Research On Sychronizaition Technology Of Beamforming Antenna

Compared with traditional antennas,beamforming antenna has better directivity,lower interference noise,and flexible self-adaptability.Therefore,it has drawn more and more attention from academia and industry field.But beamforming antenna also leads to some new challenges in synchronization.The narrow beam provides the advantages as security and anti-interference,but it also makes the direction alignment difficult in the initial synchronization,resulting in the long delay in link acquisition;the beam angle becomes a basic information to build a communication link in beamforming,so an effective synchronization algorithm of beam angle is necessary;in directional communication,the errors in antenna array may lead to the failure of beamforming and the angle errors of beam significantly decrease the SNR,so there are some new challenges in synchronization algorithm.In link acquisition,the thesis proposes a link parameter estimation algorithm by using omnidirectional frame based on GMSK modulation.It avoids the difficulties of neighbor discovery in direction pattern and the unbalance of power between direction pattern and omnidirection pattern.This thesis designs a novel synchronization algorithm of GMSK to obtain a better estimation range than traditional algorithms.And it's satisfied the demands of beamforming system.According to the simulation results,it's a conclusion that the proposed algorithm has better accuracy than traditional methods,and it's robust in message collision scene.This thesis studies on the fast synchronization algorithms of beam angle and proposed a beam angle estimation method based on sequence design.The beam angle is marked by the special structure and patterns of sequences.And combined with the sequence detection algorithm,the beam angle can be estimated.Comparing with traditional DoA algorithm,the complexity and the cost of computation in hardware is decreased and the efficiency of beam synchronization is increased.The effectiveness of proposed algorithm is proved by simulation results.In order to solve the synchronization issues in broadband system,the thesis proposes a synchronization approach in antenna array to eliminate the interferences on beamforming algorithm caused by the amplified and phase errors between array elements.The amplitude and phase errors are analyzed by mathematical modeling.Then,the synchronization approach of amplitude and phase in UCA is proposed.The simulation results show that the approach has enough estimation accuracy.Then,the thesis researches on the OFDM synchronization in directional communication.The proposed synchronization approach is optimized to fit the low SNR environment caused by the angle errors of beam.The simulation shows that the proposed algorithms have great performance in low SNR situation.