Evaluation of Mechanisms for Reliability and Awareness in Platooning Under Low Transmit Power

ABSTRACT

Low transmit power operation, whether caused by transmit power control or set deliberately to reduce interference, improve coexistence or save energy, can undermine the awareness range and beacon reliability required for safe vehicle platooning. This paper examines that safety risk under persistent low transmit power and evaluates mechanisms that can recover reliability and situational awareness. Using simulations, safety is assessed via observed crash rate and near‐crash inter‐vehicle distance, while communication overhead is captured through channel busy ratio. We show that low transmit power is safe at low traffic density, but becomes unsafe in dense traffic. We then systematically evaluate reliability mechanisms spanning deterministic scheduling overlays (slotted and inter‐platoon grouped slotted), redundancy, acknowledgement‐triggered retransmission, contention window tuning, clear channel assessment threshold selection and role‐based transmit power settings. Results indicate that no individual mechanism is sufficient under very low power without trade‐offs. However, an appropriate combination (inter‐platoon scheduling, higher power leaders and moderate contention tuning) improves safety with limited overhead. Finally, we demonstrate that the baseline balancing awareness and congestion with variable transmission power approach to far‐range awareness is unsafe for platooning and therefore introduce safer extensions that integrate reliability effectively.