The integrated waveform, a proposed improvement to the UHF SATCOM DAMA standards

The Joint UHF MILSATCOM Technical Working Group (TWG) is in the process of developing a single integrated waveform with the goal of providing a significant improvement over the two current demand-assigned multiple access (DAMA) waveforms. This paper describes key features and benefits of the waveform under development and describes several suggestions for improving the waveform that the authors believe should be considered by the TWG. Suggested improvements include a proposed alternative to the various data structures for control channel orderwire bursts, and protocol improvements that would reduce slot-conflict problems for half-duplex terminals, provide a mechanism to accommodate operation over multiple satellites in the same coverage area, provide more effective methods for satellite range determination, and reduce network overhead by including terminal status within ranging bursts sent by terminals. The integrated waveform (IW) will extend the slave channel concept introduced by MIL-STD-188-183A by transmitting forward orderwire (FOW) bursts on selected control channels while user communication can be allocated to any available satellite channel. By eliminating the predefined time-slot frame formats used by MIL-STD-188-183, and by using the multi-h continuous phase modulation (CPM) developed for MIL-STD-188-181B, the IW can more than double the number of circuits that the existing satellite constellation can support. To gain user support, however, the IW has to do more than just increase the number of available services; it must also make communications easier and more reliable. The current DAMA waveforms already greatly increase the number of circuits that UHF SATCOM can support, but that capacity increase has not resulted in tremendous user support for DAMA. Without user acceptance, the IW will not be able to achieve the capacity increase that it is capable of providing.