Energy-Efficient UAVs Deployment for QoS-Guaranteed VoWiFi Service.

Area of Science:

• Wireless Communication Networks
• Aerial Robotics
• Network Optimization

Background:

• Providing reliable wireless coverage in open areas using Unmanned Aerial Vehicles (UAVs) is crucial for services like Voice over WiFi (VoWiFi).
• Existing methods often struggle to balance deployment efficiency with energy consumption for dynamic user needs.

Purpose of the Study:

• To formulate and solve the optimal placement problem for UAVs providing VoWiFi service.
• To minimize the ratio of deployed UAVs to energy efficiency, thereby reducing UAVs required per service hour.
• To analyze performance for both unicast and broadcast VoWiFi services across different user densities and area sizes.

Main Methods:

• Formulation of an objective function constrained by coverage and VoIP speech quality.
• Utilization of heuristic search methods: Genetic Algorithms for initial UAV deployment and Particle Swarm Optimization for position updates.
• Simulation and analysis of two service types (unicast and broadcast VoWiFi) in small (100 m²) and large (10,000 m²) areas.

Main Results:

• Drone turnover rate correlates with user sparsity and users per UAV.
• For unicast VoWiFi, UAVs per hour increase with user sparsity; radio power is 14-16% of total energy.
• In large areas, higher UAV altitudes increase coverage but also hovering energy consumption.
• Broadcast VoWiFi requires fewer UAVs, consumes 20-75% less power, and is less sensitive to user numbers due to scarce traffic and coverage constraints.

Conclusions:

• The optimal UAV placement strategy effectively balances coverage, speech quality, and energy efficiency for VoWiFi.
• Broadcast VoWiFi services are significantly more energy-efficient and require fewer UAVs compared to unicast services.
• UAV altitude and user distribution are key factors influencing energy consumption and deployment strategies.