Improved orthogonal projection adaptive beamforming by using reconstructed interference covariance matrix

When the desired signal is present in the training snapshots, the performance of conventional orthogonal projection (OP) adaptive beamforming degrades severely due to the desired signal cancellation effect. To overcome this deficiency, the improved orthogonal projection (IOP) adaptive beamforming by using reconstructed interference covariance matrix is proposed. In the proposed algorithm, the interference covariance matrix is firstly reconstructed by integrating the Capon spatial spectrum over a region separated from the desired signal direction. Subsequently, the jammer subspace is estimated, and then the adaptive weight vector is calculated using conventional OP algorithm. The simulation results show that the corresponding output signal-to-jammer-plus-noise ratio (SJNR) performance of proposed IOP algorithm is almost same with the optimum beamformer with the desired signal in the training snapshots. Therefore, the proposed IOP algorithm is significantly effective for the actual system.