Ofdm Test System Based On Spectrum Aggregation Dsp Implementation Technology Research

A high data capacity is required in the future wireless communication with thelimited spectrum resource. Spectrum aggregation technology is a candidate technologythrough extending multiple continuous or discrete bands into a wider band to enhancethe capacity.Orthogonal Frequency Division multiplexing (OFDM) technology is robustagainst the frequency selective fading by dividing the frequency selective channel intomultiple flat sub-channels. This thesis studies and analyzes the above technologies, andthen completes the design of digital signal process and the test of system based on thespectrum aggregation technology and OFDM technology together.A common hardware platform containing two DSP chips and a FPGA chip isutilized as a test system in this thesis.On the one hand, the collaborative controlmechanism through the PC and the serial port is used at the upper layer. On the otherhand, the system design and implementation is completed by the hardware and softwareframework of DSP chip and FPGA chip in the bottom layer. The signal processingincludes the following steps in the transmitter. The data is generated by PC, and thendata packet is transmitted from FPGA to DSP by serial port. After completing the signalprocessing through DSP in the bottom link, the data is transmitted to FPGA.Eventually,data is sent out by radio frequency. The signal processing in the receiver isa reverse process.Based on the principle of improving the utilization ratio of hardware resources,thesis proposes current simply interface program by comparing many other programs–aseparate DSP chip is charge of transmitering or receivering data.thesis researches andrealizes the interface between FPGA chip and DSP chip, the interface between serialport and FPGA chip, the interface between two DSP chips.This thesis studies and analyzes the OFDM technology including the subcarriermapping, channel estimation, balance and so on. Firstly, digital signal process iscompleted on MATLAB software platform, theoretical analysis and simulation resultsshow that the system based spectrum aggregation technology and OFDM technology isfeasible. Then, this thesis completes the design and realization based DSP chip. Serial port selects seven channel spectrum aggregation units whose channel condition is goodaccording to the feedback information.DSP chip maps the corresponding data to theseven channel spectrum aggregation units. Aggregation baseband completes channelcoding, modulation, and symbol processing. At last, data is transmitted afterup-conversion and combination. The Receiver experiences a reverse process.In order to test the system performance fully, this thesis also conducts an indoorwired testing for the system. The simulation results are reported and analyzed in theindoor environment such as direct connection, Gaussian channel and fading channelenvironment by using the channel simulator. Indoor test results are compared with thesimulation results on MATLAB software platform and the gap of bit error rationbetween system and MATLAB is rational. The test can prove that this wirelesscommunication system is feasible and correct.