Research And Implementation Of Wireless Medium Access Control Method Based On The Remaining Delay

Wireless local area networks are being widely deployed, and quickly applied to many different environments, such as business, family and public access networks. At the same time, the application of voice, video and other multimedia services are also increasingly widespread. However, multimedia applications require the network to provide a certain quality of service(Qo S) features, such as guaranteed bandwidth, low latency and jitter. Therefore, how to enable the network to provide Qo S requirements become a key issue. Compared to traditional wired networks, Qo S support for wireless networks is more challenging. In addition to the inherent cause of wireless transmission medium, the medium access control(MAC) protocol is an important factor in causing network performance bottlenecks. Therefore, the study and improvement of wireless media access control, and thus enhance the Qo S of wireless networks, has very important significance.IEEE 802.11 wireless network standard is currently the most widely used, and distributed coordination function(DCF) is its most basic access. However, with the increasing multimedia services, it fails to provide Qo S guarantees. Thus, a new standard has been proposed, i.e. 802.11 e, its primary access for Enhanced Distributed Coordination Access(EDCA). It distinguished services according to different types.In essence, with Qo S guaranteed wireless medium access protocol should prioritize the more urgent packet. However, due to the paths differentiations and dynamic wireless transmission delay, even if belonging to the same type of data packet may be different for the time urgency.Therefore, we propose and implement a wireless medium access control method based on the remaining delay of packets, namely D-MAC. In D-MAC, the stations calculate the remaining delay for local stay according to the remaining end to end delay and packet routing state, and to determine the position in the buffer queue according to the packet. Comparing to the local stay remaining delay of the next packet determines the interval frame spaces and contention window of the station. The smaller the local stay remaining delay value of the packets, the greater probability to access medium, then the more urgent packets have a greater chance to send. Compared to the 802.11 DCF and 802.11 e EDCA, our simulation results show that D-MAC can significantly improve system throughput and average access delay.