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.

Spectrally Efficient CPM Waveforms for Narrowband Tactical Communications in Frequency Hopped Networks

Abstract: A family of spectrally efficient waveforms for serial concatenated continuous phase modulation in frequency hopping systems is presented, for the challenging case where there are multiple hops per interleaver duration. The proposed waveforms are designed for narrowband tactical communication systems and are shown to meet stringent spectral emission masks of -40 dBc at the band edges for terrestrial communications below 100 MHz whilst maintaining data rates up to 64 kbit/sec in a standard 25 kHz bandwidth. In addition, a design approach is outlined enabling near-constant envelope waveforms for a variety of user defined information rates. This ensures efficient use of energy by the transmitter power amplifier, and achieves good performance and spectral efficiency for both tactical data and low latency voice communications. Furthermore, simulation results based on channel measurements in the tactical VHF band allow for the evaluation of the overall system performance in typical multipath environments

Coherent Full-Duplex Double-Sided Two-Way Ranging and Velocity Measurement Between Separate Incoherent Radio Units

Abstract: This paper presents a novel coherent full-duplex (FD) double-sided two-way ranging (CFDDS-TWR) technique for wireless locating and velocity measurement between separate radio units. The idea presented here is a quantum leap in wireless locating since it enables coherent ranging, continuous phase tracking, and velocity measurement between wireless units that operate incoherently with separate low-cost crystal oscillator clock sources. Frequency modulated continuous wave chirp sequences are exchanged in a FD manner between two radio units. The signals transmitted from two radio units are received, respectively, by each of the two units and down-converted in a mixer with the receiver’s own transmit signal to generate a beat signal in each unit. The two beat signals are then processed together, after one beat signal is transmitted to the partner unit. Phase coherent range and Doppler phase measurements can be conducted between incoherent radio units. The presented CFDDS-TWR technique also offers options for reducing noise-like distortions caused by mixing the products of uncorrelated phase noise. We show both analytically and experimentally that the described compensation method reduces the noise level and enhances the dynamic range of the ranging signals tremendously—as evidenced by an improvement of around 24 dB in our results. These unique signal and synchronization properties show that the CFDDS-TWR method is a highly accurate measurement approach. Results acquired with a 24-GHz test system in a 7- to 17-m range demonstrate a standard deviation in range and velocity of 0.25 mm and 0.05 mm/s, respectively.

Space-time code design with CPM transmission

Abstract: Design criterion for space-time codes with continuous phase modulation (CPM) in a quasistatic fading channel is given. Space-time codes are proposed and simulation results demonstrate their good performance.

Tri-state integer cycle modulation

Abstract: The invention disclosed in this application uses a method of modulation named Tri-State Integer Cycle Modulation (TICM) wherein a carrier signal, comprised of a continuum of sine waves is modulated such that spectrum utilization is minimal. A modulation event is imposed upon the carrier signal by modifying the carrier frequency at precisely the zero crossing point or the zero degree angle. The method of imposing the modulation event is by increasing the frequency of the carrier for one or an integer number of wavelets then lowering the frequency of the carrier for one or the same integer number of wavelets then returning to the carrier frequncy to derive the modulation event. The main carrier frequency is only modulated beginning at the zero degree phase angle and ending at the 360-degree phase angle.

Low-power Tx module for high-resolution continuous programmable phase shift

Abstract: A novel phase shifter topology for digital phased antenna arrays based on a low-power phase control block joint with an innovative PLL design is presented. Experimental results obtained by a prototype are reported validating the architecture capabilities.