Design And Implementation Of TD-LTE Downlink Based On FPGA

With the rapid development of mobile Internet,the demand for high-speed data services of cellular mobile networks is increasing,which makes each terminal manufacturers,network equipment manufacturers and operators are actively accelerating the deployment of LTE networks.FPGA plays the role of glue logic in physical layer of traditional base station,but with the continuous improvement of FPGA technology,logic resources of the chip is constantly enriched and power consumption is reduced,which make a single FPGA be able to process the protocol stack of entire LTE physical layer,so development of physical layer protocol stack based on FPGA can save the interface development between FPGA and DSP,as well as projects integrated by multi-chip systems,therefore it can reduce costs and power consumption.The paper make an innovative design and implementation for TD-LTE physical layer downlink system based on Xilinx Virtex-6 FPGA development board and ADI FMCOMMS1-EBZ RF board.Downlink system consists of baseband protocol processing subsystem,RF subsystem and control subsystem,protocol subsystem complete design and implementation of protocol stack of downlink channel coding,scrambling and modulation,resource mapping and IFFT with CP insertion.By modifying the appropriate drive and interface functions of RF subsystem,and initializing and configuring RF board properly,which make the RF subsystem satisfy downlink transmission demand.Control subsystem mainly complete the design and implementation of the bus unit bridge which based on AXI bus protocol,calculate and cache configuration,distribute data and configuration to the protocol subsystem and RF subsystems,making the downlink system run stably and constantly under scheduling of control system.On the basis of adequate test of each module and subsystem in the system,then integrate each subsystem in SoC system to do system-level test over the air,and the results verified the accuracy and robustness of downlink system.