Design And Implementation Of The High Speed Data Real-time Transmission Software Based On The Embedded Multi-thread

Nowadays, the application of embedded real-time communication equipments is becoming more and more common, especially in the field of military and other special situations. As the important part of a real-time communication system, the data transmission software located in the application layer of the embedded system, which is responsible for the two-way transmission of data within the communication equipment, has a great significance to the communication quality for its reliable and efficient function of data transmission. The data transmission software is often facing some challenges in the design and implementation:(1) Multi-task management: need to design the program structure which is suitablefor the complex communication environment, and solve the problems such asresource access controlling, scheduling and synchronization.(2) Data transmission: need to realize the reliable, real-time transmission of a largeamount of data, without affecting the performance of the system.(3) Software performance: need to manage the limited resources of embeddedsystem to ensure the program performance, and to maximize the degree ofgenerality and modularization for easy transplant and changing.In this paper, a kind of real-time data transmission software is designed and implemented on the independently developmented handheld communication platform, which is based on embedded multi-thread, multimedia codecs, and high speed data transmission technology after extensive research of present data transmission softwares, and is tested by a large number of tests on function and performance.Firstly, combined with the application scenario and hardware conditions, the function and performance demands of data transmission software on handheld communication platform are analyzed in detail. According to the demands, the implementation plan is designed using the top-down method: Firstly plan the multi-threaded software structure according to the overall software framework, and divide the software into master thread, upward thread and downward thread; Secondly, design the interacting ways between main threads and child threads based on the principle of modularization; Finally, design the file, audio, and video transmission module respectively, according to the demands of communication function.Secondly, the data transmission software is implemented on the basis of the design: realize the master thread, upper and lower parallel threads, each subroutine thread, and multithreading interaction, management and synchronization between them using embedded multi-thread, mutexes, condition variables, and thread array method; Use audio and video codec technology, DMA(Direct Memory Access), the double data buffer mechanism in the realization of the software for audio, video, and file data transmission, with the operations of the other processes in the system are not affected; In addition, the memory allocation and release modules are designed for the unified management of memory resources.Finally, the software function test and performance analysis are conducted: first of all, in a single end, the DMA module, data transceiver interface, the audio, file, and video modules are tested respectively, to verify the function of data reading and writing; Secondly, in the actual communication scenario, audio, files, and video communication are tested, proving that the data transmission software can meet the requirements of real-time communication; Finally, the software performance testing and analysis are done, and the transmission quality is verified by analyzing the rate of each phase in the transmission.The real-time data transmission software designed in this paper is able to complete reliable, real-time transmission of all kinds of data in the system, and has advantages of high versatility, cohesion, and modularization, and is easy to reuse and modification.