A simple example with the 2.4GHz Phy

After you have fetched and built all simulator components, you can run a simple example as follows.

Note: Here we assume ${BSIM_OUT_PATH} is the path where the simulator compile output is stored. In the previous examples this was ~/bsim/

cd ${BSIM_OUT_PATH}/bin
./bs_2G4_phy_v1 -s=hello_world -D=2 -sim_length=50e6 &
./bs_device_handbrake -s=hello_world -d=0 -r=10 &
./bs_device_time_monitor -s=hello_world -d=1 -interval=100e3

In this simple example:

• “hello_world” is used as the simulation identification string.
• The 2.4GHz Phy is told that 2 devices will connect to it.
• We also tell the Phy to stop the simualtion after 50 seconds (50e6 microseconds)
• The handbrake device is run as the first (-d=0) device which connects to the Phy. This device slows down a simulation to a given real time speed ratio. In this case, we set the ratio to 10x with -r=10.
• The time monitor device is run as the second (-d=1) device in the simulation. This device will monitor the speed of the simulation. We configure it to monitor with a 100ms interval (-interval=100e3).

As you can see, each of these devices is a separate program, run independently. Each of them could have been run from a separate terminal. All that is required for them to find each other, is that they are run by the same user, in the same workstation, and share the simulation ID string.

Note that until the last device has joined the simulation, the Phy is blocking the 1st device as neccessary. So devices can be started at arbitrary times without affecting the result.

Now let’s make a mistake:

./bs_2G4_phy_v1 -s=hello_world -D=2 -sim_length=50e6 &
./bs_device_handbrake -s=hello_world -d=0 -r=10 &
./bs_device_time_monitor -s=hello_world -d=0 -interval=100e3 &

As you can see, both devices are assigned the same number. The 2nd device will realize about this, warn you, and stop. But, the phy and the 1st device, are still waiting for the simulation to start.

Stoping a running/pending simulation

When running complex simulations with a multitude of devices, if some device crashes at boot, or some mistake is done it can be tedious to fix. Instead you may want to simply stop all running simulation components. You can do that with the stop_bsim.sh script. You will find it in ${BSIM_COMPONENTS_PATH}/common/stop_bsim.sh. You can either run the script directly, which will stop all your ongoing simulations, or provide to it a simulation ID as its only paramter, in which case it will only stop the processes linked to that simulation.