Rapid-Acquisition Digital Data Modem for High Data Rate Burst/CW Communications

The primary objective of the proposed project is to demonstrate through detailed simulation, performance and low-cost feasibility of SICOM's innovative rapid-acquisition digital data (RADD) demodulator for high data rate burst or CW communications. The demodulator incorporates several innovative features, including zero-preample determination of symbol timing, carrier phase, and carrier frequency for coherent demodulation, a unique carrier-insensitive symbol-timing alignment algorithm, and powerful concatenated coding techniques combining rotationally-invariant pragmatic trellis-coded modulation (inner code), and Reed-Solomon coding (outer code). Feasibility assessment, based on simulations and studies described in this proposal includes evaluation of the design versus existing and planned burst communication links, determination of the effectiveness of coding and interleaving and synchronization, achievement of coherence of the first bit, and "burst learning curves" of BER versus time from burst-start. Secondary objectives of the project include preparation of specifications for a modem to be designed and fabricated in Phase I, including an ASIC implementation of a RADD demodulator, and definition of a detailed implementation plan for Phase II and III. As currently envisioned, the RADD demodulator will accommodate QPSK, 8PSK, and 16QAM, will support 155 Mbps data links, and achieve a 10 to the 10th bit-error-rate with a 7 dB SNR. Anticipated Military Benefits: The proposed project will directly benefit the DoD's development of a global, survivable communications system integrated with commercial worldwide communications. These communications will include 155 Mbps wireless links which will utilize ATM cell-based (burst) technology toward which the RADD modem is targeted. For the tactical battlefield, it is vitally important to transmit and receive data with burst transmissions at high rates; the associated features of low-probability-of-detection and anti-jam operation are crucial for survival. Commercial applications include: Terrestrial and undersea cable/fiber network linking and restoration, private wide-area communications networks for businesses, business campus and local loop wireless