Research On Centralized Control Of Airborne Wireless Network Access Technology

In recent years,with the application of Fiber Channel technology in avionics network,the improved communication bandwidth and anti-electromagnetic interference capability has met the large capacity,time sensitive and high reliability demand of integrated avionics system.But the current avionics network of fiber and cable transmission,still faced with heavy weight,expensive,not flexible connection,wiring complexity,line fault detection is difficult,is not conducive to system expansion and many other issues.With the development of wireless communication technology,the transmission rate and the anti-interference ability of wireless network has improved.So the use of wireless network to achieve avionics equipment interconnect has become an important development trend of avionics network.Most of the existing wireless networks use CSMA in which wireless terminals access wireless network by free competition.CSMA can't guarantee that each message's delay meet the required maximum delay.To this end,by using the message scheduling mechanism and centralized control method,this thesis carried out the following work around the centralized control of airborne wireless network access issues.1.A centralized control airborne wireless access method based on message schedule is proposed in this thesis,which is based on the 1553 B scheduling mechanism and IEEE802.11 MAC layer PCF.In order to ensure that each message satisfies its maximum delay requirement,an adaptive fixed window length scheduling method is designed.The simulation results show that the method has the characteristics of delay guaranty and not losing packets.Aiming at solving the problem of wasting transmission bandwidth in idle time slot,a cycle scheduling method is designed after a single schedule in a small cycle,which use the idle slot to schedule other messages.The simulation results show that compared with the fixed window scheduling method,it has the characteristics of reducing network delay and improving the network capacity.2.Combining with the message list and message scheduling mechanism,a centralized control airborne wireless access method based on message list is proposed,to utilize the free time slot with no message sending in the message scheduling table scheduling.The simulation results show that the method has higher network load adaptability and lower network delay than the message scheduling method based on message scheduling table.3.An experimental test platform which uses message scheduling table and centralized wireless access technology based on message list is constructed.It is verified that the two scheduling methods can guarantee the maximum delay requirement of the messages.And the scheduling method based on the message list has a lower message average delay than by using message scheduling table.The centralized control airborne wireless access method designed in this thesis has the characteristics of ensuring maximum delay requirement of messages,without packet loss,low delay and large capacity.It can fully guarantee the real-time,deterministic and reliability requirements of avionics,also provides the basis for the design of airborne wireless network access control method.