Communication Waveform Design Using an Adaptive Spectrally Modulated, Spectrally Encoded (SMSE) Framework

US Air Force Inst. of Technol., Wright-Patterson AFB, OH
IEEE Journal of Selected Topics in Signal Processing (Impact Factor: 3.3). 07/2007; DOI: 10.1109/JSTSP.2007.897061
Source: IEEE Xplore

ABSTRACT Fourth-generation (4G) communication systems will likely support multiple capabilities while providing universal, high-speed access. One potential enabler for these capabilities is software-defined radio (SDR). When controlled by cognitive radio (CR) principles, the required waveform diversity is achieved through a synergistic union called CR-based SDR. This paper introduces a general framework for analyzing, characterizing, and implementing spectrally modulated, spectrally encoded (SMSE) signals within CR-based SDR architectures. Given orthogonal frequency division multiplexing (OFDM) is one 4G candidate signal, OFDM-based signals are collectively classified as SMSE since data modulation and encoding are applied in the spectral domain. The proposed framework provides analytic commonality and unification of multiple SMSE signals. Framework applicability and flexibility is demonstrated for candidate 4G signals by: 1) showing that resultant analytic expressions are consistent with published results and 2) presenting representative modeling and simulation results to reinforce practical utility

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    ABSTRACT: A hybrid GA-RSM optimization process is introduced for Spectrally Modulated, Spectrally Encoded (SMSE) waveform design in a coexistent environment containing a Direct Sequence Spread Spectrum (DSSS) system. Expanding upon previous efforts that used independent GA and RSM techniques under perfect DSSS code tracking conditions, a hybrid GA-RSM optimization process is demonstrated here under more realistic conditions with imperfect DSSS code tracking. Two SMSE waveform parameters (number of carriers and carrier bandwidth) are optimized in a coexistent scenario to characterize SMSE impact on Direct Sequence Spread Spectrum (DSSS) bit error rate (Pb). Hybrid optimization for minimum DSSS Pb yields SMSE waveforms that were consistent with scenarios having no coexistent SMSE signal present (best-case coexistence). Optimization for maximum DSSS Pb yields worst-case SMSE-DSSS coexistence with resultant SMSE waveforms being spectrally ldquomatchedrdquo to the DSSS signal.
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    ABSTRACT: ABSTRACT Wireless communication,transmissions pack the airwaves, andgovernment
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    ABSTRACT: An experimental design approach is used to determine which factors (design parameters) of spectrally modulated, spectrally encoded (SMSE) waveforms have the greatest impact on coexistence with other communication waveforms. The SMSE framework supports cognition-based, software defined radio (SDR) applications and is well-suited for coexistence analysis. For initial proof-of-concept, a two factor (parameter), three-level (value) experimental design technique is applied to a coexistent scenario to characterize SMSE waveform impact on direct sequence spread spectrum (DSSS) receiver performance. The experimental design methodology reliably captures factor-level sensitivities and identifies those factors having greatest impact on system coexistence behavior (bit error variation). Given these initial results and its effectiveness in other engineering fields, it is believed that experimental design may pave the way for developing more rigorous waveform design methods and allow more robust coexistence analysis of conventional, DSSS and SMSE waveforms.
    Communications, 2007. ICC '07. IEEE International Conference on; 07/2007