Modified CSMA/implicit token passing algorithm for MIL-STD-188-220B

Media access control (MAC) algorithms have been shown to be critical components in the overall efficiency of military radio communication networks. Many papers at the three most recent MILCOM conferences have focused on combat net radios or ML-STD-188-220B. Several of these compared different MAC algorithms for data only and data and voice networks. The MAC algorithm with the best performance characteristics for a wide class of moderately sized networks appears to be deterministic adaptable priority network access delay (DAP-NAD). The DAP-NAD algorithm can be viewed as a modified implicit token passing algorithm. This paper presents a number of significant extensions and modifications to DAP-NAD, including efficient integration of data and voice. The token passing scheme is modified so that the token effectively jumps over stations that may have transmitted in the last period and allows heavily used nodes or "higher priority nodes" to have increased transmission opportunities. These modifications are shown to have markedly improved performance for the standard tactical Internet division and below (TIDB) network used to compare other MAC algorithms as well as on 16 node randomly loaded networks. Our modifications to DAP-NAD have further enhanced its ability to handle both data and voice efficiently, which is recognized by calling the MAC algorithm data and voice network access delay (DAV-NAD).