Gaussian Minimum Shift Keying Research Articles

Ultra reliability and massive connectivity provision in integrated internet of military things (IoMT) based on tactical datalink

One of the major challenges arising in internet of military things (IoMT) is accommodating massive connectivity while providing guaranteed quality of service (QoS) in terms of ultra-high reliability. In this regard, this paper presents a class of code-domain nonorthogonal multiple accesses (NOMAs) for uplink ultra reliable networking of massive IoMT based on tactical datalink such as Link-16 and joint tactical information distribution system (JTIDS). In the considered scenario, a satellite equipped with Nr antennas servers K devices including vehicles, drones, ships, sensors, handset radios, etc. Nonorthogonal coded modulation, a special form of multiple input multiple output (MIMO)-NOMA is proposed. The discussion starts with evaluating the output signal to interference-plus-noise (SINR) of receiver filter, leading to the unveiling of a closed-form expression for overloading systems as the number of users is significantly larger than the number of devices admitted such that massive connectivity is rendered. The expression allows for the development of simple yet successful interference suppression based on power allocation and phase shaping techniques that maximizes the sum rate since it is equivalent to fixed-point programming as can be proved. The proposed design is exemplified by nonlinear modulation schemes such as minimum shift keying (MSK) and Gaussian MSK (GMSK), two pivotal modulation formats in IoMT standards such as Link-16 and JITDS. Numerical results show that near capacity performance is offered. Fortunately, the performance is obtained using simple forward error corrections (FECs) of higher coding rate than existing schemes do, while the transmit power is reduced by 6 dB. The proposed design finds wide applications not only in IoMT but also in deep space communications, where ultra reliability and massive connectivity is a keen concern.

PERFORMANCE ANALYSIS OF GMSK-BASED COOPERATIVE COMMUNICATION IN WIRELESS SENSOR NETWORKS

An efficacious energy model based on Gaussian minimum shift keying (GMSK) for cooperative communication is proposed in this paper. The influence of the rate at which data are transmitted, distance, severity of fading, and quantity of participating nodes on the energy expended for communication by the proposed model is investigated through simulations. The influence of the rate at which data are transmitted and the quantity of participating nodes on the energy expended in circuitry is also studied. Through the simulations, it is apparent that the energy consumed by the circuit dominates the energy consumed for transmission for all of the transmission data rates, path loss exponents, bit error rates, and transmission distances considered.

GMSK Demodulation Combining 1D‐CNN and Bi‐LSTM Network Over Strong Solar Wind Turbulence Channel

AbstractTo solve the problem of bit error rate (BER) performance degradation over strong solar wind turbulence channel, this paper addresses to Gaussian minimum frequency shift keying (GMSK) demodulation using machine learning. First, by analyzing the scintillation characteristics of the telemetry signal caused by solar wind turbulence during the solar superior conjunction, the K distribution channel model is innovatively established over strong solar wind turbulence channel. Then, the approximate probability density function of the K distribution of the established channel is studied by using Laguerre orthogonal polynomial for convenience. Additionally, the BER performance of GMSK over strong solar wind turbulence channel is analyzed. Second, using a one‐dimensional convolutional neural network (1D‐CNN) and bidirectional long short‐term memory network (Bi‐LSTM), two demodulators for GMSK are proposed. By integrating the 1D‐CNN and LSTM to extract local features and process the dynamic information of GMSK signals, we propose a novel GMSK demodulator over strong solar wind turbulence channel with combining 1D‐CNN and Bi‐LSTM. The simulation results show that, even if the solar wind turbulence has serious effects on the signal at a low signal‐to‐noise ratio, the proposed combining neural network demodulation can obtain better BER performance than the classical Viterbi algorithm, demodulation using only a single 1D‐CNN or Bi‐LSTM. The proposed GMSK demodulator is more suitable for the deep space exploration of the solar system.

Waveform design and signal processing method for integrated underwater detection and communication system

AbstractFor the integrated system of underwater detection and communication, an emitted waveform should satisfy both detection and communication requirements. The signal processing method at the receiving end must also accomplish target detection and communication accordingly. This study uses a generalised sinusoidal frequency modulated (GSFM) waveform with a carrier to ensure detection performance. At the same time, the communication information encoding with Gaussian Minimum Shift Keying is modulated to the GSFM signal for communication purposes. Unlike previous work, an improved Blind Source Separation algorithm is utilised at the receiving end, which is better adapted to waveform separation and processing in the underwater time‐varying unknown environment. The analysis of detection probability, peak‐to‐average ratio, and signal processing results show that the proposed waveform and corresponding signal processing scheme can effectively meet the need for integrated underwater detection and communication system.

