TD-LTE Link-Level Simulation System Based On Software Radio

3GPP Long Term Evolution (LTE) project has officially become the4G standard, and as time progresses, the business based on4G LTE technology will also continue to expand globally. Due to the introduction of new air interface technology:orthogonal frequency division multiplexing (OFDM) technology, the spectral efficiency of LTE system has been greatly improved; and with the combination of MIMO technology, which greatly improves the signal throughput, LTE systems compared to3G standards, has greatly improved system performance. Because of the advantages of LTE system, a lot of research and exploration based on LTE system have been raised, such as LTE-A, Unlicensed-LTE, Small Cell etc. And many new systems and concepts have been proposed. Today, most of the study on LTE systems rely on the LTE simulation platform. The efficiency and performance of simulation platform will directly affect the results and progress of study. In order to improve the efficiency and accuracy of the LTE system study, this paper designs a new TD-LTE link level simulation platform.This paper analyzes the characteristics and deficiencies of existing LTE link level simulation system, and for the shortcomings of existing simulation platform:simulation slower, less efficient, it is difficult to accurately restore real communication situations; designed a based USRP’s TD-LTE link level simulation platform simulation with high efficiency, flexible simulation methods, and can be completed quickly and accurately LTE link level simulation.About this article refer to3GPP LTE standard (mainly for version Release9), the research and design of the link level simulation of several design ideas and designs focus on the baseband signal processing algorithms, including:CRC code design, channel coding design, OFDM modulation\demodulation module design, downlink channel synchronization process design. Link Simulation design combines baseband signal processing, this paper designs a LTE link level simulation system implementation on the USRP devices allow TD-LTE signal USRP device through the wireless channel to transmit real. Compared with the average link level simulation system, the program has a high simulation efficiency, flexible baseband signal processing, to accurately reflect the current environment, the characteristics of the communication channel.Finally, this paper presents the USRP-based TD-LTE link level simulation platform for the link level simulation of simulation results, and the results were analyzed.