ROSNS3: A Network Simulator (NS-3) bridge for Robot Operating System (ROS)

This is an NS-3 extension for ROS that allows to simulate network aspects of a robot swarm. Briefly, NS-3 is an event simulator to design and implement network models. ROSNS-3 allows to

• Simulate wireless signal attenuation,
• Perform network packet routing,
• Calculating recieved signal strength (RSS) between nodes,
• Retrieve updated routing tables in real-time.

Consider citing our work [1] if you find this code helpful for your publications.

System Overview

• The ROS and NS-3 environments simulate the robots’ movements, and the network events, respectively.
• ROSNS3 establishes the communication between the two environments using the UDP.
• Currently, to calculate the routing paths as the robots move, we use Optimized Link State Routing (OLSR) algorithm.
• RSS and throughput features are planned for future work.

Run ROSNS3

Clone ROSNS3

Clone ROSNS3 to your catkin_ws/src using the command below.

• git clone --recursive git@github.com:malintha/rosns3.git

ROSNS3 relies on both the client and server modules. To avoid having to install bulky NS-3 software, we have provided a dockerized version of the ROSNS3 server. Unless you need to change the server code, which resides at rosns3_server there is no need to explicitly build it.

• Download the docker image by running docker pull malinthaf/rosns3-server:latest.

You can change the propagation loss model parameters for wireless communiation inside the run_server.sh script. These changes will subsequently applied to the server running inside the docker container.

Build ROSNS3 Client

• Simply run catkin build rosns3_client.

Run

• Run ./run_server.sh to run the server.
• By default, the rosns3_server will run on the UDP port 28500.
• Run the client with command roslaunch rosns3_client rosns3_client.launch n_backbone:=5 to simulate the adhoc wireless communication in a robot swarm of 5 nodes.
• To stop the server run stop_server.sh script. This will kill the ROSNS3 server, stop the docker container, and remove the it from memory.

Usage

• ROSNS3 uses rostopics to obtain the swarm's physical state from the ROS-enabled physics simulator. More specifically, in your simulation platform each robot can publish its state to the topic /robot_<robot_id>/current_state. For now you can use the message type rosns3_client/Waypoint for the communication. In future releases we plan to change this to a more generic ros_std type.
• Internally, the client aggregates the robots' states periodically and communicates it to the server using a flatbuffers message type.
• The server calculates the current communication topology of the swarm using the Friis wireless channel model and OLSR routing, and publishes it to the topic /rosns3_client/routing_table.
• Each entry in the routing table corresponds to the adjacency matrix, and specifies the number of communication hops between the two given robots in the swarm.

References

    [1] @ARTICLE{9739846,
        author={Fernando, Malintha and Senanayake, Ransalu and Swany, Martin},
        journal={IEEE Robotics and Automation Letters}, 
        title={CoCo Games: Graphical Game-Theoretic Swarm Control for Communication-Aware Coverage}, 
        year={2022},
        volume={7},
        number={3},
        pages={5966-5973},
        doi={10.1109/LRA.2022.3160968}}