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.

Pilot-symbol aided continuous phase modulation system

Abstract: Apparatus for transmitting and receiving digital information over mobile communication channels. The apparatus includes a pilot symbol insertion device for periodically inserting data dependent pilot symbols into frames of digital data for subsequent channel estimation, a continuous phase modulator for modulating and transmitting over a mobile communication channel the frames of digital data and means for receiving and filtering the transmitted data. A channel estimator estimates the channel amplitude and phase distortion from the received pilot signal at different time instants. Means are provided for demodulating the received signal and for decoding the demodulated signal to recover the estimated transmitted data.

A High Spectral Efficiency Coherent Microwave Photonic Link Employing Both Amplitude and Phase Modulation With Digital Phase Noise Cancellation

Abstract: A high spectral efficiency coherent microwave photonic link (MPL) supporting amplitude and phase modulation incorporating a digital phase noise cancellation is proposed and experimentally demonstrated. At the transmitter, a continuous-wave light wave is amplitude- and phase-modulated by two microwave vector signals carried by a microwave carrier at an identical frequency. The modulated optical signal is polarization multiplexed with an unmodulated optical carrier and transmitted over a length of a single-mode fiber (SMF). At the receiver, the optical signal is detected coherently by a coherent receiver to which a local oscillator (LO) laser source is also applied. Through advanced digital signal processing, the microwave vector signals are recovered, and the phase noise introduced by both the transmitter laser source and LO laser source is cancelled. An experiment is performed. The transmission of a 2.5-Gb/s 16-QAM and a 1.25-Gb/s QPSK microwave vector signals both at 2.5 GHz over a 25-km SMF is implemented. The total bit rate of the MPL is 3.75 Gb/s. The transmission performance of the MPL in terms of error vector magnitudes and bit error rates is evaluated.

Noncoherent sequence detection receiver for Bluetooth systems

Abstract: The design of power efficient receivers for Bluetooth systems is a challenging task due to stringent complexity constraints. In this paper, we tackle this problem and present a receiver design consisting of a single filter and a subsequent noncoherent sequence detector. This receiver outperforms the conventional discriminator detector by more than 4 dB for typical Bluetooth channels. Thereby, the proposed noncoherent sequence detection (NSD) algorithm is both favorably low complex as it operates on a two-state trellis and highly robust against channel phase variations caused by low-cost local oscillators. The particular filter design accomplishes effective out-of-band interference suppression. Different from previous work on sequence detector receivers published in the literature, we take possible variations of the Bluetooth modulation parameters into account, and we also devise efficient methods for combined NSD and forward error correction decoding. Hence, the presented receiver design is an attractive solution for practical Bluetooth devices.

Low-complexity linear frequency domain equalization for continuous phase modulation

Abstract: In this paper, we develop a new low-complexity linear frequency domain equalization (FDE) approach for continuous phase modulated (CPM) signals. As a CPM signal is highly correlated, calculating a linear minimum mean square error (MMSE) channel equalizer requires the inversion of a nondiagonal matrix, even in the frequency domain. In order to regain the FDE advantage of reduced computational complexity, we show that this matrix can be approximated by a block-diagonal matrix without performance loss. Moreover, our MMSE equalizer can be simplified to a low-complexity zero-forcing equalizer. The proposed techniques can be applied to any CPM scheme. To support this theory we present a new polyphase matrix model, valid for any block-based CPM system. Simulation results in a 60 GHz environment show that our reduced-complexity MMSE equalizer significantly outperforms the state of the art linear MMSE receiver for large modulation indices, while it performs only slightly worse for small ones.

Serial MSK-Type Detection of Partial Response Continuous Phase Modulation

Abstract: Partial response continuous phase modulation (CPM) schemes have a high spectrum utilization and also a high immunity to nonlinear distortion, since they have a constant envelope. Schemes with high power efficiency can also be designed when they are coherently detected with a Viterbi detector. These schemes are sometimes complex, however. In this paper two minimum-shift-keyed (MSK)type receivers are studied. The MSK-type receiver can be implemented as a serial receiver and as a parallel receiver. Both receivers are useful for binary modulation schemes with modulation index h = 1/2 . Only coherent detection of signals transmitted over an additive white Gaussian noise channel is considered. The serial receiver can be implemented with only two filters and simple decision logic. The decisions are made serially in one decision eye pattern. Two types of receiver filters are considered. Error probability results are presented for the receiver, both with and without phase and timing errors present in the receiver. It is shown that, assuming perfect phase and time synchronization, the serial and parallel receivers have equal performances. The advantages of the serial receiver over the parallel receiver are the same for partial response continuous phase modulation as for classical MSK; i.e., both in implementation aspects and in the reduced sensitivity to phase errors.