Pseudo-Broadcast: An Alternative Mode of Vehicular Communication for Platooning

The platooning application has a significantly higher safety messaging rate requirement that could threaten harmonious coexistence with nearby non-platoon vehicles. We explore an alternative delivery mode for platoon communication in order to address the issue. The proposed mode is called pseudo-broadcast, since it emulates broadcast using unicast. In pseudo-broadcast, the platoon member with the worst reception condition is designated as the destination of the unicast from the leader vehicle. Then other platoon members promiscuously receive the unicast packet. And vice versa, the messages from the platoon followers to the leader are pseudo-broadcast to the leader. The unicast transmission in pseudo-broadcast allows timely retransmission, which is not possible with broadcast. It not only improves the reliability of platoon communication, but also helps minimize the additional beaconing activity in meeting the required latency bound. Consequently, it lessens the abusive bandwidth impact on the non-platoon vehicles in the vicinity, fostering harmonious coexistence. To the best of our knowledge, this is the first work that looks in detail into the question of coexistence between platooning vehicles and others sharing the same channel, and also provides some first insights into its quantitative effects.