Uplink MIMO-SDMA optimisation of smart antennas by phase-amplitude perturbations based on memetic algorithms for wireless and mobile communication systems

Based on phase-amplitude perturbation method, an innovative uplink multiple-input multiple-output spatial division multiple access (MIMO-SDMA) optimisation technique of smart antennas is proposed, where the deduced radiation pattern formulas available for searching optimal solutions are used to search the optimal weighting vector of the array factor of a smart antenna. The design for an optimal radiation pattern of an adaptive antenna can not only adjustably suppress interferers by placing nulls at the directions of the interfering sources but also provide a maximum main lobe in the direction of the desired signal at the same time, that is to maximise the signal to interference ratio. A new convergent method referred as the two-way convergent method for memetic algorithms is proposed to achieve this goal. A smart antenna is composed by several adaptive antennas. The smart antenna is implemented via using the adaptive beamforming technique. The characteristic is that the optimal radiation pattern design of smart antennas is studied by using phase-amplitude perturbation method to achieve MIMO-SDMA optimisation