Singular value decomposition based adaptive transmission scheme for misalignment cross polarized MIMO system

In the conventional multi-input multi-output (MIMO) communication systems, only spatially separated uni-polarized antenna elements are mainly considered in a lot of research works, and some researcher consider to use the cross-polarized MIMO system to reduce the channel correlation effect in MIMO channel matrix. By using orthogonal polarized antennas in the MIMO system, the transmitted signal from vertical and horizontal polarized antennas are easily separated in MIMO receiver. However, misalignment between transmitter and receiver sides might be occurred because of rotation of transmit or receive antennas in the system. In this situation cross-polarized discrimination (XPD) ability is no longer reliable in this kind of MIMO system and we proposed the adaptive transmission scheme to improve the bit error rate (BER) performance for misalignment cross-polarized MIMO system. In the proposed scheme, transmission methods are adaptively changed based on the calculation of singular value decomposition (SVD) of channel matrix. Simulation results show that BER performance can be improved under the constraint of target data rate and total transmit power of the MIMO system.