The Asynchronous Multi-Channel MAC Protocol Research In Cooperative Network

This paper focuses on the multi-channel MAC design in the Cooperative Network. Based on the resources that multi-channel provided and the cooperative schemes,we give a comprehensive and intensive study on designing the proper handshake process as well as the format and storage of different information tables.The technologies of Cooperative Transmission and Multi-channel have been researched for years and already acquired high achievements, and the combination of these two aspects is an important area of research. For one thing,the cooperative transmission can increase the area of the network, enable a high velocity in transmission, and enhance throughput of the network; for another thing,multi-channel environment can directly provide more resources to users.Therefore, a properly designed multi-channel MAC scheme with the right information exchange method in a cooperative network have the ability to conquer the hidden terminal problem and share the state and resources information among all the users in the network and eventually results in a better performance.This paper gives the brief introduction of IEEE 802.11 protocol as well as the current research of multi-channel and cooperative transmission in the first place. The feasibility and benefit of the combination is also discussed.The hidden terminal problem is detailed and according to the analysis of some synchronous MAC design, we also analyzed some drawbacks of the category of synchronous MAC designs.Then the widely quoted asynchronous MAC design:CAM-MAC is discussed.Although it can solve the hidden terminal problem,it will inaccurately block the data channel reserves in some conditions,and this is called'redundant channel blocking'.A virtual path table can resolve this problem, as we presented in that chapter 3.The AM-MAC in cooperative network which is our emphasis in this paper has been fully revealed.In AM-MAC,four different tables are the basis of the negotiation process---each table serves for some specific functions and the formats of these tables have direct impact on the specific functions.For different nodes,the learning processes on the control channel are different,and the properly designed learning methods can help nodes acquire the overall information of the network. The overall handshake process is the crucial part of AM-MAC.The efficiency of the whole system relies on the handshake process.For the simulation part of this protocol,we considered different environments and evaluate the capability of AM-MAC from average network throughput and the average dropped packets number.The theory analysis and the simulation prove us that as a result of the properly designed multi-channel MAC frame and the handshake process combined with various information tables in cooperative network,the network capability improved in a great extent with the high throughput and less dropped packets.