The Performance Analysis of Spectrum Sharing between UAV enabled Wireless Mesh Networks and Ground Networks (2311.14988v1)

Abstract: Unmanned aerial vehicle (UAV) has the advantages of large coverage and flexibility, which could be applied in disaster management to provide wireless services to the rescuers and victims. When UAVs forms an aerial mesh network, line-of-sight (LoS) air-to-air (A2A) communications have long transmission distance, which extends the coverage of multiple UAVs. However, the capacity of UAV is constrained due to the multiple hop transmissions in aerial mesh networks. In this paper, spectrum sharing between UAV enabled wireless mesh networks and ground networks is studied to improve the capacity of UAV networks. Considering two-dimensional (2D) and three-dimensional (3D) homogeneous Poisson point process (PPP) modeling for the distribution of UAVs within a vertical range {\Delta}h, stochastic geometry is applied to analyze the impact of the height of UAVs, the transmit power of UAVs, the density of UAVs and the vertical range, etc., on the coverage probability of ground network user and UAV network user. Besides, performance improvement of spectrum sharing with directional antenna is verified. With the object function of maximizing the transmission capacity, the optimal altitude of UAVs is obtained. This paper provides a theoretical guideline for the spectrum sharing of UAV enabled wireless mesh networks, which may contribute significant value to the study of spectrum sharing mechanisms for UAV enabled wireless mesh networks.

• The paper establishes that UAV altitude is critical for maximizing transmission capacity and coverage using stochastic geometry models.
• It demonstrates that increased UAV density heightens interference for ground users, while directional antennas significantly improve performance.
• Numerical simulations validate an optimal UAV altitude, providing practical guidelines for enhancing spectrum sharing in disaster recovery and urban deployments.

The Performance Analysis of Spectrum Sharing between UAV Enabled Wireless Mesh Networks and Ground Networks

The paper "The Performance Analysis of Spectrum Sharing between UAV Enabled Wireless Mesh Networks and Ground Networks" provides a rigorous examination of spectrum sharing between Unmanned Aerial Vehicle (UAV) enabled wireless mesh networks and terrestrial networks. UAVs offer extensive coverage and deployment flexibility, making them valuable in disaster management for maintaining wireless services. However, aerial mesh networks involving multiple UAVs suffer from capacity limitations due to multi-hop transmissions. The investigation focuses on leveraging spectrum sharing to enhance the capacity of UAV networks by co-opting the spectrum assigned to ground networks.

Key Contributions

The paper leverages stochastic geometry to analyze the impact of various deployment parameters of UAVs on the coverage probability for both UAV and ground network users. The models considered include two-dimensional (2D) and three-dimensional (3D) homogeneous Poisson point processes (PPPs) to simulate the distribution of UAVs. Key influencing factors such as UAV height, transmit power, density, and vertical range are meticulously examined. Moreover, the paper validates the performance improvement introduced by using directional antennas for spectrum sharing.

A major outcome of the paper is the derivation of an optimal altitude for UAV deployment, aimed at maximizing the transmission capacity while ensuring satisfactory coverage probability for terrestrial network users.

Numerical Analysis and Results

The paper provides strong numerical evidence of the theoretical findings. The core results are as follows:

1. Coverage Probability Analysis: The coverage probability of ground and UAV network users was computed analytically and validated through extensive Monte Carlo simulations. A notable observation is that the coverage probability, $P_1$, is a unimodal function of UAV height, indicating an optimal height where $P_1$ peaks before declining due to increased likelihood of Line-of-Sight (LoS) interference.
2. Impact of UAV Deployment Density: The paper demonstrates that an increase in UAV density reduces the coverage probability for ground users due to heightened interference, although spatial separation aids in mitigating some of this effect.
3. Directional vs. Omnidirectional Transmission: The utilization of directional antennas significantly enhances both the coverage probability and the transmission capacity of the UAV network. This improvement becomes more pronounced with increased UAV height and density.
4. Optimal UAV Altitude: The paper computes the optimal UAV altitude that maximizes the transmission capacity of the UAV network under the coverage constraint for ground users. Specifically, when directional antennas are employed, this optimal altitude can mitigate interference more effectively, allowing for better spectrum sharing.

Theoretical and Practical Implications

From a theoretical standpoint, the paper enriches the understanding of spectrum sharing dynamics in heterogeneous networks involving both UAVs and ground users. The application of stochastic geometry to model such networks provides a robust framework for further research in this domain.

Practically, the findings can guide the deployment of UAV mesh networks in scenarios that require rapid and flexible communication setups, such as disaster recovery operations. Operators can use the derived optimal altitude and antenna configuration guidelines to ensure resilient and efficient communication services.

Future Directions

The evolving landscape of UAV-enabled communications suggests several avenues for future research:

1. Advanced Spectrum Management Techniques: Exploration of machine learning algorithms for dynamic spectrum allocation could further enhance the efficiency of spectrum sharing.
2. Integration with 5G Networks: Investigating the coexistence and integration of UAV networks with emerging 5G infrastructures will be crucial for future smart city applications.
3. Energy Efficiency Optimization: Given the power constraints of UAVs, developing energy-efficient protocols that complement the spectrum sharing mechanisms outlined in this paper will be essential.
4. Urban Deployment Considerations: Extending the analysis to consider urban environments with high-rise buildings which affect A2G link characteristics would provide more comprehensive deployment guidelines.

In summary, the paper offers substantial theoretical insights and practical recommendations for enhancing the performance of UAV-enabled wireless mesh networks through effective spectrum sharing with ground networks. The application of stochastic geometry, combined with empirical validation, underpins the robustness of the conclusions drawn. This work lays a strong foundation for continued innovation and optimization in UAV communication systems.