Minimum Shift Keying Modulation Research Articles

A new derivation of the Nakagami-m distribution as a composite of the Rayleigh distribution

AbstractMobile communications systems are affected by what is known as fading, which is a well-known problem largely studied for decades. The direct consequence of fading is the complete loss of signal (or a large decrease of the received power). Rayleigh fading is a reasonable model for wireless channels although, Nakagami-m distribution seems better suited to fitting experimental data. In this paper we obtain the Nakagami-m distribution as a composite (mixture) of the Rayleigh distribution, a result which as far as we know it has not been shown in the literature. This representation of the Nakagami-m distribution facilitates computations of the average BER (Bit Error Rate) for DPSK (Differential Phase Shift Keying) and MSK (Minimum-Shift Keying) modulations for this distribution and higher moments of them, which is of great applicability to modeling wireless fading channels. Furthermore, a simple, not depending on any special function, apart of the Gamma function, bivariate version of the Nakagami-m distribution is also proposed as a special case of the multivariate version which is also presented. The proposed composite distribution is simulated through the standard procedure of summation of phasors, and results for the new closed-form measures for the MSK modulation are also shown. From that it is clear that the alternative formulation of the Nakagami-m distribution allows for easier modeling of fading fading-shadowing wireless channels through the new explicit second order statistics metrics. is well suited for modelling fading-shadowing wireless channels.

A tactical data link model based on CCSK-FMSK

In collaborative combat operations, the challenges brought by the communication adversities of tactical data links are becoming increasingly prominent. Ensuring the reliable connection of tactical data links has always been a key issue, especially considering the increasing impact of external interference on the signal at the receiving end of the system, which in turn affects the bit error rate (BER) of the tactical data link system. To address this challenge, this paper proposes a tactical data link anti-interference scheme based on cyclic code shift keying (CCSK) spread spectrum and minimum shift keying (MSK) modulation fusion frequency hopping technology, named CCSK-FMSK, and introduces turbo code and cyclic redundancy check (CRC) coding to construct a tactical data link model based on CCSK-FMSK. Specifically, CCSK-FMSK disperses interference power by expanding the signal spectrum, enhancing the anti-interference ability of tactical data links. CRC coding and Turbo coding achieve error detection and correction by introducing supervised symbols. In addition, this paper proposes a soft despreading and a soft demodulation algorithm corresponding to CCSK spread spectrum and MSK modulation to achieve cascade with Turbo decoder and improve the error rate performance and robustness of the model. Compared with existing models, the tactical data link based on CCSK-FMSK has better BER performance.

Blind Modulation Classification for Asynchronous OFDM Systems Over Unknown Signal Parameters and Channel Statistics

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. However, till date, only a few works have been reported in the literature for blind MC of orthogonal frequency division multiplexing (OFDM) system over frequency-selective fading environment. In this paper, a blind MC algorithm has been proposed and implemented over National Instruments (NI) testbed setup for linearly modulated signals of OFDM system by using discrete Fourier transform (DFT) and normalized fourth-order cumulant. The proposed MC algorithm works in the presence of synchronization errors, i.e., frequency, timing, and phase offsets and without the prior information about the signal parameters and channel statistics. To nullify the effect of timing offset in the feature extraction process, a statistical average has been taken over OFDM symbols after introducing uniformly distributed random timing offsets in each of the OFDM symbols. In this work, we have classified a more extensive pool of modulation formats for OFDM signal, i.e., binary phase-shift keying (BPSK), quadrature PSK (QPSK), offset QPSK (OQPSK), minimum shift keying (MSK), and 16 quadrature amplitude modulation (16-QAM). Classification is performed in two stages. At the first stage, a normalized fourth-order cumulant is used on the DFT of the received OFDM signal to classify OQPSK, MSK, and 16-QAM modulation formats. At the second stage, first we compute the DFT of the square of the received OFDM signal and then a normalized fourth-order cumulant is used to classify BPSK and QPSK modulation formats. The success rate of the proposed MC algorithm is evaluated through analytical and Monte Carlo simulations and compared with existing methods. Finally, the work is validated by providing an experimental setup on NI hardware over an indoor propagation environment.

