A Reliable Multicast MAC Protocol with LPD Capability for Tactical Ad-Hoc Networks

We propose a reliable multicast MAC protocol for channel efficiency and LPD (low probability of detection), a capability that enhances survivability, assisted by multicarrier direct-sequence code-division multiple access (MC-DS/CDMA) scheme in tactical ad-hoc networks. For a reliable multicast based on IEEE 802.11 standards constructing RTS-CTS handshake, a multicast sender has to receive consecutive CTSs and ACKs from all multicast receivers. These cumulative CTSs and ACKs degrade network efficiency. Furthermore, the cumulative signals of CTSs and ACKs can be easily detected by an enemy detector. In the proposed protocol, CTS/ACK messages can be transmitted concurrently through the MC-DS/CDMA mechanism. This can reduce the transmission overhead generated by consecutive CTSs and ACKs. Also, the cumulative signal strength of CTSs/ACKs can be reduced, since the mechanism can spread CTS/ACK transmission power by spreading gain of the MC-DS/CDMA code. The proposed protocol is thoroughly examined by theoretical methods and simulation. Results show that it significantly improves the performance and the survivability of tactical ad-hoc networks.