In this paper we present a digital beamforming scheme for wireless communication systems based on high altitude platforms. The proposed digital beamforming scheme, which is installed on the platforms in high-altitude-platform (HAP) systems, can reduce significantly the number of antenna elements and the corresponding receiver modules, analog to digital (A/D) converters etc. without loss of performance. As a result, the system complexity and the system costs can be reduced, therefore enhancing feasibility of HAP-based systems. Moreover, in the proposed scheme, it allows to specify narrow main beam width and low sidelobe level simultaneously. An illustrative example, which demonstrates the design of the new method, is included     «

In this paper we present a digital beamforming scheme for wireless communication systems based on high altitude platforms. The proposed digital beamforming scheme, which is installed on the platforms in high-altitude-platform (HAP) systems, can reduce significantly the number of antenna elements and the corresponding receiver modules, analog to digital (A/D) converters etc. without loss of performance. As a result, the system complexity and the system costs can be reduced, therefore enhancing fe...     »