Simulation model and studies of MIL-STD-188-220A [protocol]

A detailed model for the analysis and evaluation of many aspects of the protocol MIL-STD-188-220A has been built. This model has been used to develop important results about the performance of MIL-STD-188-220A for various network configurations and message types and loads. The model includes detailed implementations in OPNET of many of the features of MIL-STD-188-220A including Type 1 and Type 2 services, deterministic adaptable priority network access delay (DAP-NAD) and radio embedded network access delay (RE-NAD) media access control algorithms, intranet topology with all appropriate updates, topology requests, and the transmission of all topology messages with the exact size and timing of the messages dictated by the protocol. Blocking of transmissions to individual nodes, either forced by obstructions or partial or total blocking forced by jamming, and intranet relaying using the topology routing tree graph have been implemented and used to obtain results. The model incorporates mobile receiver and transmitter nodes as well as fixed or mobile jammer nodes. The jammer nodes can have isotopic antennas or antennas with dB gains in cones with fixed direction pointing or dynamic direction pointing toward a target. Bit error rate (BER) and correction using the 24/12 Golay algorithm is efficiently modeled at the bit level. We have obtained some quite definitive results about which parts of the MIL-STD-188-220A protocol should be used under various network and message size and frequency configurations. These results should be very useful to the users and potential users of this protocol. Significant comparative results have been obtained as baselines for fire support and situation awareness type messages. We contrast the performance of the networks for the media access control (MAC) algorithms DAP-NAD and RE-NAD for multiple small fire direction subnets and for larger single network configurations. The model has shown the effects of blocking via physical obstructions or jamming on network performance. We have also demonstrated the ability of both DAP-NAD and RE-NAD to continue to efficiently operate on a disconnected network and to eventually reconnect the network when physically possible.