3-D Spread Spectrum Communication for High Threat Environments

In phase I SBIR, SiComm studied the technical feasibility and performance of a three dimensional multi input multi output, orthogonal frequency division multiplexing, direct sequence spread spectrum (MIMO-OFDM-DSSS) modem. MIMO techniques combined with OFDM and DSSS create a virtually untapped space where anti-jamming, low probability of detection/interception (AJ/LPI/LPD) can be achieved at high data rates. As part of the Phase II activity, SiComm will build a highly reconfigurable MIMO OFDM prototype unit that will implement the novel architecture identified in Phase I. Field testing of the unit will allow us to demonstrate the superior performance of MIMO systems for military communications. Moreover, it will pave the way for introduction of this technology into the military arena. Simulations have shown that with the 4x4 MIMO configuration that SiComm intends to build as part of phase II effort, data rates of up to 500 Mbps are attainable. Data security is enhanced due to the three dimensional randomization that occurs in space, frequency and time via MIMO, OFDM and DSSS, respectively. The proposed prototype will support variable bandwidths from 1 MHz to 25 MHz at the 2.4 GHz band, with MIMO configurations up to 4x4. To ensure robustness, the system will operate with a very low intermediate frequency (VLIF) with the final conversion to baseband performed in the digital domain, thus enabling advanced signal processing filtering techniques to be applied. Furthermore, the portability of the unit will allow field tests under a host of wireless channel conditions with on board resources available to support a variety of network protocols.