M-ary Position Phase Shift Keying Research Articles

M-ary Phase Position Shift Keying Demodulation Using Stacked Denoising Sparse Autoencoders

A deep-learning based detector for M-ary phase position shift keying (MPPSK) systems is proposed in this paper. The major components of this detector include a special impact filter, a stacked denoising sparse autoencoder (DSAE), which was trained in unsupervised learning to extract features from the modulation signals, and a softmax classifier. The features learned by the stacked DSAE were then used to train the softmax classifier to demodulate the received signals into M classes. The architecture presented herein was trained and tested on a simple dataset extended by adding Gaussian noise only. The results from the theoretical analysis and simulation show that the detection performance of the proposed scheme is superior to that of existing detectors.

Anti-Multipath Performance Improvement of an M-ary Position Phase Shift Keying Modulation System.

Low-Power Wide-Area Network (LPWAN) is the technology that the Internet-of-Things (IoT) uses in long-distance, wide-coverage scenarios. As one of the ultra-narrowband (UNB) modulation techniques, M-ary position phase shift keying (MPPSK) modulation can provide high coverage and high reliability for LPWAN. This paper proposes a multipath separation method based on MPPSK modulation, which aims to eliminate the influence of multipath on the main path without increasing the spectrum overhead and system complexity. Specifically, the modulation parameter of the system is adjusted according to the delay value, so that the phase jump of the multipath signal falls outside the phase jump of the main path symbol to achieve separation of the multipath from the main path. Moreover, a normalized symbol joint decision method is proposed in order to reduce the introduced noise while using multipath information for decisions. The simulation results indicate that the multipath separation conditions given in this paper can meet the requirements of multipath separation of MPPSK signals. Compared with the existing mainstream decision scheme, the normalized symbol joint decision improves the demodulation performance of the system.

Adaptive Waveform Design for MIMO Radar-Communication Transceiver.

The system architecture for an adaptive multiple input multiple output (MIMO) radar-communication transceiver is proposed. A waveform design approach for communication data embedding into MIMO radar pulse using M-ary position phase shift keying (MPPSK) waveforms is introduced. A waveform optimization algorithm for the adaptive system is presented. The algorithm aims to improve the target detection performance by maximizing the relative entropy (RE) between the distributions under existence and absence of the target, and minimizing the mutual information (MI) between the current received signals and the estimated signals in the next time instant. The proposed system adapts its MPPSK modulated inter-pulse duration to suit the time-varying environment. With subsequent iterations of the algorithm, simulation results show an improvement in target impulse response (TIR) estimation and target detection probability. Meanwhile, the system is able to transmit data of several Mbps with low symbol error rates.

Non-orthogonal multi-carrier MIMO communication system using M-ary efficient modulation

In this paper, a wireless communication problem in Rayleigh fading channel is considered. A novel M-ary multi-carrier communication system is proposed to improve the communication performance, where both efficient modulation method and multi-input multi-output (MIMO) technique are combined. By using the time-hopping M-ary phase position shift keying (TH-MPPSK) in the multi-carrier MIMO system, we proposed two corresponding demodulation methods, including the one-by-one detection (OBD) and the improved OBD (IOBD), with low computational complexity. Additionally, we also propose a channel equalization method for the multi-carrier MIMO system. Simulation results demonstrate the effectiveness of the proposed efficient modulation and demodulation methods for MIMO systems with non-orthogonal multi-carrier signals.

An anti-noise modem for visible light communication systems using the improved M-ary position phase shift keying

In this paper, we propose an anti-noise modem based on the improved M-ary position phase shift keying (MPPSK) for visible light communication (VLC) systems. The line spectral interferences in the original MPPSK are theoretically analyzed and approximately mitigated by adopting a set of improved waveform samples. Then, within one symbol duration, the peak envelopes of the received signals are captured at each of synchronization bit with a quantity of sampling offsets to improve the proportion of the reliable data tones. In addition, a novel demodulation scheme using an amplitude-position detector based on soft decision is proposed to recover the MPPSK symbols, which can minimize the contamination influence of channel noise on symbol decision. With this scheme, the false alarm error and wrong slot error caused by the multipath fading in VLC channel can be effectively corrected and the bit error rate (BER) performance of the system is significantly improved. Simulation results demonstrate that the proposed scheme reduce the required signal-to-noise ratio (SNR) at least by 2 dB for BER = 10−4, which show the feasibility and validity of this anti-noise modem.

Neural Network-Based Receiver in Band-Limited Communication System with MPPSK Modulation

As a type of the spectrally efficient modulation, the m-ary phase position shift keying (MPPSK) has been considered to meet the increasing spectrum requirement in the future wireless system. To limit the signal bandwidth and cancel the out-band interference the band-pass filters are used, which introduce the waveform distortion and inter-symbol interference (ISI). Therefore, a single hidden-layer neural network (NN)-based receiver is proposed to jointly equalize and demodulate the received signal. The impulse response of the system is static and the network parameters can be obtained after off-line training. The number of the hidden nodes is also determined through simulations. Simulation results show that the NN-based receiver works well in the communication system with different allocated bandwidths. By observing the modified confusion matrix, the false symbol decision is relevant to modulation index, waveform distortions and the ISI.

