A Multi-rate Congestion Controller for Pedestrian Communication

Pedestrian-to-Everything (P2X) communication can support numerous applications from improving traffic light cycle schedules to increase pedestrian safety. However, challenges, such as limited wireless channel resources and battery power, need to be addressed before mass deployment of these systems. In this paper, we introduce a distributed channel congestion control algorithm for Personal Safety Messages (PSMs) that can converge in heterogeneous application environments with different message rates. Different message rates arise, for example, with contextual transmission policies (CTP) that activate different applications based on situational context, such as the estimated positioning accuracy. To minimize channel sensing energy usage, we further propose a novel collaborative channel load measurement mechanism. To evaluate these proposals, we simulate a dense pedestrian scenario in ns-3 with heterogeneous message rates. The simulations show that the proposed algorithm converges and improves the information age for P2X safety applications while reducing energy consumption by 90% compared to existing vehicle-to-vehicle congestion control algorithms.