ACK for Broadcast Message with 802.11 & 802.11p

Question

I'm aiming to do some Network Simulation (specially VANETs) with Omnet++, Mixim Project & Sumo.

Some one can give me more clarification about broadcasting message with 802.11, i.e what i want to know is "When performing broadcast message, is there any ack with 802.11 ? "

Currently what i know is regarding the 802.11p version who currently didn't perform any ack for broadcasted messages.

Thanks for all guys.

Answer 1

ACKs under 802.11 in general and 802.11p more specifically work as following (for a sender X and one or more recipients Y,Z)

• UNICAST: X sends a message and triggers a timer, Y receives the message and sends back an ACK, if the ACK is lost or not received before timer expiry then X retransmits the frame
• BROADCAST: X sends a message but does not trigger any time. Upon receipt, Y does not send an ACK. Indeed, in Broadcast mode, there are no Timers nor ACKs.