Geometrical Correction for Cell Deployment in Stratospheric Cellular Systems

Abstract

Abstract-In this paper, cellular communications from Stratospheric platforms (SPs) is studied, and the coverage footprint analysis and design is demonstrated. In the analysis, two coverage schemes are introduced; flat-earth and real-earth models and cell footprint are determined in each case. The flat-earth provides simple footprint equations describing the cell dimensions especially for the cells of higher elevation angles while more accurate coverage equations, which well determine the geometry of the cells of lower elevation angles, can be obtained from the real-earth scheme. The design of a cellular system using the proposed coverage models is then introduced through a procedure that determines the cells locations and dimensions on the ground according to the teletraffic information. The procedure takes into considerations the cell broadening when going outwardly from the central cell to the outer lower elevation cells and constructs a cellular layout that has the most proper cells overlap and uniform coverage edges, which helps the linking between different SPs coverage areas.

Handover Analysis for Yaw-Shifted High-Altitude Platforms

“…and in this case the value of c  will be (13) Therefore the cell minor axis, C a , will be (15) which can be also given by…”

“…9, where a fixed spot beam antennas of beamwidth 10 degrees are used to layout 127 cells covering a whole area of radius 30 km approximately and the HAP height is 20 km. The distance between the neighboring cells is calculated as in [15] where the coverage overlap between cells is optimized. One notice for this cellular structure is that the cells will be flattened when going outward due to the beam projection at lower elevation angles and this is acceptable because the user density also is always decreasing at the cell edges rather than at the center.…”

A Novel Location Determination Technique for Traffic Control and Surveillance using Stratospheric Platforms

“…2 where the array is UCA of N elements equally separated by half of wavelength distance. For the circular array, the output signal is given by: (7) where is the transpose of the circular array weights vector and is the array received signal vector given by: (8) or (9) where are the steering vectors of the circular array corresponding to the received signals, each of size , is the array steering matrix and equals: with a size of . The circular array steering vector at any direction is given by [24]: (10) Where the interelement separation is taken as half of the wavelength.…”

“…Recently, an innovated communications system based on utilizing high altitude stratospheric platforms has a great interest especially for mobile and wireless data communications. The platforms are known under different names as High-Altitude Platforms (HAPs), High Altitude Aircraft and Airships (HAAS), High Altitude Aeronautical Platforms (HAAPs), High Altitude Long Endurance Platforms (HALE Platforms), Stratospheric Platforms (SPs), etc [2][3][4][5][6][7][8][9][10][11]. They are located at 17-22 km above the earth surface and ITU has allocated specifically for HAPs services the spectrum of 600 MHz at 47/48 GHz (shared with satellites) worldwide.…”

Performance of High-Altitude Platforms Cellular Communications using Hamming-Tapered Concentric Circular Arrays

“…These two factors can be integrated into one term denoted by the power profile function (or the received signal power gain) which can be deduced by considering the received signal power by a mobile from HAP. Assuming free-space propagation scenario between the HAP and mobile users, therefore we can write an expression for the received signal power r P from a HAP by a mobile as: (15) where t P is the transmitted HAP beam power, …”