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I am currently working on evaluating the effects of communication load on generation of Cooperative Awareness Messages. For this, I am using Artery with veins for simulating the 802.11p stack. From my simulation, I observed that I was only getting an effective communication range of about 100m using the default communication parameters given in Config veins in the omnetpp.ini file. After going through other related questions like, (Change the transmission signal strength for a specific set of vehicles during the run-time), I know that increasing the value of *.node[*].nic.mac1609_4.txPower should help in increasing the communication range. However, I am not noticing any change in the observed communication range by either increasing or decreasing this value.

Since I am quite new in using Artery with Veins, I am not sure if there is something else that we need to do for increasing the communication range of the vehicle.

Just a bit more detail on how I am calculating the communication range. I have two vehicles A and B. I have set the speed of vehicle A to be 4m/s and Vehicle B to 0.01 m/s (such that it is almost at standstill). Based on the CAM generation conditions both vehicles at these speeds would generate a message every second. I have a straight road segment of 700m with two lanes and both the vehicles are generated at the same time in lanes 0 and 1 respectively. Based on the speed of vehicle A, it should take 175s for Vehicle A to leave the road segment. Observing the generated .sca file at the end, I see that the ReceivedBroadcasts + SNIRLostPackets = 28 for both the vehicles meaning that only for the first 28s (28*4 = 112m) both the vehicles were at range. I tried it with different values of txPower and sensitivity but I am still getting the same result.

Thanks for your help

Update

I have added the screenshots of the message that I am receiving during successful packet reception and packet loss due to either errors or due to low power levels.

enter image description here Successful Reception

enter image description here Reception with error

enter image description here No reception

Based on the logs it seems that the packets are lost as the power measured at the reciever side is lower than the minPowerLevel. I have found out that minPowerLevel can be set by changing the value of *.**.nic.phy80211p.minPowerLevel in the omnetpp.ini file, but could someone let me know how the Rx power is calculated (in which file)?

Bas
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  • You might be jumping to conclusions based on only little data. Recording statistics using vectors instead of scalars or running the simulation in GUI mode should give you much better insights into what is happening in your simulation – Christoph Sommer May 24 '21 at 10:43
  • Hello Christoph. Thanks for the reply. I have also recorded statistics using vectors (Tx, RX time stamps, and vehicle positions). Messages are being transmitted correctly throughout the simulation, however, the successful reception stops once the distance between the vehicles increases to above 77m. I wonder if somewhere in Artery or veins, the Tx power is overwritten to the default value as there seems to be no correlation between the Tx power that I set in omnetpp.ini and the Communication range. – Bas May 25 '21 at 08:29
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    Can you post an excerpt from the event log of a simulation run in debug mode? Here, you should be able to see text like `.nic.phy80211p: Received new AirFrame [..] from channel. [..] AirFrame: 1 with (4.63072e-09 > 1e-11) -> Trying to receive AirFrame. [..] Packet is fine! We can decode it [..] packet was received correctly, it is now handed to upper layer... [..] Decapsulating MacPacket from Airframe with ID 1 and sending it up to MAC.` or (alternatively) something like `packet was not detected by the card. power was under minPowerLevel threshold` – Christoph Sommer May 25 '21 at 11:23
  • Thanks Christoph. I have updated my question with the logs. It now looks pretty clear that the packets are not being received because the power detected at the receiver side is lower than the minPowerLevel threshold. Could you let me know if it is possible to reduce the value of this threshold? – Bas May 25 '21 at 12:32

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