A Token-passing Algorithm Improved Wireless Token Transfer Protocol

With the development of the wireless communication, the research of the wireless network based on wireless channel has become the focus in network domain. Ad Hoc wireless network is a multi-hop wireless network that has the characteristic of self-organizing, acentric and self-dependent. By other station's transmit, the two station who can not communicate can exchange information. Ad Hoc networks can be widely used in many area such as military, sensor network, personal area networks and emergency. Most research in Ad Hoc field is based upon MAC Protocol based on competitive mechanism who can not provide quality of service(QoS) at the MAC layer. Meanwhile, in the traditional cell network, the access point judge that the slave station have date to send or not by polling them, and the information exchange between two slave stations need the help of the access point. The research in wireless MAC protocols based on distributed poll mechanism which can slove the problem is important in some applications.A distributed MAC protocol with Quality of Service Guarantees for Ad Hoc network--wireless token ring protocol(WTRP) is introduced in this paper. This project impose justice, latency and fast the speed of failure recovery requirements on the media access protocol. To solve the problem, a novel medium access control protocol is proposed for wireless Ad Hoc network in this paper based on the old MAC protocol. The token dynamic transfer algorithm is presented which can adaptively choose next station to transfer the token without establishing a logic token ring in advance. Compared to WTRP, it choose the next station based on the topology and transfer the token or not. In a word, the new algorithm has a better adaptation to the change of the network topology, and simplifies the process of token maintenance. By using NS2 to simulate the WTRP protocol and the modified, the result shows that the performance of the modified is better than befor.