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Beam Management in Low Earth Orbit Satellite Communication With Handover Frequency Control and Satellite-Terrestrial Spectrum Sharing

Yaohua Sun, Jianfeng Zhu, Mugen Peng

TL;DR

This paper forms a practical beam management problem, aiming to maximize the long-term service satisfaction of cells, and decomposes it into three subproblems, including inter-satellite handover decision, beam hopping design and satellite-terrestrial spectrum sharing.

Abstract

To achieve ubiquitous wireless connectivity, low earth orbit (LEO) satellite networks have drawn much attention. However, effective beam management is challenging due to time-varying cell load, high dynamic network topology, and complex interference situations. In this paper, under inter-satellite handover frequency and satellite-terrestrial/inter-beam interference constraints, we formulate a practical beam management problem, aiming to maximize the long-term service satisfaction of cells. Particularly, Lyapunov framework is leveraged to equivalently transform the primal problem into multiple single epoch optimization problems, where virtual queue stability constraints replace inter-satellite handover frequency constraints. Since each single epoch problem is NP-hard, we further decompose it into three subproblems, including inter-satellite handover decision, beam hopping design and satellite-terrestrial spectrum sharing. First, a proactive inter-satellite handover mechanism is developed to balance handover frequency and satellite loads. Subsequently, a beam hopping design algorithm is presented based on conflict graphs to achieve interference mitigation among beams, and then a flexible satellite-terrestrial spectrum sharing algorithm is designed to satisfy the demands of beam cells and improve spectral efficiency. Simulation results show that our proposal significantly improves service satisfaction compared with baselines, where the average data queue length of beam cells is reduced by over 50% with affordable handover frequency.

Beam Management in Low Earth Orbit Satellite Communication With Handover Frequency Control and Satellite-Terrestrial Spectrum Sharing

TL;DR

This paper forms a practical beam management problem, aiming to maximize the long-term service satisfaction of cells, and decomposes it into three subproblems, including inter-satellite handover decision, beam hopping design and satellite-terrestrial spectrum sharing.

Abstract

To achieve ubiquitous wireless connectivity, low earth orbit (LEO) satellite networks have drawn much attention. However, effective beam management is challenging due to time-varying cell load, high dynamic network topology, and complex interference situations. In this paper, under inter-satellite handover frequency and satellite-terrestrial/inter-beam interference constraints, we formulate a practical beam management problem, aiming to maximize the long-term service satisfaction of cells. Particularly, Lyapunov framework is leveraged to equivalently transform the primal problem into multiple single epoch optimization problems, where virtual queue stability constraints replace inter-satellite handover frequency constraints. Since each single epoch problem is NP-hard, we further decompose it into three subproblems, including inter-satellite handover decision, beam hopping design and satellite-terrestrial spectrum sharing. First, a proactive inter-satellite handover mechanism is developed to balance handover frequency and satellite loads. Subsequently, a beam hopping design algorithm is presented based on conflict graphs to achieve interference mitigation among beams, and then a flexible satellite-terrestrial spectrum sharing algorithm is designed to satisfy the demands of beam cells and improve spectral efficiency. Simulation results show that our proposal significantly improves service satisfaction compared with baselines, where the average data queue length of beam cells is reduced by over 50% with affordable handover frequency.
Paper Structure (28 sections, 2 theorems, 36 equations, 9 figures, 2 tables, 3 algorithms)

This paper contains 28 sections, 2 theorems, 36 equations, 9 figures, 2 tables, 3 algorithms.

Table of Contents

  1. Introduction
  2. Related works
  3. Inter-satellite handover
  4. Beam hopping
  5. Satellite-terrestrial spectrum sharing
  6. Motivation and contribution
  7. SYSTEM MODEL
  8. Network model
  9. Interference mitigation strategies to achieve spectrum sharing in LEO satellite networks
  10. Inter-beam interference mitigation strategy
  11. Satellite-terrestrial interference mitigation strategy
  12. Problem Formulation And Transformation
  13. Problem constraints
  14. Problem formulation
  15. Problem transformation
  16. ...and 13 more sections

Key Result

Lemma 1

The inter-satellite handover frequency constraints (eq:handover_constraint) can be replaced by queue stabilization constraints.

Figures (9)

  • Figure 1: The concerned LEO satellite network scenario.
  • Figure 2: The process of the proposed satellite-terrestrial interference mitigation strategy to achieve spectrum sharing.
  • Figure 3: Beam management problem decomposition framework.
  • Figure 4: An example of a network scenario and corresponding conflict graph.
  • Figure 5: The figures are the results of the performance of inter-satellite handover decision algorithms, where (a) presents the objective value of problem $\boldsymbol{P}_o$, (b) is the result of average data queue length of beam cells, and (c) shows the average inter-satellite handover frequency of all beam cells.
  • ...and 4 more figures

Theorems & Definitions (4)

  • Lemma 1
  • proof
  • Lemma 2
  • proof