Design And Implement For Wireless Base Band Communication Systerm Based On FPGA

Currently, wireless network protocols have been leading the new revolution in the field of wireless network, they have brought huge impacts and great conveniences on human's life. OFDM (Orthogonal Frequency Division Multiplexing) technology, due to its longer symbol duration which is resistant to multipath effects, has been widely used in many advanced digital communication systems. In this case, how to realize efficient OFDM systems has been a very important issue for academic or industrial fields.In this thesis, a research and design method for wireless baseband communication system based on FPGA is proposed, especially for the key modules including of encoding and decoding for convolution code, adaptive constellation mapping and de-mapping, OFDM modulation and demodulation. Improve the traditional back tracking unit in truncated decoding module for convolution code, in the cost of small amount increasing in the implement complexity, making the performance closer to maximum likelihood decoding and increasing the reliability of communication. In addition, adaptive design based on the traditional constellation mapping and de-mapping module is proposed supporting BPSK, QPSK, 16QAM and other modulations according to the SNR estimated. In OFDM modulation and de-modulation, dual port Rams are used to accomplish the sub-carrier mapping of data and pilot signal sequence. Meanwhile, in order to make the performance of FFT/IFFT modulation better, method of adjusting amplification step by step is raised to optimize the fixed-point design. In order to verify the validity of system designed above, a semi-physical verification platform consists of FPGA and MATLAB is proposed in the thesis. MATLAB is used to model and simulate the front-end modules and channel condition, and the data obtained will import to the FPGA modules designed. In the OFDM wireless communication system constructed, point to point one-way communication is achieved, and the experimental results meet the design requirements which fully demonstrate the feasibility and validity of the system designed in the thesis.