Design And Implementation Of High-speed Communication Link Physical Layer

With the current popularity and rapid development of modern Internet and wireless communications,and people 's requirements for transmission rates in the future,how to carry out more efficient and reliable transmission of user data on limited spectrum resources has become the research purpose and motivation of the key technologies of next-generation wireless mobile communications.Among them,OFDM communication technology can effectively combat signal distortion caused by frequency-selective channels because it uses parallel subcarriers to receive and transmit message data,and avoids inter-symbol interference in multipath fading channels by adding a cyclic prefix in front of the symbols.MIMO communication technology greatly increases the capacity of the channel and the speed of data transmission due to the use of space resources.The MIMO-OFDM communication system developed by combining these two wireless communication technologies with each other has gradually developed into a core technology in the wireless communication field,and has been adopted in many standards.This paper first describes the technical principles of the MIMO-OFDM communication system,and studies its general architecture and some key technologies in the system.Then this paper studies channel estimation and MIMO detection involved in MIMO-OFDM communication system.The differences between several common structures in pilot-based channel estimation and their corresponding suitable scenarios are analyzed.The channel estimation method widely used in single-transmit-single-receive OFDM is extended to the MIMO-OFDM link in this paper.The complexity and performance of common zero-forcing algorithms,minimum mean square error algorithms,maximum likelihood algorithms,and serial interference cancellation algorithms for MIMO detection are compared.Finally,zero-forcing detection algorithm with eight transmit antennas and eight receive antennas are chosen.Then this paper designs the implementation structure of the MIMO-OFDM communication link,introduces the division of the hardware modules of the transmitter and receiver,and illustrates the implementation of key calculations,mainly the calculation of matrix vector multiplication and matrix inversion.The complexity of several matrix inversion implementation algorithms is compared,and the Cholesky decomposition is selected as the FPGA implementation solution in this paper.Finally,analyze whether the results achieved by the FPGA meet the throughput requirements,and the communication link that meets the performance requirements is finally completed.