Effect of Antenna Beam Pattern and Layout on Cellular Performance in High Altitude Platform Communications

Abstract

High Altitude Platforms may offer high spectrum efficiency by deploying multi-beam, multi-cell communications networks. The properties of the antennas carried by the HAP payload are key to the effective exploitation of these benefits. This paper compares different models for the antenna sidelobe region and quantifies, in each case, the carrier to interference ratio for a 3 channel re-use plan. Networks of 121 and 313 cells are compared. We show how the ITU recommended pattern for the 47/48 GHz band leads to pessimistic results compared to an adapted pattern which fits that of measured data for an elliptic beam lens antenna. The method is then extended to consider other radiation patterns. Spectrum sharing issues are explored with reference to further ITU recommendations and comparison with measurement data. Finally, an ITU type cellular layout which uses the same antenna for each cell is compared to an alternative hexagonal layout where each cell has equal size.

High-Altitude Platforms Cellular System for Sparsely Populated Areas

“…In dealing with the footprint of HAPs, the cell parameters must be determined such as the major and minor axes and their variations with the utilized antenna beam widths and beam direction. In [7], the coverage of the HAP cell is well defined based on an assumption that the platform height is much smaller than the earth radius giving approximate figures for the cell dimensions especially at lower altitudes, while in [8], the HAP cell is determined by including the earth surface curvature and the cell parameters are determined with more complicated equations including the earth parameters itself. The HAP coverage area can extend to several hundreds of kilometers which is one of the main advantages of using it in cellular mobile communications and make it very feasible for covering largely and sparsely populated areas such as in the KSA and neighboring countries.…”

Handover Analysis for Yaw-Shifted High-Altitude Platforms

“…High-altitude platform (HAP) is a new promising technology for providing wireless mobile communications services [1][2][3][4][5][6][7][8]. It is efficient in many terms including system deployment, communications performance and infrastructure cost.…”

Flat-Top Ring-Shaped Cell Design for High-Altitude Platform Communications

“…The multi-beam horn (MBH) antenna and antenna arrays were developed for high-speed transmission at 48/47-GHz in [6], while in [7], a low sidelobe level and asymmetric beam antenna was developed using lens antenna to provide almost circular footprint especially at lower elevation angles. In [8], the concentric ring array (CRA) is examined to provide an improved HAP cellular coverage performance where it has many advantages such as independent azimuth beamforming and lower sidelobe levels.…”