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
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
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 – 191s
N5 > N9
Direct
198s – 318s
N5 > N6 > N9
Multi-hop
324s – 900s
N5 > N7 > N9
Multi-hop
Table 1: Time Intervals and Routing Paths Between N5 and N9
System Parameters: Satellite
Parameter
Value
Satellite Type
GEO
Modulation
QPSK
Coding Rate
3/4
Frequency (GHz)
7.9 for forward, 7.25 for return
Bandwidth (MHz)
1
Roll of Factor
1
Spacing Factor
1
Symbol per slot
90
Pilot block size (Symbols)
36
Slot count in frame
360
Pilot header (Slots)
1
Pathloss model
Friis free space
Table 2: Satellite System Parameters
System parameters: MANET
Parameter
Value
Routing protocol
OLSR
Slot allocation
Round robin
Bandwidth (KHz)
20
Data Symbol Rate (Kbd)
1000
Pathloss model
Range based
Range (km)
150
Transmit power (W)
20
Modulation
QPSK
Coding Rate
1/2
Table 3: MANET System Parameters
Understanding the multi-hop Routes taken through Animation
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
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
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
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.
