Researches On Anti-interference Algorithm Of High Speed Communication System Based On Independent Component Analysis

The widely used OFDMA technology and the multi-cell multi-user massive MIMO technology for the future 5G mobile communication system are the hotspots research in the field of modern high-speed communication systems.Compared with the traditional modulation technology,OFDMA technology can greatly improve the transmission rate and bandwidth efficiency.But in a complicated electromagnetic environment,there always exit a variety of man-made malicious interference or co-channel interference.Thus,reducing the effects of interference on OFDMA system will be important.The massive MIMO technology use spatial multiplexing to improve the data transmission rate,thereby improving system capacity with the limited spectrum resources.However,the traditional MIMO system reuses pilot for channel estimation and decoding,which will inevitably introduce pilot contamination,so that the system performance degrades seriously.Therefore,how to address the pilot contamination has aroused more and more attention.In order to overcome the above problems,this paper proposed an anti-jamming algorithm based on independent component analysis(ICA)for OFDMA system and massive MIMO system.Firstly,an anti-jamming algorithm based on ICA is proposed to solve the problem that the performance of OFDMA is degraded due to the interference in OFDMA system.The algorithm models the received signal into a blind source separation model based on subcarrier matrix.The single-tone interference is modeled as a virtual user of the OFDMA signal.The subcarrier matrix demodulation is done by ICA,and the single-tone interference and OFDMA user information are separated to address the anti-jamming.The proposed method takes the interference signal as a virtual user in OFDMA,which separates the OFDMA signals and interference signal without removing the cyclic prefix(CP)and decoding.The new anti-jamming algorithm has a better performance than the traditional method,which is based on frequency domain filtering and removal of CP decoding.Secondly,for the pilot contamination due to pilot reuse in neighboring cells,this paper propose an ICA decoding method to overcome the pilot contamination in multi-cell multi-user massive MIMO system.The proposed decoding method firstly uses ICA to separate the desired signal from the interfering signal,and then the channel energy is used to differentiate the in-cell signals and the neighboring cells signals,and reference bits are applied to identify the desired signal among signals within the cell.Numerical results show that the proposed blind method has a better BER performance and higher transmit efficiency than the traditional minimum mean-square error(MMSE)decoding method and singular value decomposition(SVD)based decoding method with unknown channel state information.