAC unit. The study of communications protocol is not easy in communications technology research and development. It is very significant to study the IEEE Std 802.11 which will make us able to possess the wireless network products by ourselves with independence intellectual property rights. Meanwhile, we will be able to grasp the basic research methods and general communication protocol process.The accomplished work on the topic "Adapative polling scheme on IEEE 802.11 PCF " as follows:(1) The latest achievements about PCF Scheduling Algorithm by the experts abroad were completely summarized. It includes Round Robin,Modified Round Robin,First-In-First-Out,Cyclic Shift Polling Scheme,Cyclic Shift and Station Removal Polling Scheme,Priority Polling,Aging Priority Round Robin Scheduling etc. . Each algorithm of them was briefly summarized.(2) On the basis of the existing PCF schemes, a complete adaptive deficit round robin polling sheme was proposed as well. The general agreements of NS-2 simulated telecommunications were summed up. Meanwhile the adaptive deficit polling scheme was simulated and experimental verified with the NS-2 simulation software platform.(3) The system configuration parameters of NS-2 software simulation platform were proposed for the final results of the algorithm, and the simulation algorithm was compared with the traditional Round Robin algorithm by the qualitative analysis.