Optimum antenna combining in presence of TX leakage

Optimum antenna combining is utilised to cope with the transmitter (TX) leakage issue encountered in carrier aggregation. By assuming the transmission of pilot symbols and exploiting the structural information of the noise-plus-interference covariance, the maximum likelihood covariance estimation is mathematically derived. The simulation results verify that the proposed antenna combining with the structured covariance estimation provides a noticeable performance gain in the presence of TX leakage.