Abstract
This paper proposes and evaluates the benefit of, one particular hybrid satellite-high-altitude-platform-station (HAPS)-ground network, where one HAPS connected to one geo-satellite assists the ground base stations (BSs) at serving ground-level users. The paper assumes that the geo-satellite is connected to the HAPS using free-space-optical backhaul links. The HAPS, equipped with multiple antennas, aims at transmitting the geo-satellite data to the users via radio-frequency (RF) links using spatial-multiplexing. Each ground BS, on the other hand, is equipped with multiple antennas, but directly serves the users through the RF links. The paper then focuses on maximizing the network-wide throughput, subject to HAPS payload connectivity constraint, HAPS and BSs power constraints, and backhaul constraints, so as to jointly determine the user-association strategy of each user (i.e., user to geo-satellite via HAPS, or user to BS), and their associated beamforming vectors. We tackle such a mixed discrete-continuous optimization problem using an iterative approach, where the user-association is determined using a combination of integer linear programming and generalized assignment problems, and where the beamforming strategy is found using a weighted-minimum-mean-squared-error approach. The simulations illustrate the appreciable gain of our proposed algorithm, and highlight the prospects of augmenting the ground networks with beamforming-empowered HAPS for connecting the unconnected, and super-connecting the connected.
Original language | English (US) |
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Pages (from-to) | 1-17 |
Number of pages | 17 |
Journal | IEEE Transactions on Vehicular Technology |
Volume | 73 |
Issue number | 4 |
DOIs | |
State | Accepted/In press - 2023 |
Bibliographical note
Publisher Copyright:IEEE
Keywords
- Array signal processing
- backhaul
- Backhaul networks
- beamforming
- High altitude platform station
- Interference
- Optimization
- Payloads
- Radio frequency
- satellite-HAPS-ground network
- Throughput
- throughput
- user association
ASJC Scopus subject areas
- Automotive Engineering
- Aerospace Engineering
- Computer Networks and Communications
- Electrical and Electronic Engineering