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NetSim

This package is a network simulator. It is designed to create simulated packet loss and delay in the incoming message topics and simulate the network status.

Download NetSim

Dependencies

ROS dependency

Build

  • Install ROS2 and clone the v2x_msgs and autoware_auto_msgs into the src directory of a ROS2 workspace.

  • Clone the repository into your ROS2 workspace's src folder: 

    git clone --recurse-submodules git@github.com:hoosh-ir/net_sim.git

  • Source your ROS2 Humble: 
    source /opt/ros/humble/setup.bash
  • From the root of your workspace, use colcon to build the package: 
    colcon build --symlink-install

Run

  • From the root of your workspace, source your ROS2 workspace: 
    . install/setup.bash
  • Configure the network simulator by modifying the parameters in the config file config/net_sim_conf.yaml.
  • Launch the application: 
    ros2 launch net_sim net_simulator.launch.py

Configure

Network Simulation Configurations

The net_sim_conf.yaml file located at config provides various configurations for the network simulator. Below, you'll find a list of the options:

  • network_status_type: This parameter determines the type of the network status and can take the following values:

    • 0 (None): This value determines there are no delays or packet losses for the incoming topics.
    • 1 (Constant): In this mode, the simulator creates constant delay and packet loss for the message topics.
    • 2 (Heatmap): In this mode, the simulator reads a CSV file associated with a given network heatmap and creates delays and packet losses for the incoming message topics based on the heatmap values.

  • const_network_delay: This parameter determines the amount of constant delay (in milliseconds) to create for the incoming messages (Used only when the network_status_type is set to 1).

  • const_network_packet_loss: This parameter determines the amount of constant packet loss (in percent) to create for the incoming messages (Used only when the network_status_type is set to 1).

  • prediction_network_status_file: This parameter gives the absolute address of the heatmap file for the object prediction topic (Used only when the network_status_type is set to 2).

  • prediction_network_status_involved_stations: This parameter lists the IDs of the RSUs involved in the heatmap file for the object prediction topic (Used only when the network_status_type is set to 2).

  • traffic_signal_network_status_file: This parameter gives the absolute address of the heatmap file for the traffic signal topic (Used only when the network_status_type is set to 2).

  • traffic_signal_network_status_involved_stations: This parameter lists the IDs of the RSUs involved in the heatmap file for the traffic signal topic (Used only when the network_status_type is set to 2).

  • freespace_network_status_file: This parameter gives the absolute address of the heatmap file for the freespace topic (Used only when the network_status_type is set to 2).

  • freespace_network_status_involved_stations: This parameter lists the IDs of the RSUs involved in the heatmap file for the freespace topic (Used only when the network_status_type is set to 2).

Topic Configurations

Similarly, the topic_conf.yaml file in the config folder, provides the means to configure the package for the input/output topics. The parameters are listed below:

  • input_objects_topic
  • output_objects_topic
  • input_signals_topic
  • output_signals_topic
  • input_freespaces_topic
  • output_freespaces_topic
  • vehicle_pose_topic

Network Heatmap

When simulating the network status based on some given heatmap file, the provided file must abide by the format rules below:

  • The heatmap file must be a COMMA-SEPARATED VALUES file
  • The heatmap file must NOT include any descriptive headers
  • The values must be in the order x,y,z,rsu_1_delay,rsu_1_packet_loss,rsu_2_delay,rsu_2_packet_loss,...

You can refer to a sample heatmap file located in the sample folder.

Custom Messages

You can assign NetSim custom messages of your own. For this purpose, you need to adjust a few things in the NetSim codebase and rebuild it.

In the following sections, we'll explain the requirements and modifications to custom messages.

Custom Message Format Requirements

Let's assume you have a message type other than those supported by NetSim. Let's name this message CustomMessage. To simulate the network passing such messages, you need to create a cooperative message type containing your CustomMessage. We call that CooperativeCustomMessage. The fields inside CooperativeCustomMessage must include:

uint64 station_id
uint64 sensor_type
geometry_msgs/PoseStamped station_pose
custom_package/CustomMessage custom_message

station_id is the ID of the RSU (or OBU) sending the message, sensor_type is the type of the sensor used to obtain the messages (not yet defined). station_pose is the whole pose of the transmitting RSU (or OBU) and custom_message is your desired message.

Note

The CustomMessage type can be any of the ROS built-in message types or from any custom_package created by third parties.

Modification to NetSim Codebase

To have NetSim transmit the external message types, you need to make NetSim identify, subscribe to and publish them. We've provided the means for you just to make slight alterations.

In the source code, under src, you need to modify the net_simulator.cpp file. There are three sections identifiable by the phrase Custom message section. Under each section, there are commented code snippets. You need to uncomment and modify them according to the name of your package and message type.

  • The first section includes the message types. Modify according to your package and message type names
  • The second section defines the variables needed to simulate the message. In this section, be wary of the name you pass to the network reporter node ("custom_message" by default). This name must repeat in config/net_sim_conf.yaml. Also, make sure you pass the proper input and output topic names to the sender ("/output_custom_message" by default) and the receiver ("/input_custom_message" by default) nodes.
  • The last section passes the created ROS nodes to the multithreaded executor.

Modification to NetSim Config Files

After uncommenting and modifying commented code snippets, you need to modify config/net_sim_conf.yaml. Again, we've provided two commented sections (search "Custom message section" in the file) for you to uncomment and modify according to your needs.

Modification to CMakeLists.txt

In the CMakeLists.txt, refer to Custom message sections: - In the first section, add your CustomMessage and CooperativeCustomMessage packages as needed. - In the second section, link your custom packages to NetSim's libraries.

Modification to package.xml

In package.xml refer to the Custom message section, uncomment its section and modify it according to the names of your CustomMessage and CooperativeCustomMessage packages.

Build NetSim

After the above steps, rebuild NetSim to reflect the changes made. Make sure to place your CustomMessage and CooperativeCustomMessage packages in the same workspace as net_sim to build together. Follow the build instructions to build the workspace.