Research On Communication Middleware Technology Based On Data Distribution Service

With the continuous development of information technology and communication technology,the network environment becomes more and more complex,and the scale of signal data increases exponentially and the data sources become more and more extensive.Due to its limited scope and computing resources,the traditional signal processing system has been unable to handle the massive signal data flow in the complex network.In order to cope with this challenge,the signal processing system gradually transforms from the traditional independent dedicated platform to the distributed comprehensive universal platform,which makes the distributed universal signal processing system with the characteristics of real time,modularization,reconfiguration and so on become the research hotspot.Distributed universal signal processing system is driven by data flow.In order to guarantee the real-time performance and high efficiency of the system,a suitable data transmission mechanism must be adopted in the system network.Data Distribution Service(DDS)is a kind of data-centered communication middleware technology.It has the characteristics of strong real-time,loose coupling and high throughput.It is a Data transmission solution specially designed for distributed real-time system,which fits the requirements of distributed universal signal processing system well.The main work of this thesis is to expand and transform Open DDS according to the requirement of distributed universal signal processing system,and help the system to enrich functions and improve performance.The specific work is as follows:(1)Distributed universal signal processing system needs a communication mechanism in the form of request/reply,which is used for service invocation within the system and interoperation between nodes,but DDS is not capable to deal with dealing with such a tightly coupled communication mode.Therefore,this thesis studies the Remote Procedure Call(RPC)mechanism based on DDS,and implements the request/reply call of system services,which is conducive to the modularization and diversification of system services,enriches the communication mechanism of the system,and saves the cost increased by adding new RPC middleware.(2)In the process of system signal processing,DDS middleware has the problem of insufficient bandwidth when transmitting small packets.High-frequency transmission of small data packets leads to frequent invocation of input and output ports,which leads to excessive participation of software and hardware resources at the operating system,CPU and other system levels.Serialized scheduling increases delay and hinders full utilization of network bandwidth.In order to solve this problem,this thesis proposes a solution of mass transmission,which is used as a Quality of Service(Qo S)strategy for the system.Simulation results verify the effectiveness of this strategy.(3)File is an important carrier for storing information of various services and application systems.There are many scenarios for file transfer and exchange between systems.DDS middleware only supports data flow transmission in the system,so it is necessary to expand the file transfer mode on this basis.Based on DDS middleware,this thesis implements an open-ended file transfer adapter,which supports large file transfer,file continuation,progress echo,integrity check and other functions.It expands the types of DDS transfer carriers and meets the requirements of the system for file transfer.