# Inter-Satellite Cooperative Offloading Decision and Resource Allocation in Mobile Edge Computing-Enabled Satellite–Terrestrial Networks

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## Abstract

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## 1. Introduction

- The system model of the MEC-enabled STN is established to provide MEC services in remote or disaster areas by utilizing inter-satellite cooperation. The joint task offloading and computing resource allocation problem is formulated to minimize the task completion delay and decomposed into a task offloading decision problem and a computing resource allocation problem.
- An inter-satellite cooperative joint offloading decision and resource allocation optimization scheme, which consists of a task offloading decision algorithm based on the Grey Wolf Optimizer (GWO) algorithm and a computing resource allocation algorithm based on the Lagrange multiplier method is proposed. The optimal task offloading decision and computing resource allocation are obtained by the proposed scheme.
- The performance of the proposed scheme is evaluated by comparing it with other baseline schemes with respect to the variation of some parameters. Simulation results demonstrate the performance gain of the proposed scheme.

## 2. Related Work

## 3. System Model

#### 3.1. Network Model

#### 3.2. Channel Model

#### 3.3. Computation Model

## 4. Problem Formulation

## 5. Algorithm Design

Algorithm 1 GWOORAC |

1: Initialize the grey wolf population, $\overrightarrow{a}$, $\overrightarrow{A}$, and $\overrightarrow{C}$. Set $t=1$. Set ${t}^{\mathrm{max}}$. |

3: while$1\le t\le {t}^{\mathrm{max}}$do |

4: for each $l\in {\mathcal{N}}^{\omega}$ do |

5: Update ${\overrightarrow{X}}_{l}$. |

6: Update $\overrightarrow{a}$, $\overrightarrow{A}$, and $\overrightarrow{C}$. |

8: if ${U}_{l}<{U}_{\alpha}$ then |

9: update ${\overrightarrow{X}}_{\alpha}={\overrightarrow{X}}_{l}$, ${U}_{\alpha}={U}_{l}$. |

10: else if ${U}_{l}>{U}_{\alpha}$ and ${U}_{l}<{U}_{\beta}$ then |

11: update ${\overrightarrow{X}}_{\beta}={\overrightarrow{X}}_{l}$, ${U}_{\beta}={U}_{l}$. |

12: else if ${U}_{l}>{U}_{\alpha}$ and ${U}_{l}>{U}_{\beta}$ and ${U}_{l}<{U}_{\delta}$ then |

13: update ${\overrightarrow{X}}_{\delta}={\overrightarrow{X}}_{l}$, ${U}_{\delta}={U}_{l}$. |

