In this letter, firstly, a novel adaptive beamformer using independent component analysis (ICA) algorithm is proposed. By this algorithm, the ambiguity of amplitude and phase resulted from blind source separation is removed utilizing the special structure of array manifolds matrix. However, there might exist great calibration error when the powers of interferences are far larger than that of desired signal at many applications such as sonar, radio astronomy, biomedical engineering and earthquake detection. As a result, this will lead to a significant reduction in separation performance. Then, a new method based on the combination of ICA and primary component analysis (PCA) is proposed to recover the desired signal's amplitude under strong interference. Finally, computer simulation is carried out to indicate the effectiveness of our methods. The simulation results show that the proposed methods can obtain higher SNR and more accurate power estimation of desired signal than diagonal loading sample matrix inversion (LSMI) and worst-case performance optimization (WCPO) method.

In this letter, DFT-based channel estimation (CE) with a strong interference detector is proposed for OFDM systems. Computer simulations demonstrate that the proposed scheme achieves similar performance to an interference-free system and is a significant enhancement over conventional methods.

A space-time RAKE (ST-RAKE) receiver with a blind interference-blocking (IB) pre-processor, termed as the IB-RAKE receiver, is proposed for spread spectrum communications systems. The design of the proposed architecture consists of three components. A blind IB transformer is first constructed based on the received data, and then applied on the undespread data for the suppression of strong interference. After despreading, optimal beamforming is then performed on the IB despread data to extract the signals of interest (SOIs) from the desired user. Finally, a RAKE receiver with a maximum ratio combining technique is employed to constructively collect all the SOI energies. Since strong interference has been removed in the first stage, the RAKE receiver combines only those SOIs plus negligible interference, leading to robustness against strong interference. Numerical results have shown that substantial improvement can be obtained from the proposed ST-RAKE receiver with the blind IB pre-processing scheme.