Research And Modeling Of IEEE802.15.4MAC Protocol For Cyber Physical Systems

As computing, internetof things technology, embedded network sensingtechnology and automatic control technology developing fast, after computers andthe internet, the new generation of intelligent systems-the Cyber-Physical Systemwhich integrated computation, communication and control in one body is expectedto be the third meeting of the information technology revolution in the world.Theresearch and the developments of the CPS have a great significance in speeding uptechnology, informational and intelligent in the field of various industries all over theworld.The IEEE802.15.4, as its energy efficient and robust as it does in the physicallayer, and its flexibility in media access control sub-layer, it become the commonunderlying communicationprotocols for WSN.Selecting the current widelyusedIEEE802.15.4as the underlying wireless communication protocols of WSANsinCyber-Physical System can offerbetter solution which can meet the standardspecification, low complexity and low cost.In order to provide differentiated quality of serviceguarantees, improve thenetwork’s adaptability and bandwidth utilization, reduce delay and packet loss, andmake the network performanceoptimization to satify the application demandsofCyber-Physical System, this paper not only modelingthe MAC layer ofIEEE802.15.4protocol, but also further study the GTS mechanisms and the slotCSMA/CA of its MAC.The main work of the thesis includes the followings:1. Firstly, this paperdeeply analyzesthe IEEE802.15.4protocol. On the basis offullyunderstanding this protocol, with the OPNET, IEEE802.15.4node model havebeen bulit. For the lack of analyzing multi-slot GTS performances, with the networkcalculus, then the paper analyzes the service curves of delay bound and throughput,and the connection with energy consumption.Model and simulate to study how GTSparameters influenced the network performances, and offersomevalidviewsofoptimization configuration references while CPS-related scenes use themulti-slot GTS. 2. For an unbalance handicap between bandwidth utilization and data rate,usingnetwork calculus to compare and analyze, then proposesan adaptivebalance GTSallocation scheme (A-BGAS).According to the data flow information and the valueof super-frame order, A-BGAS can adjust slot precision and the allocated slot sizeadaptively.It can guarantee delay bound while improve the bandwidth utilization,and meet the QoS requirements under real-time application of CPS.3. For the requirements of different application in CPS, a priority-based dynamicand adaptive service differentiated mechanism(DASD-CSMA/CA) algorithm isproposedand the corresponding Markov chain model is analyzed. According to thetime-delay sensitive degrees of variousapplication informationflows inCyber-Physical System, the DASD-CSMA/CAmechanismimportsthepriorityschematosupplydifferentiatedservices. The different priority nodes usedifferent protocol parameter configurations, and adjust the back-offindexdynamicallyto adaptive network conditions.4.Finally, A-BGAS mechanism and the DASD-CSMA/CA algorithm arerealizedand simulatedin OPNETrespectively. The simulation results indicate thattheA-BGAS mechanism can improve about25%of network bandwidth utilization, andmeet the QoS requirement of bandwidth in CPS. Thenthe algorithm ofDASD-CSMA/CA has a strong network adaptive capacity, andcan better meet theQoS requirement ofvariousapplication data flow.This has profound significancevaluein designing and improvingMAC Protocol for wireless sensor networks inCyber-Physical System.