Research on MSK Demodulation Method for M-Sequence in IFF System

M-Sequence, short for Maximum Linear Feedback Shift Register Sequence, is widely used in identification friend or foe (IFF) system because of its good equalization and autocorrelation characteristics, and Minimum Shift Keying (MSK) signal has been paid more attention in military communication field because of its excellent signal characteristics. A new demodulation method for MSK modulation signal of M-Sequence is studied. The MSK signal is sampled by A/D converter, and an integration circuit is designed in the FPGA. The same M-Sequence is generated by the same M-Sequence source polynomial as the integrator coefficient. The peak value of the integrated signal is judged to determine the M-Sequence. When the symbol rate is 1 Mbps and the carrier rate is 1 Mbps and M-Sequence is 5 bits, the recognition time of the new method is less than 1 us, which is less than one fifth of the recognition time of the traditional demodulation method. This method simplifies the demodulation process and is easy to implement. It improves the recognition speed of M-Sequence in MSK modulation signal and provides some reference value for the development of IFF system.

CDF and MGF based analysis over Rayleigh TWDP shadowed fading channel for indoor communication

ABSTRACTRecently, the two-wave with diffuse power (TWDP) distribution has been extensively used to model the shadowing in multipath-faded/shadowed indoor environment. In this article, novel expressions for joint moments, mean, second moment, variance and cumulative distribution function for Rayleigh TWDP shadowed fading model are derived. By using the derived expression of mean and variance, the expression for amount of fading is obtained. Also, the outage probability, moment generating function and average bit error rate (ABER) for various modulation schemes namely binary phase shift keying (BPSK), binary frequency shift keying (BFSK), minimum shift keying (MSK), differentially coherent phase shift keying (DCPSK) and non-coherent frequency shift keying (NCFSK) are calculated. The derived expressions for cumulative distribution function, outage probability and ABER are presented in analytical format and have been numerically evaluated. Moreover, the numerical results of ABER using MSK and DPSK modulation schemes is compare with results of Rayleigh Gamma composite fading model. The study shows that better outage probability (0.01) is observed at 40dB average signal to noise ratio (SNR) with 5dB lowest threshold SNR, however, at higher threshold SNR (>5dB) with fixed average SNR (40dB), poor outage probability performance are obtained. Further, at higher shadowing (10dB), for fixed average SNR (15dB), minimum error probability (10−4) is observe, while at lower shadowing (less than 10dB), higher error probability (greater than 10−4) is observed that represents poor BER performance.

Research on the system performance evaluation of minimum-shift keying in uplink ground-to-satellite with gamma–gamma distribution

Minimum-shift keying (MSK) has the advantages of constant envelope, continuous phase, and high spectral efficiency, and it is applied in radio communication and optical fiber communication. MSK modulation of coherent detection is proposed in the ground-to-satellite laser communication system; in addition, considering the inherent noise of uplink, such as intensity scintillation and beam wander, the communication performance of the MSK modulation system with coherent detection is studied in the uplink ground-to-satellite laser. Based on the gamma–gamma channel model, the closed form of bit error rate (BER) of MSK modulation with coherent detection is derived. In weak, medium, and strong turbulence, the BER performance of the MSK modulation system is simulated and analyzed. To meet the requirements of the ground-to-satellite coherent MSK system to optimize the parameters and configuration of the transmitter and receiver, the influence of the beam divergence angle, the zenith angle, the transmitter beam radius, and the receiver diameter are studied.

