• COMPARISON OF RECEIVERS FOR MULTI-H CPM

      Rice, Michael; Perrins, Erik; Brigham Young University (International Foundation for Telemetering, 2002-10)
      A noncoherent receiver for the general case of M-ary partial response multi-h continuous phase modulation (CPM) is presented. The receiver operates on the principle of sequence estimation via the Viterbi Algorithm (VA). It offers a significant complexity reduction from the optimal coherent maximum likelihood sequence estimating (MLSE) receiver. The performance of the receiver is evaluated with computer simulations. It performs at a loss of 1–6 dB relative to the MLSE receiver for the CPM schemes considered in the simulations. The receiver shows promise in applications requiring reduced complexity and use of existing hardware.
    • ON THE PERFORMANCE OF MULTI-H CPM IN MULTIPATH INTERFERENCE

      Rice, Michael; Perrins, Erik; Brigham Young University (International Foundation for Telemetering, 2002-10)
      The performance of multi-h CPM over multipath interference channels is evaluated with computer simulations using the optimal coherent receiver and a suboptimal noncoherent receiver. For channels with high-amplitude short-delay multipath reflections, the simulations show that both receivers reach an error floor in their performance as the amplitude of the multipath reflections grows. The rate of degradation for the noncoherent receiver is worse than for the coherent receiver. For channels with low-amplitude long-delay reflections the coherent and noncoherent receivers had losses of 1 dB and 3 dB respectively relative to their respective unfaded performance.
    • A WIDEBAND CHANNEL MODEL FOR AERONAUTICAL TELEMETRY — PART 1: GEOMETRIC CONSIDERATIONS AND EXPERIMENTAL CONFIGURATION

      Rice, Michael; Davis, Adam; Bettwieser, Christian; Brigham Young University (International Foundation for Telemetering, 2002-10)
      This paper is the first of two papers that present a multipath channel model for wideband aeronautical telemetry. Channel sounding data, collected at Edwards AFB, California at both L-Band and lower S-Band, were used to generate channel model. In Part 1, analytic and geometric considerations are discussed and the frequency domain modeling technique is introduced. In Part 2, the experimental results are summarized and a channel model composed of three propagation paths is proposed.
    • A WIDEBAND CHANNEL MODEL FOR AERONAUTICAL TELEMETRY — PART 2: MODELING RESULTS

      Rice, Michael; Davis, Adam; Bettwieser, Christian; Brigham Young University (International Foundation for Telemetering, 2002-10)
      This paper is the second of two papers that present a multipath channel model for wideband aeronautical telemetry. Channel sounding data were collected at Edwards AFB, California at both L-Band and lower S-Band. Frequency domain analysis techniques were used to evaluate candidate channel models. The channel model is composed of three propagation paths: a line-of-sight path, and two specular reflections. The first specular reflection is characterized by a relative amplitude of 70% to 96% of the line-of-sight amplitude and and a delay of 10 – 80 ns. This path is the result of “ground bounces” off the dry lake bed at Edwards and is a typical terrain feature at DoD test ranges located in the Western USA. The amplitude and delay of this path are defined completely by the flight path geometry. The second path is a much lower amplitude path with a longer delay. The gain of this path is well modeled as a zero-mean complex Gaussian random variable. The relative amplitude is on the order of 2% to 8% of the line-of-sight amplitude. The mean excess delay is 155 ns with an RMS delay spread of 74 ns.