The Research On LTE-A Downlink And Implementation Of Multi Core DSP

LTE(long term evolution) is the ITU-R(ITU Radiocommunication sector, one of the International Telecommunication Union radio communications sector) specified in the fourth generation mobile communication technologies, LTE upgrade version of LTE advanced meet the rules for IMT advanced static transmission rate of 1GBIT / s, highspeed mobile state under 100 Mbps technical indicators. LTE/LTE-A as the world’s largest carrier to deploy and the most extensive mobile network system, in the future with unlimited technical potential. Take a look at the world, the LTE patent dispute, technical competition and the game of interests of the curtain is also being launched. Based on this background, this thesis begins to work.First of all, the object of this thesis- LTE downlink technology analysis, detailed the LTE network system architecture, and from the control point and the user side of the point of view of the LTE network protocol stack architecture. Then analyzes the LTE downlink channel structure and the mapping between the physical channel and the transmission channel. Then the frame structure and the resource block are described in detail in the LTE. According to the downlink processing mechanism of LTE, the signal coding technology of LTE is analyzed and the program flow is designed. In the LTE protocol stack of the physical layer to provide transport services, so this thesis designs the physical layer and the high-level protocol stack transmission mechanism to ensure that the message transmission mechanism is highly efficient and reliable. As the first step of UE’s LTE system, the thesis describes the mechanism of cell search, and designs its state transition mechanism, and then analyzes the key characteristics of LTE-A carrier aggregation technology.Secondly, in upgrading of mobile communication, base station deployment of upgrading most waste manpower and material resources, the baseband chip as a core component of physical layer functions, implement the custom application specific integrated circuit(ASIC) can not solve the problem with LTE standard upgrade and flexible upgrade. Therefore, high performance multi-core DSP scheme can upgrade and flexible expansion characteristics to solve this problem. In this thesis, based on the Chinese Academy of Sciences Computing Technology Research Institute research baseband chip for the realization of the project follow-up. Firstly, the thesis introduces the baseband chip architecture and the baseband board frame structure, then the design of the physical layer control system of state machine, DSP nuclear interaction mechanism, baseband data stream. After analyzing the difference between the two scheduling schemes, the static scheduling scheme is selected. According to the characteristics of double master control, the task allocation and task flow of the control system of the physical layer are designed, and the software programming framework is described.Finally, from two aspects of VCS tools simulation verification and platform verification, the work of the system is verified, and then the performance of the system is evaluated. The results show that the whole system is stable and reliable. Through the base band control system to the internal execution unit and the resources reasonable scheduling, has promoted the multi core DSP multi- duty processing efficiency, has fully played the baseband chip performance, has completed the initial system design realization.