Enhanced Data Rate Performance for VLF/LF

"This Phase II SBIR will develop and demonstrate an integrated setof technologies that allow increased information throughput onVLF/LF radio communications links with minimal impact on thebroadcast network's near-global coverage. The integratedtechnologies include 1) an advanced message compressionmethodology to minimize the number of information bits needed tobe communicated, 2) new forward error correction (FEC) codesbased on state-of-the-art low density parity check coding (LDPCC)with large blocksizes and high rates, and 3) partial response(PR), continuous phase modulation(CPM) with an innovative, low-complexity demodulation algorithm. With various parameters,these technologies can be combined to form enhanced data rate(EDR) communications modes with 2 - 4 times the informationthroughput of current VLF/LF broadcast modes with little or noimpact on the network coverage.BENEFITS: With the successful completion of this Phase II development and demonstration effort, the methodologies, software tools, and real-time algorithms supporting application of advanced message compression, advancedhigh-rate FEC codes, and low-complexity partial response continuous phase modulation/demodulation to bandwidth- and power-limited radio communications links will be demonstrated. This will be particularly applicable to software-defined radios and willhave been validated for use on VLF/LF communications channels in the presence of significant impulsi