Optimal Beamwidth for Maximizing Uplink Coverage Probability in Quasi Earth-Fixed LEO Satellite Communication System
Abstract
:1. Introduction
- Quasi earth-fixed cells (QEFC): satellites can compensate and steer the beams at the same position on the earth while satellites move.
- Earth-moving cells (EMC): satellites cannot provide steerable beams. The position of beams changes while satellites move.
2. System Model
3. Optimal Beamwidth Maximizing Uplink Coverage Probability Scheme
3.1. Beam Boresight Direction
3.2. Uplink Coverage Probability Analysis Model
3.3. Beamwidth Optimization
Algorithm 1 Optimal Beamwidth Maximizing Uplink Coverage Probability Scheme |
Input: Beam position on Earth , satellite hight h, and time t Output: Beam boresight direction , , and optimal equivalent antenna aperture
|
4. Numerical Results and Discussion
- 3GPP setting: the equivalent antenna aperture is 2 m, the max receive antenna gain is 30 dBi, and the half-power beamwidth is [18].
- 3GPP setting with three-color frequency reuse (FRF3): The frequency band is divided into three sub-bands, and the adjacent beams are allocated to different sub-bands. Other assumptions follow the 3GPP setting. The three-color frequency reuse is also known as frequency reuse factor three.
- Exhaustive antenna aperture search: exhaustively search the equivalent antenna aperture with the highest uplink coverage probability in a predefined target SINR for each simulated time. The exhaustive antenna aperture search denotes the upper bound of the uplink coverage probability for non-frequency reuse.
4.1. Signal Quality
4.2. Uplink Coverage Probability
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Abbreviations
3GPP | Third-Generation Partnership Project |
5G | Fifth-Generation mobile network |
ECEF | Earth-Centered Earth-Fixed |
EMC | Earth-moving cells |
FRF3 | Three-color frequency reuse |
FSPL | Free-space path loss |
LEO | Low earth orbit |
LOS | Line-of-sight |
NLOS | Non-line-of-sight |
NR | New Radio |
NTN | Non-terrestrial networks |
PUSCH | Physical uplink shared channel |
QEFC | Quasi earth-fixed cells |
SINR | Signal-to-interference-plus-noise ratio |
UE | User equipment |
VoNR | Voice-over New Radio |
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Notation | Distriptions |
---|---|
The set of the simulated frequency band and time. for FRF3 and for non-frequency reuse. | |
The set of beams in frequency band f (), UE serving by beam l (). | |
Elevation angle of beam l, elevation angle of user s served by beam l. | |
Clutter loss. Clutter loss is 0 for the LOS state. The values for the (NLOS state at elevation angle are defined in [16]. | |
Shadow fading at elevation angle . Shadow fading is zero mean Gaussian variable. | |
The variation in shadow fading for lien-of-sight (LOS) and non line-of-sight (NLOS) states at elevation angle [16]. | |
LOS probability and NLOS probability at elevation angle [16]. | |
Angle difference of boresight direction between beam l and beam k ( and ). | |
Angle difference of UE s and boresight direction of beam l. | |
The probability of the condition x to be satisfied, . |
Assumption | Value |
---|---|
Satellite height | 600 km |
Satellite beam pattern | 19 spot beams with wrap-around |
Max antenna gain for 3GPP setting and FRF3 | 30 dBi |
Carrier frequency | 2 GHz |
UE-type | Handheld |
UE antenna configuration | Omni-directional, −5.5 dBi antenna gain [19] |
UE transmit power | 23 dBm |
UE attachment | RSRP |
Scheduled bandwidth | 180 kHz (1 resource block) |
Noise power | −147 dBW |
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Liu, C.-T.; Pan, J.-Y. Optimal Beamwidth for Maximizing Uplink Coverage Probability in Quasi Earth-Fixed LEO Satellite Communication System. Electronics 2024, 13, 1349. https://doi.org/10.3390/electronics13071349
Liu C-T, Pan J-Y. Optimal Beamwidth for Maximizing Uplink Coverage Probability in Quasi Earth-Fixed LEO Satellite Communication System. Electronics. 2024; 13(7):1349. https://doi.org/10.3390/electronics13071349
Chicago/Turabian StyleLiu, Chun-Tai, and Jen-Yi Pan. 2024. "Optimal Beamwidth for Maximizing Uplink Coverage Probability in Quasi Earth-Fixed LEO Satellite Communication System" Electronics 13, no. 7: 1349. https://doi.org/10.3390/electronics13071349
APA StyleLiu, C.-T., & Pan, J.-Y. (2024). Optimal Beamwidth for Maximizing Uplink Coverage Probability in Quasi Earth-Fixed LEO Satellite Communication System. Electronics, 13(7), 1349. https://doi.org/10.3390/electronics13071349