14: end if |

15: end for |

16: $t=t+1$. |

17: end while |

18: return${\overrightarrow{X}}_{\alpha}$ and ${U}_{\alpha}$. |

## 6. Simulation and Analysis

#### 6.1. Simulation Parameters

#### 6.2. Simulation Results and Analysis

## 7. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- IMT-2030 6G Promotion Group. The 6G Overall Vision and Potential Key Technologies White Paper, 1st ed.; IMT-2030 6G Promotion Group: Beijing, China, 2021; pp. 1–32. (In Chinese) [Google Scholar]
- Chen, S.; Sun, S.; Kang, S. System Integration of Terrestrial Mobile Communication and Satellite Communication-The Trends, Challenges and Key Technologies in B5G and 6G. China Commun.
**2020**, 17, 156–171. [Google Scholar] [CrossRef] - Tirmizi, S.B.R.; Chen, Y.; Lakshminarayana, S.; Feng, W.; Khuwaja, A.A. Hybrid Satellite–Terrestrial Networks toward 6G: Key Technologies and Open Issues. Sensors
**2022**, 22, 8544. [Google Scholar] [CrossRef] [PubMed] - Zhang, F.; Wang, M.M. Stochastic Congestion Game for Load Balancing in Mobile-Edge Computing. IEEE Internet Things J.
**2021**, 8, 778–790. [Google Scholar] [CrossRef] - Zhao, T.; Zhou, S.; Song, L.; Jiang, Z.; Guo, X.; Niu, Z. Energy-Optimal and Delay-Bounded Computation Offloading in Mobile Edge Computing with Heterogeneous Clouds. China Commun.
**2020**, 17, 191–210. [Google Scholar] [CrossRef] - Patel, M.; Naughton, B.; Chan, C.; Sprecher, N.; Abeta, S.; Neal, A. Mobile-Edge Computing-Introductory Technical White Paper, 1st ed.; ETSI: Sophia Antipolis, France, 2014; pp. 1–36. [Google Scholar]
- Liu, X.; Zhao, X.; Liu, G.; Huang, F.; Huang, T.; Wu, Y. Collaborative Task Offloading and Service Caching Strategy for Mobile Edge Computing. Sensors
**2022**, 22, 6760. [Google Scholar] [CrossRef] [PubMed] - Liu, J.; Zhang, Q. Code-Partitioning Offloading Schemes in Mobile Edge Computing for Augmented Reality. IEEE Access
**2019**, 7, 11222–11236. [Google Scholar] [CrossRef] - Huang, S.; Zhang, J.; Wu, Y. Altitude Optimization and Task Allocation of UAV-Assisted MEC Communication System. Sensors
**2022**, 22, 8061. [Google Scholar] [CrossRef] - Zou, C.; Wang, H.; Chang, J.; Shao, F.; Shang, L.; Li, G. Optimal Progressive Pitch for OneWeb Constellation with Seamless Coverage. Sensors
**2022**, 22, 6302. [Google Scholar] [CrossRef] - Jin, L.; Wang, L.; Jin, X.; Zhu, J.; Duan, K.; Li, Z. Research on the Application of LEO Satellite in IOT. In Proceedings of the 2022 IEEE 2nd International Conference on Electronic Technology, Communication and Information (ICETCI), Changchun, China, 27–29 May 2022; pp. 739–741. [Google Scholar] [CrossRef]
- Xie, R.; Tang, Q.; Wang, Q.; Liu, X.; Richard Yu, F.; Huang, T. Satellite-Terrestrial Integrated Edge Computing Networks: Architecture, Challenges, and Open Issues. IEEE Netw.
**2020**, 34, 224–231. [Google Scholar] [CrossRef] - Xiao, Z.; Dai, X.; Jiang, H.; Wang, D.; Chen, H.; Yang, L.; Zeng, F. Vehicular Task Offloading via Heat-Aware MEC Cooperation Using Game-Theoretic Method. IEEE Internet Things J.
**2020**, 7, 2038–2052. [Google Scholar] [CrossRef] - Yang, Z.; Liu, H.; Jin, J.; Tian, F. A Cooperative Routing Scheme Using Inter-Satellite Links to Assist Data Downloading for LEO Satellite Networks. Sensors
**2022**, 22, 7986. [Google Scholar] [CrossRef] [PubMed] - Liu, S.; Guo, X.; Lai, J.; Yang, J. Distributed Timekeeping in BeiDou Inter-satellite Link Network. IEEE Commun. Lett. 2022, in press. [CrossRef]
- Li, S.; Sun, W.; Sun, Y.; Huo, Y. Energy-Efficient Task Offloading Using Dynamic Voltage Scaling in Mobile Edge Computing. IEEE Trans. Netw. Sci. Eng.
**2021**, 8, 588–598. [Google Scholar] [CrossRef] - Zhang, G.; Zhang, S.; Zhang, W.; Shen, Z.; Wang, L. Joint Service Caching, Computation Offloading and Resource Allocation in Mobile Edge Computing Systems. IEEE Trans. Wirel. Commun.
**2021**, 20, 5288–5300. [Google Scholar] [CrossRef] - Zhu, X.; Jiang, C. Integrated Satellite-Terrestrial Networks Toward 6G: Architectures, Applications, and Challenges. IEEE Internet Things J.
**2022**, 9, 437–461. [Google Scholar] [CrossRef] - Zhang, Z.; Zhang, W.; Tseng, F.H. Satellite Mobile Edge Computing: Improving QoS of High-Speed Satellite-Terrestrial Networks Using Edge Computing Techniques. IEEE Netw.
**2019**, 33, 70–76. [Google Scholar] [CrossRef] - Al Homssi, B.; Al-Hourani, A.; Wang, K.; Conder, P.; Kandeepan, S.; Choi, J.; Allen, B.; Moores, B. Next Generation Mega Satellite Networks for Access Equality: Opportunities, Challenges, and Performance. IEEE Commun. Mag.
**2022**, 60, 18–24. [Google Scholar] [CrossRef] - Cao, X.; Li, Y.; Xiong, X.; Wang, J. Dynamic Routings in Satellite Networks: An Overview. Sensors
**2022**, 22, 4552. [Google Scholar] [CrossRef] - Pi, J.; Ran, Y.; Wang, H.; Zhao, Y.; Zhao, R.; Luo, J. Dynamic Planning of Inter-Plane Inter-Satellite Links in LEO Satellite Networks. In Proceedings of the ICC 2022—IEEE International Conference on Communications, Seoul, Republic of Korea, 16–20 May 2022; pp. 3070–3075. [Google Scholar] [CrossRef]
- Wang, H.; Han, J.; Cao, S.; Zhang, X. Computation Offloading Strategy of Multi-satellite Cooperative Tasks Based on Genetic Algorithm in Satellite Edge Computing. In Proceedings of the 2021 International Conference on Space-Air-Ground Computing (SAGC), Huizhou, China, 23–25 October 2021; pp. 22–28. [Google Scholar] [CrossRef]
- Wang, Y.; Zhang, J.; Zhang, X.; Wang, P.; Liu, L. A Computation Offloading Strategy in Satellite Terrestrial Networks with Double Edge Computing. In Proceedings of the 16th IEEE International Conference on Communication Systems (IEEE ICCS), Chengdu, China, 19–21 December 2018; pp. 450–455. [Google Scholar] [CrossRef]
- Zhang, J.; Zhang, X.; Wang, P.; Liu, L.; Wang, Y. Double-Edge Intelligent Integrated Satellite Terrestrial Networks. China Commun.
**2020**, 17, 128–146. [Google Scholar] [CrossRef] - Tang, Q.; Fei, Z.; Li, B.; Han, Z. Computation Offloading in LEO Satellite Networks With Hybrid Cloud and Edge Computing. IEEE Internet Things J.
**2021**, 8, 9164–9176. [Google Scholar] [CrossRef] - Song, Z.; Hao, Y.; Liu, Y.; Sun, X. Energy-Efficient Multiaccess Edge Computing for Terrestrial-Satellite Internet of Things. IEEE Internet Things J.
**2021**, 8, 14202–14218. [Google Scholar] [CrossRef] - Abu-Taleb, N.A.; Hasan Abdulrazzak, F.; Zahary, A.T.; Al-Mqdashi, A.M. Offloading Decision Making in Mobile Edge Computing: A Survey. In Proceedings of the 2022 2nd International Conference on Emerging Smart Technologies and Applications (eSmarTA), Ibb, Yemen, 25–26 October 2022; pp. 1–8. [Google Scholar] [CrossRef]
- Luo, Q.; Hu, S.; Li, C.; Li, G.; Shi, W. Resource Scheduling in Edge Computing: A Survey. IEEE Commun. Surv. Tutorials
**2021**, 23, 2131–2165. [Google Scholar] [CrossRef] - Deng, R.; Di, B.; Zhang, H.; Kuang, L.; Song, L. Ultra-Dense LEO Satellite Constellations: How Many LEO Satellites Do We Need? IEEE Trans. Wirel. Commun.
**2021**, 20, 4843–4857. [Google Scholar] [CrossRef] - Lee, Y.; Choi, J.P. Connectivity Analysis of Mega-Constellation Satellite Networks with Optical Intersatellite Links. IEEE Trans. Aerosp. Electron. Syst.
**2021**, 57, 4213–4226. [Google Scholar] [CrossRef] - Ekici, E.; Akyildiz, I.F.; Bender, M.D. A distributed routing algorithm for datagram traffic in LEO satellite networks. IEEE ACM Trans. Netw.
**2001**, 9, 137–147. [Google Scholar] [CrossRef] - Tang, L.; Hu, H. Computation Offloading and Resource Allocation for the Internet of Things in Energy-Constrained MEC-Enabled HetNets. IEEE Access
**2020**, 8, 47509–47521. [Google Scholar] [CrossRef] - Hou, Y.; Gao, H.; Wang, Z.; Du, C. Improved Grey Wolf Optimization Algorithm and Application. Sensors
**2022**, 22, 3810. [Google Scholar] [CrossRef] - Mirjalili, S.; Mirjalili, S.M.; Lewis, A. Grey Wolf Optimizer. Adv. Eng. Softw.
**2014**, 69, 46–61. [Google Scholar] [CrossRef] [Green Version]

