Research Of Base Band Cooperative Communication System Of Space-Time Block Coding Based On FPGA

The Cooperative Communication based on Space-Time Block Coding takes advantage of the technology of the Virtual MIMO and the Space-Time Block Coding. So it not only overcomes the shortcomings of the limitation of most mobile handset’s size and the difficult of multiple transmit antennas integrated in a terminal equipment, but also allow single antenna systems to reap the same spatial and time diversity gains of MIMO systems. Since the cooperative communication technique effectively utilizes anti-fading performance and can improve the capacity and transmitting rate effciently, it would become an important research area for the wireless communications in future.Firstly,the article studies the principle of coding and decoding about space-time block coding proposed by Alamouti in the two-transmit-antennas-and-one-antenna system and adopts cooperative diversity technique and diversity schemes. Focusing on discussing and analyzing the performance of BER and the schemes of cooperative communication based on space-time block coding, this paper uses Matlab to simulate the performance of BER and testify the influence of cooperative channel on the quality of communication. Secondly, in Xilinx’s integrated development environment ISE9.2i, then combined with Matlab, the programme and the main modules are designed by the Verilog HDL language, which contain the module of QPSK constellation mapping and demapping, the module of coding about space-time block coding, the module of maximum likelihood decoding, the module of maximum mean power estimation and so on. The simulation map of each module and the whole system is conducted to verify the correctness of the transmitter and receiver by Mentor company’s ModelSim SE6.0. Finally,well-designed program is downloaded to two FPGA development tools(Virtex-II Pro). The programme of two cooperative partners is downloaded to one and the receiving programme of base station is download to the other. Comparing to two source sequences and the decoding sequences of base station verify correct by using the oscilloscope, but many frames in front are correct and the back of some frames appear certain error. Thereforce, there is a need for optimizing designd programme, especially maximum mean power estimation and clock division leading to clock jitter and clock delay. The simulation and test results show that the simulation of each module and the whole system is correct about cooperative communication based on space-time block coding, but the test of system hardware appears certain error.