duplicated DENM messages

[Ambica2022]

Hi,

I noticed that DENM message is received multiple number of times by the receiver even though it is sent only once by the sender. For example
denmsent : 1 (Vehicle 1) denmreceived : more than 15....all 15 are with same denmactionId but at different times(Vehicle 2)

Any clue on this?Thanks in advance.

Regards, Ambica

[riebl]

All received DEN messages are passed to the DEN service, including those received by forwarding stations. Thus, it is perfectly normal that you receive the same DEN message multiple times. Other than CAMs which are "single hop broadcast" (SHB), DENMs employ the GeoBoardcast (GBC) mechanism to enhance the coverage. However, the ETSI ITS-G5 standard has some flaws regarding the Contention-Based Forwarding (CBF) algorithm used by default for GeoBroadcast. One effect is a rather poor rejection rate of duplicate messages.

[Ambica2022]

Hi Raphael,

Thank you for the information.Observed that there is no pattern following for the number of duplicate DENM messages received by each vehicle.Please check the screenshot attached.

So,I hope i can consider only the first received DENM message and the time at which it received to analyse the results.

Best Regards, Ambica

[riebl]

Yes, only the first reception of a distinct DENM message is usually relevant. The "pattern" depends on many aspects such as the network topology, vehicle density, and channel congestion.

[Ambica2022]

Thank you