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.

Optical phase multi-value modulation method, optical phase multi-value modulating device, and error control method

Abstract: PROBLEM TO BE SOLVED: To provide an optical phase multi-value modulation method of simpler configuration and an optical phase multi-value modulation device, and an error control method using the same. SOLUTION: When a ϕ degree is defined as a phase value and (n) as ≥3 and an integer below the number of phase shift modulators in the method for phase modulation of the laser beam from a laser beam source with a plurality of the phase modulators arranged in series, the phase modulation of 0° or 2ϕ° is performed in the first phase modulator and the phase modulation of 0° or 2 2 ϕ° is performed in the second phase modulator and generally, the phase modulation of 0° or 2 n ϕ° is performed in the n-th phase modulator. Also, the error detection or error control of each one bit is performed by making modulation and transmission with the same signals in the two modulators, receiving and decoding the signals on a reception side and confirming that their codes are the same. COPYRIGHT: (C)2004,JPO

Bit Erro r Rate Analysis in Simulation of Digital Communication Systems with Different Modulation Schemes

Abstract: With the increasing demand in communication, it has become necessary to give better and efficient service to users by using better technique. This paper analyse the bit error rate, for different modulation schemes such as Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK. By Choosing a reliable modulation scheme and better coding technique the enhancement of the performance can be obtained in transmitter and receiver of the system. Simulated result is shown to analyse and compare the performance of these systems by using additive white Gaussian noise channel (AWGN). Finally the different modulation schemes are compared on the basis of BER and best modulation scheme is determined. From analysis of two modulation techniques, the system could use more appropriate modulation technique to suit the channel quality, thus we can deliver the optimum and efficient system parameters. LabVIEW has been used for simulation.

Optimised phase disposition (PD) modulation of a modular multilevel converter using a state machine decoder

Abstract: This paper presents a theoretical harmonic analysis of phase disposition (PD) and phase shifted carrier (PSC) pulse width modulation (PWM) strategies for MMC converters. It is shown that when these strategies are implemented on a per MMC arm basis, their spectral performances converge because of cancellation of odd carrier sideband groups between each phase leg's arms. An improved PD modulation strategy is then presented that uses a single PD modulator for the entire phase leg, followed by a state machine decoder that evenly distributes switching pulses to all sub-modules across the phase leg upper and lower arms to balance the distribution of sub-module commutation events. The resulting strategy achieves optimum phase leg PD spectral performance, and also achieves natural voltage balancing of the MMC sub-modules. All theoretical findings are supported by simulation and experimental results obtained using a five level MMC prototype.

An EM Algorithm for Path Delay and Complex Gain Estimation of Slowly Varying Fading Channel for CPM Signals

Abstract: This paper addresses the joint path delay and time-varying complex gain estimation for continuous phase modulation (CPM) over a time-selective slowly varying flat Rayleigh fading channel. We propose an expectation-maximization (EM) algorithm for path delay estimation in a Kalman smoother framework. The time-varying complex gain is modeled by a first order autoregressive (AR) process. Such a modeling yields to the representation of the problem by a dynamic bayesian system in a state-space form that allows the application of EM algorithm in the context of unobserved data for obtaining an estimate of the path delay. This is used with Kalman smoother for state estimation. We derive analytically a closed-form expression of the modified hybrid Cramer-Rao bound (MHCRB) for path delay and complex gain parameters. Finally, some numerical examples are presented to illustrate the performance of the proposed algorithm compared to the conventional generalized correlation method and to the MHCRB.

A reduced complexity iterative non-coherent CPM detector for frequency hopped wireless military communication systems

Abstract: An iterative symbol-by-symbol non-coherent detection scheme using serially concatenated continuous phase modulation for application in wireless, frequency hopping, military communication systems is presented. The scheme exploits an iterative tree search algorithm in the detector, to reduce the overall complexity of the receiver, whilst maintaining a BER performance within 0.5 dB compared to detectors employing exhaustive tree search techniques. In addition, simulation results show that the iterative detection scheme can readily be employed to enable reliable communications in the presence of signal jamming and/or interference in frequency hopping systems