A Novel Design of Arbitrary Shaped Cells for Efficient Coverage from High Altitude Platforms (original) (raw)
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A Novel Beamforming Technique for Highways Coverage Using High-Altitude Platforms
2007
This paper proposes a novel beamforming technique to form an arbitrary-shaped cell for the high-altitude platforms (HAPs) mobile communications. The new technique is based on pattern summation of individual low-sidelobe, narrow beams which constitute the desired cell pattern weighted by an amplitude correcting function. The new cell pattern can be adapted to cover the main highways forming worm-shaped cells which may cover the highway for long distances up to 100 km and it will have an important role in reducing frequent handoffs and signaling traffic of location updating from moving users over the long highways.
ResearchLetter A Novel Beamforming Technique for Highways Coverage Using High-Altitude Platforms
2000
This paper proposes a novel beamforming technique to form an arbitrary-shaped cell for the high-altitude platforms (HAPs) mobile communications. The new technique is based on pattern summation of individual low-sidelobe, narrow beams which constitute the desired cell pattern weighted by an amplitude correcting function. The new cell pattern can be adapted to cover the main highways forming worm-shaped cells which may cover the highway for long distances up to 100 km and it will have an important role in reducing frequent handoffs and signaling traffic of location updating from moving users over the long highways.
A Novel Wormy Cellular Structure for High Altitude Platforms Mobile Communications
Wireless Personal Communications, 2008
In this paper, a novel beamforming technique is proposed for the high altitude platforms (HAPs) mobile communications to generate adaptive radio coverage worm-shaped cells to cover the main highways. This technique is based on pattern summation of individual low-sidelobe narrow beams-which constitute the desired cell pattern-weighted by an adaptive amplitude correcting function. The new shaped cell differs from the conventional hexagonal or elliptical cells as it follows the curvatures of the highway for long distances up to 100 km, therefore it has an important role in reducing the frequent handoff and signaling traffic of location updating from moving users over long highways.
Wireless Personal Communications, 2005
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.
Optimization of Beams Directions for High Altitude Platforms Cellular Communications Design
2006
Cellular communications using high altitude platforms will predominate the existing conventional terrestrial or satellite cellular systems but requires some optimization especially in the, radio coverage cellular design. In this paper either spot-beam antennas or antenna phased arrays are used in the radio coverage which is optimized in directing their beams to satisfy mostly uniform cellular layout with minimal coverage problems such as coverage gaps between cells or excessive cells overlap
High-Altitude Platforms Cellular System for Sparsely Populated Areas
International Journal of Computer Network and Information Security, 2014
In this paper, the cellular communications using high altitude platform (HAP) will be discussed including the coverage analysis and design. The cells are analyzed showing the main parameters affecting its shape, layout and area which are important in the cellular design stage. This HAP cellular system is very important to cross the gap of difficult extension of ground infrastructure especially for sparsely populated areas needing communications services. The system design is explained where the footprint of the HAP cell is demonstrated and the overall cellular layout is established. As a case study, the coverage of the HAP cellular system is proved to cover some areas in the Kingdom of Saudi Arabia (KSA) using several scenarios such as populated as well as long highways passing through desert areas. The HAP cells are generated using spot-beam antennas which are practically candidate. The simulation results show that a single HAP can provide hundreds of microcells for urban areas while covering very long highways that can extend to several hundreds of kilometers which is very useful in covering the long highways linking sparsely separated cities in KSA.
Optimizing an array of antennas for cellular coverage from a high altitude platform
IEEE Transactions on Wireless Communications, 2003
In a wireless communications network served by a high altitude platform (HAP) the cochannel interference is a function of the antenna beamwidth, angular separation and sidelobe level. At the millimeter wave frequencies proposed for HAPs, an array of aperture type antennas on the platform is a practicable solution for serving the cells. We present a method for predicting cochannel interference based on curve-fit approximations for radiation patterns of elliptic beams which illuminate cell edges with optimum power, and a means of estimating optimum beamwidths for each cell of a regular hexagonal layout. The method is then applied to a 121 cell architecture. Where sidelobes are modeled as a flat floor at 40-dB below peak directivity, a cell cluster size of four yields carrier-to-interference ratios (CIRs), which vary from 15 dB at cell edges to 27 dB at cell centers. On adopting a cluster size of seven, these figures increase, respectively, to 19 and 30 dB. On reducing the sidelobe level, the improvement in CIR can be quantified. The method also readily allows for regions of overlapping channel coverage to be shown.
International Journal of Computer Applications, 2014
In this paper, the concentric ring shaped cellular configuration is designed for High Altitude Platforms (HAPs). An one dimensional (1D) vertical linear antenna array is used to generate this configuration. The effect of different types of HAP mobility models, e.g. drift, random walk, and reflection has been examined. The possibility of reducing the need for mechanical stabilization via handoff techniques is demonstrated through the study of handoff, dropping, and blocking probabilities.
Flat-Top Ring-Shaped Cell Design for High-Altitude Platform Communications
2013
In this paper, a new design for ring-shaped cells is introduced where to improve the power distribution and carrier-to-interference ratio (CIR) over the cell area. The designed cell has flat-top radiation pattern with minimal ripples in the service area while the out-of-cell area has lower radiation levels. The new design utilizes two weighting functions applied to a vertical linear array; the first is responsible for the flat-top design and the second smoothes the pattern and reduces the sidelobe levels. The resulted power pattern has a uniform distribution over the cell stripe with as small as 0.25 dB ripples and a uniform CIR values greater than 43 dB within the cells which reduces the burden of power control and increases the immunity to propagation problems.
International Journal of Information Technology and Computer Science, 2014
In this paper, the performance of cellular communications based on the ambitious technology of High-Altitude Platforms (HAPs) is discussed when using tapered concentric circular arrays. The coverage cell will be described and designed with an efficient beamforming technique where the Hamming window is proposed as a tapering function and applied to the uniform concentric circular arrays (UCCA) for sidelobe reduction. Based on establishing some mapping curves, this novel tapering window is optimized in its parameters to have the lowest possible sidelobe level that can be 45 dB below the main lobe level. The optimum weights of Hamming window are found to be function of the number of elements of the innermost ring and the number of rings in the array. The cell power pattern is also discussed where the out-of-cell radiation is greatly reduced which in turns reduces the co-channel interference and improves the Carrier-to-Interference Ratio (CIR).