UOWC performance based on GMSK modulation

Abstract This paper studies and investigates the performance of Gaussian minimum shift keying (GMSK) for underwater optical wireless communication (UOWC). Various scatterings may result in inter-symbol interference (ISI) and degrade system error performance in UWOC links. Bit-error rate (BER) is evaluated using different water environment models such as clear seawater, coastal, and harbor for a 20 m link range. Simulation results indicate the BER performance is degraded due to the temporal dispersion of impulse response for high data rates in turbid water. In addition, the bandwidth-symbol time product (BT) is an essential parameter in GMSK, affecting BER performance and power efficiency. Therefore, BT must be chosen with a value that balances BER and power efficiency. The results show that GMSK with BT = 0.5 is a good choice that satisfies BER = 10−5 for SNR = 10 dB with an efficient power spectrum due to constant envelope and low out-of-band radiation.

Design of a Robust Orthogonal Frequency Division Multiplexing (OFDM) Transceiver for a Cognitive Radio Testbed

Primarily, a Cognitive Radio (CR) resolves the problem of spectrum scarcity and underutilization. However, it should also attain a good throughput and Quality of Service (QoS) as its objectives. These requirements are solely dependent on the modulation used. Though single carrier modulations such as Gaussian Minimum Shift Keying (GMSK) are highly spectral efficient, they are not robust to frequency selective fading. An implementation of multicarrier modulation supports high spectral efficiency and resistance to multipath fading. Therefore, in this paper, there is a comprehensive how-to-guide of the design of Orthogonal Frequency Division Multiplexing (OFDM) in cognitive radio using GNU Radio (GR) 3.8 that interfaces with Universal Software Radio Peripheral (USRP) B210s for video transmission. The implementation achieved allows for the choice of any modulation schemes out of four commonly used ones for communication of the payloads thus offering dynamism for use in a cognitive radio system. The effective implementation of the proposed methods in this paper is verified by the successful transmission and reception of a 4 minute 37 seconds MP4 video across the different choices of modulation schemes. It was observed that the error performance of the payloads degraded with higher constellation points however, the throughput was increased. Hence, the trade-off between error probability and throughput in the cognitive radio is based on the radio-scene metrics about the signal-to-noise ratio (SNR) of the available channels.

A GMSK/PAM4 Multichannel Magnetic Human Body Communication Transceiver

This letter presents a dual-mode multichannel transceiver implemented with low path loss offered by magnetic human body communication (mHBC) toward ultraefficient body-area networking. Two spectral-efficient modulation schemes: 1) Gaussian minimum-shift keying (GMSK) and 2) 4-level pulse-amplitude modulation (PAM4), are used to reduce interference on adjacent channels. A power oscillator is used to efficiently generate both GMSK- and PAM4-modulated magnetic fields while multichannel selection is implemented by on-chip capacitor tuning and an analog PLL, enabling 5 and 10 Mb/s data for GMSK and PAM4, respectively. The transmitter achieves an efficiency of 15.5 and 19.4 pJ/bit, while the receiver consumes 4.6 and 2.7 pJ/bit for GMSK and PAM4, respectively.

A new ABER approximation of FSO system using PPM–GMSK hybrid modulation scheme under weak turbulence

In this paper, free space optical communication system (FSO) employing a hybrid modulation technique called pulse position modulation–Gaussian minimum shift keying (PPM–GMSK) technique, is investigated by considering log–normal as the channel fading statistics under weak turbulence. The analytical average bit error rate (ABER) and closed form expression of the proposed hybrid modulation scheme are derived. Simulation results depict the excellent agreement of the derived closed form expression with those obtained using Gauss–Hermite approximation and with the Monte Carlo simulations.

