• Adjacent Channel Interference for Turbo-Coded APSK

      Rice, Michael; Shaw, Christopher; Brigham Young University (International Foundation for Telemetering, 2008-10)
      A study of the effects of interference caused by adjacent channels on the performance of turbo-coded 16- and 32-APSK. Included in our discussion is the spectral regrowth in the nonlinear power amplifier when driven by a non-constant envelope modulation. Ultimately, we present a set of channel spacing guidelines when using turbo-coded APSK for aeronautical telemetry.
    • Iterative Equalization for SOQPSK in Multipath Fading

      Lei, Qiang; Rice, Michael; Brigham Young University (International Foundation for Telemetering, 2008-10)
      This paper investigates the application of iterative equalization techniques to overcome multipath fading for shaped offset QPSK (SOQPSK) in aeronautical telemetry. Two iterative equalization techniques for turbo encoded SOQPSK are presented. The first is the optimal-MAP turbo equalizer for OQPSK. The second equalizer is the adaptive decision feedback equalizer. Simulation shows that in the presence of frequency selective multipath typically encountered in aeronautical telemetry, both of these equalizers exhibit impressive performance.
    • Space-Time Shaped Offset QPSK

      Rice, Michael; Dang, Xiaoyu; Brigham Young University (International Foundation for Telemetering, 2008-10)
      This paper describes the use of orthogonal space-time block codes to overcome the performance and complexity difficulties associated with the use of Shaped Offset QPSK (SOQPSK) modulation, a ternary continuous phase modulation (CPM), in multiple-input multiple-output telemetry systems. The orthogonal space-time block code is applied to SOQPSK waveforms in the same way it would be applied to symbols. The procedure allows the receiver to orthogonalize the link. The main benefits of this orthogonalization are the easy realization of the transmit diversity for the offset-featured SQOSPK, and the removal of the noise correlation at the input to the space-time decoder and the elimination of I/Q interference when space time orthogonalization is applied to the symbol level.