Impact of reformed RM Encoded data on PAPR of Multicode CDMA under MSK

In this research work, the effect of ReformedReed Muller Encoded Data (RRMED) on Peak to Average PowerRatio (PAPR) of Multicode Code Division Multiple Access(MC-CDMA) systems was studied under Minimum Shift Keying(MSK) modulation. Simulation studies revealed thatimplementation of RRMED on PAPR with MSK modulation cansave up to 7dB of transmitter power compared to the un-codedPAPR of MC-CDMA systems.Simulation results further proved that MSK modulation alsoplays an important role in reducing PAPR as compared to binaryPhase Shift Keying (PSK).

4 Impact of reformed RM Encoded data on PAPR of Multicode CDMA under MSK

In this research work, the effect of ReformedReed Muller Encoded Data (RRMED) on Peak to Average PowerRatio (PAPR) of Multicode Code Division Multiple Access(MC-CDMA) systems was studied under Minimum Shift Keying(MSK) modulation. Simulation studies revealed thatimplementation of RRMED on PAPR with MSK modulation cansave up to 7dB of transmitter power compared to the un-codedPAPR of MC-CDMA systems.Simulation results further proved that MSK modulation alsoplays an important role in reducing PAPR as compared to binaryPhase Shift Keying (PSK).

Impact of reformed RM Encoded data on PAPR of Multicode CDMA under MSK

In this research work, the effect of ReformedReed Muller Encoded Data (RRMED) on Peak to Average PowerRatio (PAPR) of Multicode Code Division Multiple Access(MC-CDMA) systems was studied under Minimum Shift Keying(MSK) modulation. Simulation studies revealed thatimplementation of RRMED on PAPR with MSK modulation cansave up to 7dB of transmitter power compared to the un-codedPAPR of MC-CDMA systems.Simulation results further proved that MSK modulation alsoplays an important role in reducing PAPR as compared to binaryPhase Shift Keying (PSK).

Design of Novel MSK Architectures using R-F Bit

In this paper, we present two novel reformulations (1) and (20) for MSK (Minimum Shift Keying) modulation technique. By using these novel reformulations, we find an additional switching bit, referred to as R-F bit, and propose a novel MSK architecture. Compared to known prior MSK architectures, our architecture offers significant advantages with respect to power consumption and hardware efficiency. Additionally, a pre-computation technique is used to reduce ram bit utilization (RBU) of the proposed modulator. Considering the whole modulation procedure, this approach reduces the RBU of the proposed architecture by 75%. The experimental results show that our architecture is very suitable for MSK modulation. DOI: http://dx.doi.org/10.5755/j01.eie.22.3.15322

Based on Simulink the MSK Communication System Design and Research

Minimum shift keying (MSK) signal is constant envelope modulation technology, It has the characteristics of continuous phase, high frequency band utilization, is very attractive in the field of wireless communications digital modulation mode, the current in short wave, microwave and satellite communications have been adopted. This paper studies the working principle of MSK modulation and demodulation, and then build simulation module based on Simulink environment, through the simulation design to render the MSK system performance advantages.

Properties, performance and practical interest of the widely linear MMSE beamformer for nonrectilinear signals

Widely Linear (WL) Minimum Mean Square Error (MMSE) estimation has received a great interest these last 20 years for second order (SO) noncircular signals. In the context of radio communications networks, it has been shown in particular that WL MMSE receivers allow to implement Single Antenna Interference Cancellation (SAIC) of one rectilinear interference, such as Binary Phase Shift Keying (BPSK) or Amplitude Shift Keying (ASK) interference, or of quasi-rectilinear interference, such as Minimum Shift keying (MSK), Gaussian MSK (GMSK) or Offset Quadrature Amplitude Modulation (OQAM) interference, hence their great interest for Global System for Mobile Communications (GSM) cellular networks in particular. However, one may wonder whether WL MMSE receivers remain attractive for SO noncircular nonrectilinear interferences, not so scarce in practice. The purpose of this paper is mainly to answer to this important question by giving, in a self-contained and unified way, some new insights into the behavior, properties and performance of the WL MMSE beamformer in the presence of arbitrary noncircular signals and interference which are not necessarily rectilinear. It is shown in particular that, surprisingly, WL MMSE receivers lose their practical interest for strong interferences which are not rectilinear. This breakthrough thus generates a new open problem for the choice between linear and WL MMSE receiver corresponding to the detection of rectilinearity (and/or quasi-rectilinearity), instead of noncircularity, in a given noisy observation. Although this question is out of the scope of this paper, we finally propose preliminary tools based on blind source separation methods to solve this problem.