Design of Software-Defined Radio-Based Adaptable Packet Communication System for Small Satellites

Software-defined radio (SDR) devices have made a massive contribution to communication systems by reducing the cost and development time for radio frequency (RF) designs. SDRs opened the gate to programmers and enabled them to increase the capabilities of these easily manipulated systems. The next step is to upgrade the reconfigurability into adaptability, which is the focus of this paper. This research contributes to improving SDR-based systems by designing an adaptable packet communication transmitter and receiver that can utilize the communication window of CubeSats and small satellites. According to the feedback from the receiver, the transmitter modifies the characteristics of the signal. Theoretically, the system can adopt many modes, but for simplicity and to prove the concept, here, the changes are limited to three data rates of the Gaussian minimum shift keying (GMSK) modulation scheme, i.e., 2400 bps GMSK, 4800 bps GMSK and 9600 bps GMSK, which are the most popular in amateur small satellites. The system program was developed using GNU Radio Companion (GRC) software and Python scripts. With the help of GRC software, the design was simulated and its behavior in simulated conditions observed. The transmitter packetizes the data into AX.25 packets and transmits them in patches. Between these patches, it sends signaling packets. The patch size is preselected. Alternatively, the receiver extracts the data and saves it in a dedicated file. It directly replies with a feedback message whenever it gets the signaling packets. Based on the content of the feedback message, the characteristics of the transmitted signal are altered. The packet rate and the actual useful data rate are measured and compared with the selected data rate, and the packet success rate of the system operating at a fixed data rate is also measured while simulating channel noise to achieve the desired Signal-to-Noise Ratio (SNR).

Performance vs. Spectral Properties for Single-Sideband Continuous Phase Modulation

This study revokes the performance of continuous phase modulation (CPM) able to generate a single-sideband (SSB) spectrum directly. This signal is analyzed in terms of modulation indices, pulse lengths, and pulse widths, all of which affect error probability, bandwidth, SSB property, and receiver complexity. The error probability performance is based on an approximation of the minimum Euclidean distance. A numerical power spectral density calculation for this particular SSB modulation in terms of the modulation index is presented. Reasonable tradeoffs in designing modulation schemes have been proposed using multi-objective optimization to ensure sizable improvements in bit error rate (BER), spectral efficiencies, and complexity without losing the property of being a SSB signal. Performance comparisons are made with known CPM schemes, e.g., Gaussian Minimum Shift Keying (GMSK) and Raised Cosine based CPM (RC).

Performance Enhancement of Gaussian Minimum Shift Keying Using Optimum Phase Sampling Technique for Turbulent Free-Space Optical Communication

In this paper, analytical performances of Gaussian minimum shift keying (GMSK) are studied for free space optical communication system. Authors propose an innovative sampling technique called, optimum phase sampling technique to investigate the bit error performance of GMSK modulation. Subsequently, performances of GMSK like, bit error rate (BER), power spectral density, and adjacent carrier interference (ACI) have also been investigated and compared with other modulation techniques. Furthermore, return to zero (RZ) coding input bit stream prior to GMSK technique improves the ACI performance of GMSK. To end with, we present the improvement of degradation parameter (γ) in a tabular form through phase sampling technique. Moreover, both optimum phase sampling and narrow pulse shaping of RZ-GMSK obtains near optimal result of BER. The numerical results show, that the proposed phase sampled RZ-GMSK of 70% duty cycle at BT = 0.6 has a degradation value of 0.979, which is comparable to GMSK at BT = ∞. Moreover, the proposed RZ-GMSK achieves lower ACI value and has an error rate of 7 × 10−7, which is lower than the GMSK of 1 × 10−6 BER value.

Design and analysis of optimized CORDIC based GMSK system on FPGA platform

The Gaussian minimum shift keying (GMSK) is one of the best suited digital modulation schemes in the global system for mobile communication (GSM) because of its constant envelop and spectral efficiency characteristics. Most of the conventional GMSK approaches failed to balance the digital modulation with efficient usage of spectrum. In this article, the hardware architecture of the optimized CORDIC-based GMSK system is designed, which includes GMSK Modulation with the channel and GMSK Demodulation. The modulation consists of non-return zero (NRZ) encoder, an integrator followed by Gaussian filtering and frequency modulation (FM). The GMSK demodulation consists of FM demodulator, followed by differentiation and NRZ decoder. The FM Modulation and demodulation use the optimized CORDIC model for an In-phase (I) and quadrature (Q) phase generation. The optimized CORDIC is designed by using quadrant mapping and pipelined structure to improve the hardware and computational complexity in GMSK systems. The GMSK system is designed on the Xilinx platform and implemented on Artix-7 and Spartan-3EFPGA. The hardware constraints like area, power, and timing utilization are summarized. The comparison of the optimized CORDIC model with similar CORDIC approaches is tabulated with improvements.

