Repeated Testing Random Multi-access Wireless Sensor Network Protocol Models

Random multiple access control protocols use a method that random access resources of user, competition, control flexibility, but also to ensure that the small number of users have a higher transmission efficiency, under certain conditions which have been able to occupied channel resources effectively, reducing the switching delay and other characteristics. Therefore, in wireless communications networks it has been used more and more widely. However, with the rapid development of modern technology. The traditional single-channel random multiple access control system performance dramatically deteriorated, collision probability of random users compete is increased, with the developing of the channel transmission efficiency variation, which will inevitably lead to in-depth research of multi-channel random access control protocol.In this paper, to study the wireless sensor networks, and put forward a number of random access MAC protocol with priority control, for example : ODMA and MDMA, performance is analyzed to illustrate its effectiveness. The study of these protocols make the way of control for multi-channels and multi-service more flexible and effective. It has a positive effect in the field.Thesis is divided into four chapters :Chapter I, first, introduced the history and development of random multiple access protocol, from the ALOHA, CSMA series. Then discussed the combination of random access technology and new technology. Mainly refers to multi-channel and multi-service and the combination of priority. Describes the application of wireless sensor. Focus on this thesis content source, proposing the article research topic.Chapter II, this chapter is the focal point. Random multiple access control protocols with once channel detected, the channel is idle when packet arrival is sent, and its mathematical modeling, using an average cycle approach to analyze. Discuss the average length of idle slot, busy cycle, the collision, the success and so on. On the basis, derived the formula of system throughput, throughput of each priority, delay. Finally, computer simulation of the theoretical value.Chapter III, this chapter is an extension of the second chapter, it is not only emphasis but also difficulty. On the basis of once channel detected, namely, combined with twice channel detection to make collision avoid. And its mathematical modeling ,using the average cycle method to analyse performance. Finally, on the basis of the repeating two chapters, devriving the throughput of many times channel detected. Through computer simulation(MATLAB) to verify the theoretical is correct.Chapter IV, summarized the full text of the main research work, discussed the problems in it and the direction of continue in-depth in future.