Resonant Tunneling Diode Optoelectronic Circuits Applications in Radio-Over-Fiber Networks

Phase-locked oscillators based on resonant tunneling diodes are used in this study to implement transceiver components that perform conversion between optical and wireless phase shift-keyed signals using injection-locked oscillator techniques. Three different links are demonstrated at frequencies of 940 MHz, 1.3 GHz, and 3.2 GHz that are capable of locking to a phase-modulated signal that propagates from the optical to the wireless and back to the optical domains. The transmitter and receiver are evaluated through Gaussian minimum shift-keying modulation accuracy metrics. Deployment of the transceiver in radio-over-fiber architectures is also discussed.

Studying and comparing spectrum efficiency and error probability in GMSK and DBPSK modulation schemes

Gaussian minimum shift keying (GMSK) and differential binary phase shift keying (DBPSK) are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc). Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift ke-ying) modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error pro-bability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when re-covering a signal.

Linear and nonlinear distortion effects in direct detection 40 Gb/s MSK modulation formats multi-span optically amplified transmission

The generation of minimum shift keying (MSK) requires a linear variation of the phase, hence a constant frequency of the optical carrier. However, the generation of the optical phase may be preferred by driving an optical modulator using sinusoidal signal for practical implementation. Thus a nonlinear variation of the carrier phase, hence some distortion effects are produced. In this paper, we investigate the use of linear and nonlinear phase shaping filtering and their impacts on MSK modulated optical signals transmission over optically amplified long haul communications system. The evolution of the phasor of the in-phase and quadrature components is illustrated for lightwave-modulated signal transmission. The distinct features of three different MSK modulation formats: linear MSK, weakly nonlinear MSK and strongly nonlinear MSK and their transmission are simulated. Transmission performance obtained indicates the resilience of the MSK signals in transmission over multi-optically amplified multi-spans.

New insights into optimal widely linear array receivers for the demodulation of BPSK, MSK, and GMSK signals corrupted by noncircular interferences-application to SAIC

For nonstationary observations, potentially second-order (SO) noncircular, the SO optimal complex filters are time variant and, under some conditions of noncircularity, widely linear (WL). For more than a decade, there has been an increasing interest in optimal WL filters in radiocommunications contexts involving rectilinear signals such as binary phase-shift keying (BPSK) signals. In particular, it has been pointed out that single antenna interference cancellation (SAIC) may be performed by such filters in the context of BPSK cellular networks. Recently, it has been shown that, by a simple algebraic operation of demodulation on the baseband signal, the minimum shift keying (MSK) and Gaussian MSK (GMSK) modulations can be made to approximately correspond to a BPSK modulation, allowing the application of the SAIC concept to the GSM cellular network at the mobile level, being currently studied for standardization, and offering significant improvements of the network's capacity. Despite the increasing interest in optimal WL filters in rectilinear or quasi-rectilinear contexts, many questions about their behavior and their performance have still arisen. The purpose of this paper is to gain insight into the behavior, properties, and performance of optimal WL array receivers, and thus of the SAIC technology, for the demodulation of BPSK, MSK, and GMSK signals corrupted by noncircular interferences.