Efficient modulation and demodulation methods for multi‐carrier communication

The modulation and demodulation problems for efficient multi-carrier communications are considered in this study. To maintain compact spectrum and realise dense multi-carrier transmission, a novel modulation method based on random hopping position, namely time hopping m-ary phase position shift keying (TH-MPPSK), is proposed to remove the discrete spectrum. Then, a multi-carrier scheme without guard interval among subcarriers is provided to reduce complexity in the practical communication systems. Moreover, a novel demodulation method is proposed to improve the efficient communication performance. Simulation results demonstrate that the TH-MPPSK can significantly remove the discrete spectrum and the proposed demodulation method can satisfactory performance.

M‐ary phase position shift keying with orthogonal signalling

An improved M-ary phase position shift keying (MPPSK) modulation, aiming to increase the spectral and energy efficiencies of existing MPPSK schemes while preserving their low demodulation complexity and error performance, is proposed in this study. Specifically, an improved MPPSK with orthogonal signals called OI-MPPSK is presented. For the proposed OI-MPPSK, the authors develop two demodulation schemes that employ a special impact filter (SIF): (i) the orthogonal SIF correlator (OSC) scheme, which consists of the orthogonal transmission, the SIF and a correlator; (ii) the orthogonal SIF position (OSP) scheme, which is the same as the OSC scheme except that the coherent demodulator is replaced by exploiting position-related information. As a result of exploiting the position-related information in the proposed OI-MPPSK scheme, the SER performance of the OSP-based demodulator is superior to that of the OSC-based demodulator.

改进的MPPSK调制的功率谱和解调性能

为改善多元位置相移键控(MPPSK)的解调性能，提出一种改进的MPPSK调制方案并推导出其功率谱表达式，与实际功率谱的对比验证了该理论表达式的正确。分析了不同调制参数与新调制方式对功率谱的影响。仿真结果表明改进MPPSK的调制信号与原MPPSK信号的功率谱和频谱利用率基本一致，但解调性能显著更优。 An improved M-ary phase position shift keying (MPPSK) modulation is introduced to enhance the demodulation abilities. The power spectra density (PSD) is derived, and its correctness is verified by comparing it with the practical PSD in simulation experiment. The influence of various para-meters and the improved modulation itself on PSD is analyzed. Simulation results demonstrate that the Bit Error Rate (BER) performance of this improved MPPSK modulation is much superior to its original version while its PSD and spectrum efficiency keeps almost unchanged.

A novel modulation scheme for short range polymer optical fiber communications

To make use of the spectrum of a step-index polymer optical fiber (SI-POF) channel, a hybrid modulation scheme is proposed combining discrete multi-tone modulation and M-ary position phase shift keying. The discrete line spectrum interference and sideband interference components of the new modulation scheme are analyzed. The waveform optimization factor and a new numerical symbol generating approach are introduced to strengthen the anti-interference capability of the system. Offline processing with an arbitrary waveform generator and digital storage oscilloscope is used to investigate the transmission performance. A transmission rate of 510.5 Mbps is achieved for a 50 m SI-POF in an intensity modulated direct detection system using eye-safe resonant cavity light-emitting diodes and a PIN diode at red 650 nm. The experimental verification demonstrates that, using the new methodology, an additional bit rate of 19.5 Mbps in the low signal-to-noise ratio region is obtained. Furthermore there 6 dB power is saved at a bit error rate (BER) of 1×10−4, so better spectral efficiency can be achieved. It is demonstrated that the proposed scheme can offer better BER performance and make a better compromise between transmission rate, power consumption, spectral efficiency and BER.

Composite Broadcasting and Ranging via a Satellite Dual-Frequency MPPSK System

Since digital video broadcasting via satellite (DVB-S) signals are “inefficient”, regarding the amount of information they convey on the bandwidth they occupy, a joint broadcasting and ranging system would constitute a unique platform for future digital video broadcasting satellite services effecting the essential tasks of satellite navigation system and direct to home (DTH) services, in terms of both spectrum efficiency and cost effectiveness. In this paper, the design of dual frequency M-ary position phase shift keying (MPPSK) system which is suitable for, respectively, performing both data transmission and range measurement is proposed. The approach is based on MPPSK modulation waveforms utilized in digital video broadcasting. In particular, requirements that allow for employing such signals for range measurements with high accuracy and high range are investigated. Also, the relationship between the frequency difference of dual frequency MPPSK system and range accuracy is discussed. Moreover, the selection of MPPSK modulation parameter for data rate and ranging is considered. In addition to theoretical considerations, the paper presents system simulations and measurement results of new systems, demonstrating the high spectral utilization of integrated broadcasting and ranging applications.

PLL demodulation technique for M-ray Position Phase Shift Keying

The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying (MPPSK) to send data and Phase Locked Loop (PLL) based techniques for data retrieve. With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization. Firstly, MPPSK modulation method is briefly introduced. 2PPSK’s PSD expression is given with its optimization result. Orthogonal Phase Detector (PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation. The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper. Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate (SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions. And finally, it is demonstrated by system simulations that lower than 10−4 Symbol Error Rate (SER) performance can be obtained at 13 dB symbol SNR.