ELF signal design

Modulation and coding techniques yielding signaling waveforms suitable for use with the Sanguine ELF Communication system must simultaneously satisfy a number of objectives. These objectives include: (1) providing a very low probability of incorrect message reception, (2) minimizing the required transmitter power by minimizing the required signal-to-noise ratio at a distant receiver, and (3) creating a signal that is difficult to spoof or jam. One suitable combination is the use of minimum shift keyed (MSK) modulation for bandspreading with binary convolutional encoding and antipodal channel symbol modulation. This signal structure in combination with sequential decoding at the receiver requires a bit-energy to effective noise-density ratio of less than 2 dB and hence is exceedingly efficient.