Smart antenna technology for high-altitude-platform based wireless communication systems

In this paper we present a digital beamforming scheme for future 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 system costs can be reduced, therefore, enhancing feasibility of HAP based systems. Furthermore, in the proposed scheme, we can specify narrow main beamwidth and low sidelobe level simultaneously. Illustrative design examples and beam-pattern comparisons with traditional digital beamforming methods are included.