Parameter | Value | Parameter | Value |
---|---|---|---|

N | 50 | M | 5 |

${c}_{i}$ | 1000 cycles/bit | ${a}_{i}$ | [0.5, 5] Mbits |

${f}_{i,0}$ | [1, 2] Gcycles/s | ${p}_{i}$ | 2 W |

${g}_{i}$ | 43.3 dBi | ${B}_{i,1}$ | 100 MHz |

${B}_{1,j}$ | 100 MHz | P | 50 W |

${F}_{1}$ | 12 Gcycles/s | ${F}_{j}$ | 12 Gcycles/s |

${D}_{\mathrm{TA}}$ | 2.2 m | ${N}_{{0}_{i,1}}$ | −203 dBm/Hz |

${N}_{{0}_{1,j}}$ | −203 dBm/Hz | ${R}_{\mathrm{e}}$ | 6371 km |

${\theta}_{min}^{\mathrm{U}}$ | ${16}^{\circ}$ | $lat$ | ${60}^{\circ}$ |

${h}_{\mathrm{s}}$ | 780 km | c | $3\times {10}^{8}$ m/s |

f | 30 GHz | K | 7 |

I | 6 | J | 11 |

${N}^{\mathrm{W}}$ | 20 | ${t}^{\mathrm{max}}$ | 200 |

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**MDPI and ACS Style**

Tong, M.; Li, S.; Wang, X.; Wei, P.
Inter-Satellite Cooperative Offloading Decision and Resource Allocation in Mobile Edge Computing-Enabled Satellite–Terrestrial Networks. *Sensors* **2023**, *23*, 668.
https://doi.org/10.3390/s23020668

**AMA Style**

Tong M, Li S, Wang X, Wei P.
Inter-Satellite Cooperative Offloading Decision and Resource Allocation in Mobile Edge Computing-Enabled Satellite–Terrestrial Networks. *Sensors*. 2023; 23(2):668.
https://doi.org/10.3390/s23020668

**Chicago/Turabian Style**

Tong, Minglei, Song Li, Xiaoxiang Wang, and Peng Wei.
2023. "Inter-Satellite Cooperative Offloading Decision and Resource Allocation in Mobile Edge Computing-Enabled Satellite–Terrestrial Networks" *Sensors* 23, no. 2: 668.
https://doi.org/10.3390/s23020668