Various arrangements for using multiple air interfaces on a frequency channel for side-link communications are presented. A first indication of a first time-window of a first resource pool may be transmitted by a first air interface system. A second indication of a second time-window of a second resource pool may be transmitted by a second air interface system. Side-link communications may be performed using the first air interface during only the first time-window of the first resource pool. Side-link communications may be performed using the second air interface during only the second time-window of the second resource pool.