Adaptive acquisition collision avoidance multiple access for multihop ad hoc wireless networks

This paper presents a new multiple access control (MAC) protocol called adaptive acquisition collision avoidance multiple access with common-transmission code assignment (AACA-CT) for multihop ad hoc wireless networks. Multiple channels are employed in this scheme. One channel is used as the common channel for mobile users (or nodes) contending to reserve traffic channels by means of request-to-send and clear-to-send (RTS/CTS) dialogue. Other channels are used as traffic channels to transmit traffic packets without collision. With this protocol, resource reservation is flexibly and effectively made on multiple frequency bands, frequency-hopping (FH) codes or direct-sequence spread-spectrum (DSSS) codes by half-duplex radios without any help of powerful base stations (BS) or central controllers and wired backbone networks in an asynchronous fashion. The protocol can solve hidden and exposed terminal problems perfectly as is validated through analysis and numerical results. A comparison among the proposed protocol, IEEE 802.11 MAC protocols and the slotted ALOHA protocol shows that the proposed reservation-based approach has advantages over other protocols.