The Implementation Of The Real-Time Transmission On The Platform SDR-LTE

With the rapid development of the mobile communication technologies, some communication networks such as the2G,3G, LTE coexist with each other. But mobile communication devices have poor performance in multimode support, functional extension and compatibility. So the Software Defined Radio which is called SDR, the solution of this kind of problems, is being paid more and more attention by the industry and academics. Recently, with the rapid development of the general purpose processor which is called GPP, it is increasingly powerful in processing data and the SDR scheme based on GPP has been widely studied and applied. Owing to the good application prospect in the high-speed computation, centralized baseband processing, code reusability and so on, SDR on the basis of GPP gains recognition by the industry and academics.However, the technologies of SDR on the basis of GPP in developing software and hardware are far from perfect, and we don’t have too much relevant technical data, worse still, the relevant practice of literature rarely gives comprehensive analysis in the feasibility. Therefore, the thesis expounds the research and application process on the GPP-based hardware platform SORA for the application of the high-speed wireless communication protocol, LTE, aiming to providing application reference and practical value for the research and development of the GPP-SDR. In order to distinguish from other kinds of applications, we take SDR-LTE for the name of the equipment including software and hardware, which also called based station. This thesis first gives an outline of the SDR-LTE, a soft base station platform and then gives a detailed introduction of the related technology from two aspects of software and hardware, introducing the logic structure and data processing.To solve the long-standing problem of timing deviation of the SDR-LTE, the thesis provides the timing compensation and correction scheme and has solved the data dislocation due to the timing deviation, improving the system robustness. To solve the lack of the functional support for the time division duplex, the thesis puts forward a set of reading schedule on the basis of a particular access structure, realizing efficient data reading scheme and reducing the computing resource consumption. To make up for the disadvantage of time consumption of LTE in modulation and demodulation, the thesis applies a reasonable variable control and structure adjustment based on the real-time requirements and actual resource consumption of the function module, which has improved the performance of SDR-LTE in real-time processing and solved the confusion among the multithreading, also reduced the requirement for algorithm efficiency for modulation and demodulation process. On the basis of the research above, we have realized the continuous and stable two-way transmission experiment on the SDR-LTE.To verify the feasibility of SDR based on GPP in the field of wireless communication, the thesis demonstrates a business of real-time video streaming, and gains a great success. To minimum the influence of the wireless transmission delay between the two SDR-LTE soft base stations, this thesis adopts a data transmission schedule of multiple retransmission queue and has solved the retransmission failure caused by huge delay.Thanks to the study above, we have built a SDR-LTE soft base station. It can support for20MHz bandwidth,100meters (or more) transmission distance,44Mbps peak rate, and to our delight, our achievement has passed the measurement an assessment taken by the independent third-party testing and evaluation organizations.