Detection of Malicious Primary User Emulation Based on a Support Vector Machine for a Mobile Cognitive Radio Network Using Software-Defined Radio

Mobile cognitive radio networks provide a new platform to implement and adapt wireless cellular communications, increasing the use of the electromagnetic spectrum by using it when the primary user is not using it and providing cellular service to secondary users. In these networks, there exist vulnerabilities that can be exploited, such as the malicious primary user emulation (PUE), which tries to imitate the primary user signal to make the cognitive network release the used channel, causing a denial of service to secondary users. We propose a support vector machine (SVM) technique, which classifies if the received signal is a primary user or a malicious primary user emulation signal by using the signal-to-noise ratio (SNR) and Rényi entropy of the energy signal as an input to the SVM. This model improves the detection of the malicious attacker presence in low SNR without the need for a threshold calculation, which can lead to false detection results, especially in orthogonal frequency division multiplexing (OFDM) where the threshold is more difficult to estimate because the signal limit values are very close in low SNR. It is implemented on a software-defined radio (SDR) testbed to emulate the environment of mobile system modulations, such as Gaussian minimum shift keying (GMSK) and OFDM. The SVM made a previous learning process to allow the SVM system to recognize the signal behavior of a primary user in modulations such as GMSK and OFDM and the SNR value, and then the received test signal is analyzed in real-time to decide if a malicious PUE is present. The results show that our solution increases the detection probability compared to traditional techniques such as energy or cyclostationary detection in low SNR values, and it detects malicious PUE signal in MCRN.

Rényi Entropy-Based Spectrum Sensing in Mobile Cognitive Radio Networks Using Software Defined Radio.

A very important task in Mobile Cognitive Radio Networks (MCRN) is to ensure that the system releases a given frequency when a Primary User (PU) is present, by maintaining the principle to not interfere with its activity within a cognitive radio system. Afterwards, a cognitive protocol must be set in order to change to another frequency channel that is available or shut down the service if there are no free channels to be found. The system must sense the frequency spectrum constantly through the energy detection method which is the most commonly used. However, this analysis takes place in the time domain and signals cannot be easily identified due to changes in modulation, power and distance from mobile users. The proposed system works with Gaussian Minimum Shift Keying (GMSK) and Orthogonal Frequency Division Multiplexing (OFDM) for systems from Global System for Mobile Communication (GSM) to 5G systems, the signals are analyzed in the frequency domain and the Rényi-Entropy method is used as a tool to distinguish the noise and the PU signal without prior knowledge of its features. The main contribution of this research is that uses a Software Defined Radio (SDR) system to implement a MCRN in order to measure the behavior of Primary and Secondary signals in both time and frequency using GNURadio and OpenBTS as software tools to allow a phone call service between two Secondary Users (SU). This allows to extract experimental results that are compared with simulations and theory using Rényi-entropy to detect signals from SU in GMSK and OFDM systems. It is concluded that the Rényi-Entropy detector has a higher performance than the conventional energy detector in the Additive White Gaussian Noise (AWGN) and Rayleigh channels. The system increases the detection probability (PD) to over 96% with a Signal to Noise Ratio (SNR) of 10dB and starting 5 dB below energy sensing levels.

Joint Viterbi detection and decoding algorithm for bluetooth low energy systems

An efficient joint Viterbi detection and decoding (JVDD) algorithm for a bluetooth low energy (BLE) system is proposed. Since the convolutional coded Gaussian minimum-shift keying (GMSK) signal is specified in the BLE 5.0 standard, two Viterbi processors are needed for detection and decoding. However, the proposed JVDD scheme uses only one Viterbi processor by modifying the branch metric with inter-symbol interference information from GMSK modulation; therefore, the hardware complexity can be significantly reduced without performance degradation.

Performance Realization of CORDIC based GMSK System with FPGA Prototyping

The Gaussian Minimum Shift Keying (GMSK) modulation is a digital modulation scheme using frequency shift keying with no phase discontinuities, and it provides higher spectral efficiency in radio communication systems. In this article, the cost-effective hardware architecture of the GMSK system is designed using pipelined CORDIC and optimized CORDIC models. The GMSK systems mainly consist of the NRZ encoder, Integrator, Gaussian filter followed by FM Modulator using CORDIC models and Digital Frequency Synthesizer (DFS) for IQ Modulation in transmitter section along with channel, the receiver section has FM demodulator, followed by Differentiator and NRZ decoder. TheCORDIC algorithms play a crucial role in GMSK systems for IQ generation and improve the system performance on a single chip. Both the pipelined CORDIC and optimized CORDIC models are designed for 6-stages. The optimized CORDIC model is designed using quadrature mapping method along with pipeline structure. The GMSK systems are implemented on Artix-7 FPGA with FPGA prototyping. The Performance analysis is represented in terms of hardware constraints like area, time and power. These results show that the optimized CORDIC based GMSK system is a better option than the pipelined CORDIC based GMSK systems for real-time scenarios.

