The proposed innovation combines a unique turbo-coding algorithm, developed by NASA-JPL, Nyquist pulse shaping, and a breakthrough in phase-coherent modulation, SiQAM, developed by SiCOM. The result will be a high-order modulation turbo-coded modem/codec application-specific integrated circuit (ASIC) which dramatically improves data capacity on bandwidth-limited and power- limited data links. SiQAM optimally matches nonlinear high-power amplifier (HPA) characteristics to minimize HPA peak power requirements. Turbo-coding, a remarkable development in forward-error-correction, substantially improves error rate for any received signal-to-noise ratio, and Nyquist waveforms optimally use available signal bandwidth. The particular form of turbo-coding proposed herein, developed by NASA-JPL, is known as serial concatenated convolutional coding, abbreviated as, "SC3," which will also be used in this proposal. Linking these complementary breakthrough technologies is in itself an innovative breakthrough which reduces the demands on satellite-based HPA technology. In Phase II/III the solution will be designed in low-cost integrated circuit technology which will dramatically provide very high data rate (622 Mbps) bandwidth- and power- efficient low-cost digital modem/codecs.
Potential Commercial Applications:SiCOM currently competes in the high-speed wireless data market with its state- of-the-art modulator and demodulator products (BitFLOW), initiated under a 1996 NASA SBIR project. In the proposed project, SiCOM will prove the feasibility of BitFLOW-SC3 (Serial Concatenated Convolutional Coding) modems, through simulation. Success in this phase will lead to a comprehensive product development program to prototype the BitFLOW-SC3 design in breadboard form, first using SiCOM's BitFLOW 2 modulator and demodulators currently in development, and an FPGA implementation of the SC3 circuitry, followed by development of the BitFLOW-SC3 capability in productized ASIC form, using private funding. The contemplated commercial venture will mirror SiCOM's BitFLOW modem project, where SiCOM won NASA SBIR Phase I and Phase II contracts, and received supplementary funding from SiCOM's own profits and from its financial partner. With completion of the proposed SBIR project, SiCOM will push the state-of-the-art with new "BitFLOW-SC3," products that will outperform any competing product, including BitFLOW, by three to five dB in signal-to-noise ratio for comparable error-rate. This success will enable designers to use much less costly power amplifiers, dramatically enhancing the viability of the NASA architecture in establishing a widespread, high-performance, low-cost role for satellite communications for NASA missions and the many commercial systems currently implementing the NASA architecture for terrestrial broadband wireless access. These products would be used in both space-based (e.g., Spaceway) and terrestrial-based communication systems (e.g., Local Multipoint Distribution System) that must serve next-generation requirements for high-performance data links and data-on-demand. The project will directly support NASA's Direct Digitial Distribution (D3) program.
