Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes
Satellites in low earth orbit (LEO) are currently being deployed for numerous communication, positioning, space and Earth-imaging missions. To provide higher data rates in direct-to-user links and earth observation downlinks, the free-space optics technology can be employed for LEO-to-ground downlin...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Photonics |
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| Online Access: | https://www.mdpi.com/2304-6732/9/2/92 |
| _version_ | 1797477142730113024 |
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| author | Theodore T. Kapsis Athanasios D. Panagopoulos |
| author_facet | Theodore T. Kapsis Athanasios D. Panagopoulos |
| author_sort | Theodore T. Kapsis |
| collection | DOAJ |
| description | Satellites in low earth orbit (LEO) are currently being deployed for numerous communication, positioning, space and Earth-imaging missions. To provide higher data rates in direct-to-user links and earth observation downlinks, the free-space optics technology can be employed for LEO-to-ground downlinks. Moreover, the hybrid automatic repeat request (HARQ) can be adopted since the propagation latency is low for LEO satellites. In this work, a power allocation methodology is proposed for optical LEO-to-ground downlinks under weak turbulence employing HARQ retransmission schemes. Specifically, the average power consumption is minimized given a maximum transmitted power constraint and a target outage probability threshold to ensure energy efficiency and reliability, respectively. The optimization problem is formulated as a constrained nonlinear programming problem and solved for Type I HARQ, chase combining (CC) and incremental redundancy (IR) schemes. The solutions are derived numerically via iterative algorithms, namely interior-point (IP) and sequential quadratic programming (SQP), and validated through an exhaustive (brute-force) search. The numerical simulations provide insight into the performance of the retransmission schemes regarding average power. More specifically, Type I HARQ has the worst output, CC has a moderate one, and IR exhibits the best performance. Finally, the IP algorithm is a slower but more accurate solver, and SQP is faster but slightly less accurate. |
| first_indexed | 2024-03-09T21:13:26Z |
| format | Article |
| id | doaj.art-d20f1a1413a54b44b4da88cdd4dbb15e |
| institution | Directory Open Access Journal |
| issn | 2304-6732 |
| language | English |
| last_indexed | 2024-03-09T21:13:26Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Photonics |
| spelling | doaj.art-d20f1a1413a54b44b4da88cdd4dbb15e2023-11-23T21:41:21ZengMDPI AGPhotonics2304-67322022-02-01929210.3390/photonics9020092Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ SchemesTheodore T. Kapsis0Athanasios D. Panagopoulos1School of Electrical and Computer Engineering, National Technical University of Athens, GR-15780 Athens, GreeceSchool of Electrical and Computer Engineering, National Technical University of Athens, GR-15780 Athens, GreeceSatellites in low earth orbit (LEO) are currently being deployed for numerous communication, positioning, space and Earth-imaging missions. To provide higher data rates in direct-to-user links and earth observation downlinks, the free-space optics technology can be employed for LEO-to-ground downlinks. Moreover, the hybrid automatic repeat request (HARQ) can be adopted since the propagation latency is low for LEO satellites. In this work, a power allocation methodology is proposed for optical LEO-to-ground downlinks under weak turbulence employing HARQ retransmission schemes. Specifically, the average power consumption is minimized given a maximum transmitted power constraint and a target outage probability threshold to ensure energy efficiency and reliability, respectively. The optimization problem is formulated as a constrained nonlinear programming problem and solved for Type I HARQ, chase combining (CC) and incremental redundancy (IR) schemes. The solutions are derived numerically via iterative algorithms, namely interior-point (IP) and sequential quadratic programming (SQP), and validated through an exhaustive (brute-force) search. The numerical simulations provide insight into the performance of the retransmission schemes regarding average power. More specifically, Type I HARQ has the worst output, CC has a moderate one, and IR exhibits the best performance. Finally, the IP algorithm is a slower but more accurate solver, and SQP is faster but slightly less accurate.https://www.mdpi.com/2304-6732/9/2/92free-space opticslow earth orbit satellitepower allocationhybrid automatic repeat requestweak turbulencechase combining |
| spellingShingle | Theodore T. Kapsis Athanasios D. Panagopoulos Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes Photonics free-space optics low earth orbit satellite power allocation hybrid automatic repeat request weak turbulence chase combining |
| title | Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes |
| title_full | Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes |
| title_fullStr | Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes |
| title_full_unstemmed | Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes |
| title_short | Power Allocation for Reliable and Energy-Efficient Optical LEO-to-Ground Downlinks with Hybrid ARQ Schemes |
| title_sort | power allocation for reliable and energy efficient optical leo to ground downlinks with hybrid arq schemes |
| topic | free-space optics low earth orbit satellite power allocation hybrid automatic repeat request weak turbulence chase combining |
| url | https://www.mdpi.com/2304-6732/9/2/92 |
| work_keys_str_mv | AT theodoretkapsis powerallocationforreliableandenergyefficientopticalleotogrounddownlinkswithhybridarqschemes AT athanasiosdpanagopoulos powerallocationforreliableandenergyefficientopticalleotogrounddownlinkswithhybridarqschemes |