Drone Swarm Communication over TDMA MANET and Satellite

Overview

This simulation models a tactical drone swarm communication system that integrates both TDMA-based MANET radios and satellite links. Each drone is equipped with two communication interfaces—one for MANET connectivity over the C-band and another for satellite communication over the X-band. The scenario represents a real-world military setup in which communication happens simultaneously across both interfaces. The central command server transmits Command & Control (C2) data to all drones via the satellite link at a rate of 25 kbps. In return, each drone sends Telemetry and Status Reports to the server every 3 seconds at 50 kbps, also via the satellite link. At the same time, drones exchange Intra-swarm Coordination data among themselves over the TDMA-based MANET, using direct or multi-hop communication paths. As drones follow predefined mobility paths, the network automatically updates the MANET routes to ensure consistent inter-drone connectivity. The system’s performance is analyzed in terms of end-to-end latency and throughput under dynamic, mobility-driven topology changes.

Network Scenario

Network Drone
Figure 1: 5 drones; 1 satellite; 1 satellite gateway; 1 server. Each drone has a TDMA radio interface and a satellite interface. Link-4 is a logical TDMA ad hoc link.

Network Setup

  • Communication Range: 150 km for TDMA radios
  • Network: 5 drones, 1 satellite, 1 Gateway, 1 Central Server
  • X-Band Satellite Communication
    • The server transmits Command & Control (C2) data to the drones at 25 kbps via the satellite link.
    • The drones transmit Telemetry & Status Reports to the server at 50 kbps, every 3 seconds, via the satellite link.
    • X-band is used for both forward and return Satellite Communication.
  • C-Band MANET communication
    • Node N1 transmits Intra-swarm Coordination data to Node N5 at 10 kbps over the TDMA link.
    • Drone Communication Range (MANET): 150 km.
    • C-band is used for TDMA-based MANET communication.
  • Drone Mobility Configuration
    • N5 and N9 move northeast at 0.4 m/s and 0.9 m/s.
    • N7 and N8 move east at 0.4 m/s and 0.9 m/s.
    • N6 moves southwest at 0.4 m/s.
  • Mobility Configuration: File-based mobility for predefined flight path
    Direction
    Figure 2: Initial Position and Velocities. NetSim assumes that nodes have appropriate Doppler compensation mechanisms

Routing Transitions Due to Mobility


Time Interval Communincation Path Type
0s – 191sN5 > N9Direct
198s – 318sN5 > N6 > N9Multi-hop
324s – 900sN5 > N7 > N9Multi-hop
Table 1: Time Intervals and Routing Paths Between N5 and N9

System Parameters: Satellite


Parameter Value
Satellite TypeGEO
ModulationQPSK
Coding Rate3/4
Frequency (GHz)7.9 for forward, 7.25 for return
Bandwidth (MHz)1
Roll of Factor1
Spacing Factor1
Symbol per slot90
Pilot block size (Symbols)36
Slot count in frame360
Pilot header (Slots)1
Pathloss modelFriis free space
Table 2: Satellite System Parameters

System parameters: MANET


Parameter Value
Routing protocolOLSRv1-RFC 3626
Slot allocationRound robin
Bandwidth (KHz)20
Data Symbol Rate (Kbd)1000
Pathloss modelRange based
Range (km)150
Transmit power (W)20
ModulationQPSK
Coding Rate1/2
Table 3: MANET System Parameters


Understanding the multi-hop Routes taken through Animation

Network Drone
Animation

Results

On analysing NetSim’s packet trace log file we observe the multi-hop routes as shown in the table below:
  • 0s to 191s: Direct communication (N5 → N9)
  • 198s to 318s: Multi-hop communication (N5 → N6 → N9)
  • 324s to 900s: Multi-hop communication (N5 → N7 → N9)

Throughput vs Time

Network Drone
Figure 3: Throughput remains stable initially due to direct communication. A drop occurs at 191-198s due to mobility and a path change. Another drop happens at 319-324s due to a subsequent path change.

Latency vs Time

Network Drone
Figure 4: Low latency initially due to direct communication (up to 190s). A latency peak occurs at 191-198s due to mobility and a path change. Another peak is observed at 319-324 due to a subsequent path change. Latency remains higher afterward due to multi-hop communication.

Satellite communication: Latency. QPSK vs QAM

Network Drone
Figure 5: Average latency for the QPSK is greater than the average latency of 16-QAM.


The simulation results show that 16-QAM modulation achieves significantly lower average latency compared to QPSK, especially in the Drone-to-Server communication direction. With 16-QAM, the target latency of less than 1 second (1000 ms) is achieved on average, with an overall mean latency of 700.68 ms across five applications, making it suitable for time-sensitive telemetry transmissions from drones.