This Phase 1 SBIR proposal addresses a new waveform for wireless communications for the US Army's Tactical Radio Communications Systems (TRCS). The evolving digital battlefield will require significantly higher communication data rates to support transmission of voice, video and data. New, spectrally efficient waveforms will be needed to accomplish this in the presence of existing communications systems and radios. With increasing demands on limited RF spectrum, more spectrally efficient waveforms that can withstand in-channel and adjacent channel interference and jamming are required to allow the Army to fully perform its mission on today's digitized battlefield. These waveforms will need to be compatible with the Joint Tactical Radio System (JTRS) platforms being developed and as such will need to implemented in software. The waveform proposed herein is an advanced technology that has been matured under commercial development, and which has proved its capability to provide robust, high-efficiency communications in heavy interference and multipath environments. The waveform accomplishes this by a synergistic combination of several enabling technologies, namely packetized time-division duplex (TDD) networking protocols, stacked carrier spread spectrum (SCSS) modulation formats, fast Fourier transform (FFT) based discrete multitone (DMT/OFDM) modulation formats, adaptive antenna arrays, blind adaptive spatial and spectral despreading (receive combining) and spreading (transmit combining) algorithms, and trellis and turbo coding algorithms. The results of this Phase I program can provide a very high spectral efficiency, covert and jam-resistant waveform for hosting on the JTRS family of radios. The basic technique can also be used to greatly enhance the capacity of commercial wireless voice and data communications networks, cellular overlay networks, and burst-oriented wireless local-area networks and private branch exchanges, PCS/PCNs, and packet-data networks, where it can provide as much as 30-fold capacity over the existing GSM, D-AMPS (IS-54), CDMA (IS-95), and Cellular Digital Packet Data (CDPD) networks.
