Continuous phase modulation

About: Continuous phase modulation is a research topic. Over the lifetime, 3199 publications have been published within this topic receiving 37245 citations. The topic is also known as: CPM.

Satellite navigation receiver for precise relative positioning in real time

Abstract: A navigation receiver system provides real-time precise relative positioning in cooperation with an associated carrier phase receiver. The navigation receiver system and the associated carrier phase receiver both sample signals during a single epoch, and the associated carrier phase receiver processes the received signals to provide and transmit first carrier phase measurement data. The navigation receiver system comprises a data link receiver that receives the first carrier phase measurement data from the associated carrier phase receiver, and a carrier phase receiver that receives carrier phase signals during the sampling epoch, and processes the carrier phase signals to provide a second carrier phase measurement data. The navigation system receiver also includes a processing unit that receives the first carrier phase measurement data and the second carrier phase measurement data and computes carrier phase difference measurements. The processing unit applies a local-minima search technique to the carrier phase difference measurements to resolve carrier phase integer ambiguities within the subspace of local minima, wherein the resolved carrier phase integers are subsequently used to determine a precise relative position of the navigation receiver system with respect to the associated carrier phase receiver. The present invention provides high precision, real-time position data from a signal time epoch. That is, the present invention resolves the integer ambiguities in carrier phase measurements with a single snap shot of the measurements. In addition, the system recovers very quickly following a signal interruption.

Space-time code design for CPFSK modulation over frequency-nonselective fading channels

Abstract: We derive a novel space-time code (STC) design criterion for continuous-phase frequency-shift keying (CPFSK) over frequency-nonselective fading channels. Our derivation is based on a specific matrix that is related to the input symbols of the CPFSK modulators. With this code-design criterion, we propose a simple interleaved space-time encoding scheme for CPFSK modulation over frequency-nonselective correlated fading channels to exploit potential temporal and spatial diversity advantages. Such an encoding scheme consists of a ring convolutional encoder and a spatial encoder, between which a convolutional interleaver is placed. A decoding algorithm that generates symbol metrics for the Viterbi decoder of convolutional codes from the spatial modulation trellis is examined. Simulation results confirm that the advantages of the combination of the interleaved convolutional encoding (for temporal diversity) and the spatial encoding (for spatial diversity) are promising for various system parameters.

Techniques to generate constant envelope multicarrier transmission for wireless networks

Abstract: Various example embodiments are disclosed herein. According to an example embodiment, an apparatus for use in a wireless transmitter may include a continuous phase modulation (CPM) sample generator configured to generate a group of constant envelope CPM modulated signal samples, a Fourier transform block configured to perform a Fourier transform on the group of constant envelope signal samples to generate an initial group of Fourier coefficients, a zero insertion block configured to generate an expanded group of Fourier coefficients by inserting one or more zeros in the initial group of Fourier coefficients, and an inverse Fourier transform block configured to perform an inverse Fourier transform on the expanded group of Fourier coefficients to generate a group of constant envelope time-domain samples and to map the constant envelope time-domain samples onto a group of orthogonal subcarriers for transmission.

Sinusoidal phase-modulating interferometer with ellipse fitting and a correction method.

Abstract: In a sinusoidal phase-modulating interferometer, sinusoidal modulation of the phase of the laser or the reference wave is necessary. However, modulation of the phase also involves an intensity modulation of the light, which leads to a measurement error if conventional signal processing is used. In addition, the error of modulation depth and the phase delay of demodulation also increase the measurement error. A novel signal processing, with ellipse fitting and a correction method, is proposed. Numerical simulation results and experimental results prove that the novel signal processing can compensate for the measurement error caused by the intensity modulation, the error of modulation depth, and the phase delay of demodulation.

Transmitter-in-the-loop optimization of distorted OFDM radar emissions

Abstract: The inherent amplitude modulation of orthogonal frequency division multiplexing (OFDM) has limited its use in radar due to transmitter-induced distortion. Specifically, there is a necessary trade-off between reduced SNR caused by power back-off to accommodate these AM effects and the waveform distortion that occurs when driving the amplifier closer to saturation. Here a method is developed to design OFDM-based radar emissions with low range sidelobes in the presence of transmitter-induced distortion. This work builds upon previous results for hardware-in-the-loop optimization of continuous phase modulation (CPM) waveforms to demonstrate how saturated OFDM emissions may potentially provide a feasible alternative waveform design scheme.