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.

System for demodulation of phase-shift keying signals

Abstract: in a system for demodulation of phase shift keying signals with a bandpass filter (6a) adapted to regenerate a carrier wave from a phase shift keying signal, there are provided means (8) for detecting phase variations in the regenerated carrier wave from the demodulated signal (e 1 , e 2 ), and means (8, 6a) for controlling the phase of the carrier wave being passed through the filter (6a) on the basis of the detection output (e c ) of the phase variation detecting means (8).

Discrete continuous-phase superresolving filters

Abstract: A new type of phase-only superresolving pupil filter with a discrete continuous-phase profile is presented that is a combination of discrete multilevel-phase modulation and continuous-phase modulation. This type of filter can achieve better superresolution performance than the continuous-phase filters reported in Opt. Lett.28, 607 (2003). Therefore, with regard to the superresolution effect, this type of filter deserves study for practical applications. More importantly, the diffraction performance of this type of filter can explain the effect of a discrete-phase filter illuminated with a continuous wave front, whose superresolving performance cannot be analyzed with previous superresolution methods.

Simple detectors for shaped-offset QPSK using the PAM decomposition

Abstract: In this paper we develop a reduced-complexity detection scheme for shaped-offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient constant-envelope modulation. The detector is based on the well-known pulse amplitude modulation (PAM) representation of continuous phase modulation (CPM). Since SOQPSK is a ternary CPM, we show how the binary-based PAM technique is extended to accommodate the ternary case. We demonstrate that a detector based on the first two PAM components requires a simple trellis of only 4 states. We show that near-optimum performance is achieved using this reduced-complexity detector. The potential complexity reduction can be quite large, since one version of SOQPSK requires a trellis of 512 states.

Pilot-Aided Trellis-Based Demodulation

Abstract: In optical transmission systems based on high-order modulations, the impact on system performance of Wiener phase noise affecting the received carrier phase can be relevant. To make less severe phase noise effects, solutions based on the use of known pilot symbols, that aid carrier phase recovery, have been recently introduced. This letter proposes a pilot-aided demodulation scheme where the memory of phase noise is dealt with by a trellis-based demodulation algorithm. The benefits in terms of achievable information rate and bit error rate compared to adversary schemes are demonstrated by computer simulations for strong phase noise with 4-ary quadrature amplitude modulation (4-QAM) and 16-QAM.

Data-aided linear prediction receiver for coherent DPSK and CPM transmitted over Rayleigh flat-fading channels

Abstract: In this paper, a new data-aided linear prediction receiver for coherent differentially encoded phase-shift keying (DPSK) and coherent continuous phase modulation (CPM) over Rayleigh flat-fading channels is presented, This receiver uses the previously detected symbols to estimate the carrier-phase reference and predict the channel gain continuously and therefore makes the optimal coherent detection of DPSK and CPM. The receiver has a simple structure and can be implemented easily. This is due partly to the fact that the linear predictors used for channel estimation do not depend on the autocorrelation function of the fading process. Simulation results on the bit error performance of QDPSK and minimum-shift keying (MSK) with the new receiver are given for both the additive white Gaussian noise (AWGN) and the Rayleigh flat-fading channels. The results show that the proposed receiver provides almost the same bit error rate (BER) performance as the ideal coherent receiver in an AWGN channel, is very robust against large carrier frequency offset between transmitter and receiver, and can provide a reasonably good BER performance in a fast Rayleigh fading channel. Finally, a multisample receiver is discussed and its error rate performance is evaluated by means of computer simulations. The results show that the multisample receiver provides good BER performance for higher fading rate.