Ph.D., Lic. Theses
Many new wireless comunication standards use complex modulation schemes with many subcarriers; which put high requirements on small Quadrature Errors. Linearization schemes such as digital predistortion also put high requirements on Quadrature Errors and in-band filter response.
This paper describes the development of an adaptive signal processing algorithm aiming to correct frequency dependent Quadrature Errors and to improve the in-band frequency response simultaneously. The correction is done in frequency domain using 4-by-4 matrix multiplication with different coefficients for different subcarrier group
Theory and simulation suggest that these algorithms substantially can improve the transceiver performance and/or relax the requirements on its analogue and mixed signal components.