PAPR Reduction of OFDM Signal Through DFT Precoding and GMSK Pulse Shaping in Indoor VLC

Optical orthogonal-frequency-division-multiplexing (O-OFDM) has been widely explored for visible light communication (VLC) to achieve high data rates. However, O-OFDM suffers from high peak-to-average power ratio (PAPR), which causes clipping distortion, reduces illumination to communication conversion efficiency and affects the lifetime of the light-emitting diode (LED). This paper proposes a novel modulation technique, an amalgamation of discrete Fourier transform (DFT) precoding and Gaussian minimum shift keying (GMSK) pulse shaping to reduce the PAPR of OFDM based VLC system. Furthermore, the concept of group precoding is also introduced to deal with the increased complexity of the DFT precoding system. The results show that different variants of the proposed scheme provide improved PAPR, symbol-error-rate (SER), and power-saving performance as compared to the corresponding DFT precoded O-OFDM and O-OFDM counterpart. Moreover, the analytical study of PAPR, computational complexity and spectral efficiency for the proposed system have also been investigated and reported in this paper.

Research on the system performance of Gaussian minimum-shift keying with M-distribution in satellite-to-ground laser communication

In this paper, a Gaussian minimum shift keying (GMSK) modulation based on M-distribution is proposed for uplink satellite-to-ground laser communication systems. Considering the noise caused jointly by intensity scintillation, beam wander and angle of arrival (AOA) fluctuations in the satellite-to-ground laser uplink communication, the closed-form expression of bit error rate (BER) of GMSK modulation system is derived. The system performance under weak, medium and strong turbulence is studied. The relationship between signal-to-noise ratio and BER is analyzed using simulations, and compared with the differential phase shift keying modulation currently used in the satellite-to-ground laser communication systems. Furthermore, the effects of zenith angle, receiver aperture, transmitter beam radius and divergence angle on the system performance are studied. This research work provides guidance for system performance analysis of uplink satellite-to-ground laser communication.

Performance of Smart Grid Dynamic HAN With RQAM and GMSK Modulation

In smart grid communications, home area network (HAN) plays an important role in managing data transmission among communicating devices through a smart meter. Performance of the network depends on the efficiency of modulation schemes used in the communicating devices such as rectangular quadrature amplitude modulation (RQAM) and Gaussian minimum shift keying (GMSK). Saleh-Valenzuela (S-V) and Weibull fading channels are appropriate models for indoor communication channels. Average symbol error rate (ASER) and average channel capacity (ACC) performance of indoor dynamic HANs with communicating devices using RQAM and GMSK are analyzed for these channel models. Numerical results are presented to demonstrate the effect of traffic intensity, number of active devices in HAN, and the modulation types with parameters of practical interest.

An Improved Adaptive Modulation and Coding for Cross Layer Design in Wireless Networks

Recent research in cross layer design focuses on a number of integration techniques with physical layer to maintain a strategic distance from the shortcomings of Open Systems Interconnect (OSI) layer and also to guarantee the Quality of Service (QoS) in heterogeneous systems. Amongst the integration techniques, the Rate-Adaptive Modulation and Coding draws more attention of the researchers. In this paper, an improved Adaptive Modulation and Coding (AMC) scheme for Cross layer approach has been proposed with slight modifications in the existing AMC scheme that considerably improves the spectral efficiency of the transmission framework for time varying channels. The existing AMC conspire uses the well-known modulation techniques like Binary Phase Shift Keying, Quadrature Phase Shift Keying and Quadrature Amplitude Modulation with different rates that yield low spectral efficiency. This paper presents an improved AMC with the Gaussian Minimum Shift Keying (GMSK) modulation that yields a spectral efficiency of 35% more than the traditional AMC. Proposed method also results in a maximum throughput of 20–50% more than the traditional AMC. The evaluation of performance metrics like Signal to Noise ratio and error rate clearly depicts that the proposed approach significantly outperforms the traditional AMC.