WIRELESS VEHICULAR COMMUNICATIONS ACCORDING TO VEHICULAR COMMUNICATIONS PROTOCOLS USING RESERVATION TIMES

Embodiments are directed to methods and apparatuses for wireless vehicular communications using different communications protocols. A method includes communicating wirelessly via first vehicular communications circuitry by using a first vehicular communications protocol in which respective messages are sent synchronously. The method further includes, as part of each transmitted message, including data which is consistent with another vehicular communications protocol in which messages are sent asynchronously on behalf of other vehicular communications circuits and which indicates to the other vehicular communications circuits a reservation time for ensuing message subframes. In some embodiments, in addition to or alternatively to the above, the messages are transmitted based upon a fairness criterion associated with a relative extent of frequency-spectrum use involving transmissions according to the first vehicular communications protocol relative transmissions according to the other vehicular communications protocol.