Research Of Adaptive Array Signal Processing Technology Based On OFDM Systems

OFDM multi-carrier communication technology is a typical representative of transmission technology is widely used in next generation mobile communication systems and a variety of broadband wireless access technology. Adaptive array antenna using array signal processing technology, dynamic adjustment of the array antenna beam, to eliminate or suppress multiple access interference with the frequency and improve the communication quality, and expand system capacity. OFDM system and the advantages of adaptive array antenna system can be subject to a wide range of concerns, combination of both is seen as a breakthrough in the field of mobile communications. Starting from the basic principle of this article, focus on the OFDM system synchronization, OFDM systems based on broadband beamforming technology, mainly as follows:Synchronization Technology. In this paper, a detailed analysis of the OFDM system synchronization technology and the adverse effects of bias based on the design of the training sequence used for system synchronization. The simulation analysis shows that the design of the training sequences using the system on the OFDM carrier frequency offset and phase shift can be well compensated, while the symbol timing synchronization can be done accurately.Pre-FFT beamforming technology. In this paper, based on training sequences and pilot signals for the reference signal of the pre-FFT beamforming algorithm analysis, and proposed a modified pre-FFT beamforming algorithm,The simulation results show that the improved algorithm can quickly converge and improve system performance, in the case of poor channel environment can maintain good performance.Post-FFT Beamforming Technology. In this paper, post-FFT beamforming algorithm subcarrier grouping method for the analysis and research, and proposes an improved algorithm, The simulation results show that the improved algorithm is closer in performance for the 2 subcarrier grouping algorithm performance, but the computation can be reduced.Composite beam forming technology. This is a relatively new system based on OFDM beamforming algorithm. The algorithm combines the time domain and frequency domain in the form of beamforming, The simulation analysis shows that the algorithm performance than time-domain beamforming improved a lot, although the performance slightly worse than the frequency domain beamforming, but its computational lower than the frequency domain beamforming a lot.FPGA design and implementation. This paper describes a simple FPGA design principles based on the chosen reference pilot signal for the OFDM system based on pre-FFT beamforming algorithm, Carried out the design and implementation of FPGA. Achieved through the function and the simulation shows that the design can meet performance requirements.