SBIR-STTR Award

This project designs and demonstrates the feasibility of an innovative high performance low PAPR spectrally compliant communication waveform design for naval communication systems over multiple non-contiguous spectrum fragments via our unique polyphase non-contiguous carrier interferometry spreading spectrum technology. Novel spectrally coded (namely carrier interferometry code) waveforms are employed in non-contiguous OFDM technology to spread the information across available non-contiguous subcarriers. The spreading of the information over multiple subcarriers introduces frequency diversity and leads to higher BER performance in multi-path wireless channels. Furthermore, the information spreading equips the wireless network with anti-jamming capability. Additionally, the carefully chosen carrier interferometry code combines the benefits of single carrier transmission with multi-carrier transmission and provides much lower peak to average power ratio (PAPR) than that of current OFDM systems. Most importantly, by turning off the subcarriers which are not available due to spectrum availability or spectrum disturbance, and by adaptively reallocating the polyphase carrier interferometry spreading codes, the proposed wireless communication system provides the capability of operating over multiple non-contiguous spectrum fragments and maintaining the orthogonality among the spreading codes. As a direct result, our systems offer the best performance and throughput, as well as lowest PAPR, among all existing cognitive radio waveforms.

Benefit:
This innovative non-contiguous spectrally coded carrier interferometry spreading spectrum technology has great potential for both military and commercial applications. While the primary DoD application is for high performance military mobile networks, this technology can bring higher performance and higher throughput to current commercial wireless networks as well, and it will also be an important extension to current IEEE 802.16 and IEEE 802.22 standards.

Keywords:
Spread OFDM, Spread OFDM, Non-contiguous Spectrum, Cognitive Radio, Carrier Interferometry, PAPR, Spectrally Compliant Waveform, OFDM, spectrum fragmentation,

Built upon our prior efforts and existing industry/academia relationships, our research and development efforts in this Phase II will develop and commercialize an innovative high performance spectrally compliant waveform generator not only for communication waveforms but also for other naval RF applications such as radar, navigation and electronic warfare systems in complex and hostile environments. The developed system is an integration of novel spreading spectrum technology, cognitive radio technology, software defined radio technology, and cross layer design techniques. Our main objectives are: (1) Create an universal waveform generating platform to generate spectrally compliant cognitive RF waveforms for all RF applications operating over multiple non-contiguous spectrum fragments; (2) Develop an intelligent spectrum sensing engine which is capable of not only detecting the existence of RF transmissions and spectrum fragments but estimate the parameters of the RF transmissions and finally identify the signals; (3) Further improve the performance of RF applications by exploiting both unused spectrum holes and under-used spectrum bands; (4) Implement these complex algorithms for real-time applications using a software defined radio platform; (5) Commercialize the research and development results; and (6) (optional) extend the work to underwater acoustic signals to enhance the spectrum efficiency of underwater acoustic communication and sonar applications.

Benefit:
This technology has many non-military areas of application in addition to its obvious application to DoD customers and homeland security customers. Specifically, the novel waveform generation technology has the potential to significantly increase the spectrum efficiency of all RF applications in private sector such as cellular phone networks, wireless local/regional area networks, satellite networks, GPS navigation systems, and so on.

Keywords:
PAPR, Spread OFDM, spectrum fragmentation, Carrier Interferometry, OFDM, Cognitive Radio and intelligent spectrum sensing, Non-contiguous Spectrum, Spectrally Compliant Waveform and high performance cognitive RF