Research On Fast Beamforming Based On Multi-element Antenna

Array Antenna can be used to improve the system capacity and inhibit noise insatellite communication system, As the key technology of Array Antenna. Beamforminguses a certain shape of the beam to point to the expected direction of arrival wave inorder to improve the signal-to-noise ratio.In this paper, beamforming is achieved by estimating DOA (Direction Of Arrival)of the expected signals. The purpose of DOA estimation is determining the directionangle of each signal, then using the estimated direction angle. Beamforming can beachieved by adjusting the weight vector of each array element. The main researchresults are as follows:1. A cross planar array has been proposed. Planar array parameters are deducedby the estimated uniform linear array parameters for the purpose of fast beamforming.Based on the uniform linear array, DOA has been estimated, then the direction angle andpitch angle of the planar array can be calculated. This Array model can reduce thecomplexity of signal processing.2. The performances of Capon, MUSIC and DFT algorithms are analyzed andcompared via simulation. The results show that MUSIC and Capon algorithm has thehigher resolution. But both Capon and MUSIC are more complex to implement byhardware; The high resolution DFT algorithm which accuracy is moderate less incomplexity and can be implemented easily by hardware.3. A low-complexity fast beamforming implementation schema has been designed.First, the index of energy spectrum peak is obtained by low-resolution DFT using smallamount of snapshot data, then partial high-resolution DFT can be done using largeramount of snapshot data. The scheme shows that it can reduce calculation complexityand save hardware resources.4. The implementation scheme above is applied to the direct-sequencespread-spectrum system and key modules are designed on FPGA.