Design and analysis of feedforward symbol timing estimators based on the conditional maximum likelihood principle

This paper presents a general feedforward symbol-timing estimation framework based on the conditional maximum likelihood principle. The proposed timing estimator presents reduced implementation complexity and is obtained by performing an approximation on the Fourier series expansion of the conditional maximum likelihood function. The proposed algorithm is applied to linear modulations and two commonly used continuous phase modulations: minimum shift keying (MSK) and Gaussian MSK (GMSK). For the linear modulations, it is shown both analytically and via simulations that the performance of the proposed estimator is very close to the conditional CRB and modified CRB for signal-to-noise ratios (SNRs) in the range SNR /spl les/ 30 dB. Furthermore, the proposed estimator is shown to be asymptotically equivalent to the classic square-law nonlinearity estimator under certain conditions. In the case of MSK and GMSK modulations, although the proposed algorithm reaches the conditional CRB at certain SNRs, however, the conditional CRB is quite far away from the modified CRB, and there exists an alternative algorithm whose performance comes closer to the modified CRB. Therefore, the proposed estimator is more suitable for linear modulations than for MSK and GMSK modulations.

A Preliminary Study to Assess Possible Chromosomal Damage Among Users of Digital Mobile Phones

In a preliminary study to examine possible lymphocyte chromosomal damage, we have tested two cytogenetic endpoints, namely, chromosomal aberrations (CA) and sister chromatid exchange frequencies (SCE), in 24 mobile phone users (12 nonsmoker–nonalcoholic subjects and 12 smoker–alcoholics), who used digital mobile phones for at least 2 years, employing Gaussian Minimum Shift Keying modulations with uplink frequencies at 935–960 MHz. and downlinks at 890–915 MHz. For comparison, the control study group included another 24 individuals, matched according to their age, sex, drinking and smoking habits, as well as similar health status, working habits, and professional careers; but did not use mobile phones. Blood samples of 12 mobile users (6 smoker–alcoholic and 6 nonsmoker–nonalcoholic) and 12 controls (identical to mobile users in every respect) were further treated with a known mutagen Mitomycin‐C (MMC) to find out comutagenic/synergistic effect. A complete blood picture for each individual was assessed with an automatic particle cell counter.There was a significant increase (P < 0.05) in dicentric chromosomes among mobile users who were smoker–alcoholic as compared to nonsmoker–nonalcoholic; the same held true for controls of both types. After MMC treatment, there was a significant increase in dicentrics (P < 0.05) and ring chromosomes (P < 0.001) in both smoker–alcoholic and nonsmoker–nonalcoholic mobile users when compared with the controls. Although SCEs showed a significant increase among mobile users, no change in cell cycle progression was noted. The hematological picture showed only minor variations between mobile users and controls.

The effects of filtering and nonlinear amplification on the performance of DS-CDMA with OQPSK-type modulations

This paper investigates the effects of channel filtering and nonlinear amplification on the signal-to-noise ratio (SNR) performance of direct-sequence code-division multiple-access systems employing offset quadrature modulation formats with various chip waveforms. An average SNR analysis is developed and followed by numerical examples to illustrate relative performance merits among modulation formats, including offset quaternary phase-shift keying (OQPSK), minimum shift keying (MSK), sinusoidal frequency shift keying (SFSK), and time-domain raised-cosine shaped QPSK (TDRC). The channel filtering considered is based on Butterworth-type filters with varying 3-dB cutoff bandwidth, and the nonlinear amplification is modeled by amplitude hard limiting. The results obtained show little SNR performance differences between the cases of filtering alone and combined filtering and hard limiting. It is also found that for tighter filtering (one-sided 3-dB bandwidth on the order of half the chip rate), all modulations have comparable performance, but that for wider filter bandwidth values, differences become more noticeable, with SFSK and TDRC slightly better than MSK (on the order of 0.5 dB) and clearly outperforming OQPSK (by up to 1.5 dB). On the other hand, examples with strictly bandlimited signals employing frequency-domain Nyquist raised cosine (FDRC) filtering with a rolloff factor varying from zero to one showed a clear degradation in performance (by about 1 dB) due to the introduction of hard limiting. These schemes were also outperformed by all of OQPSK, MSK, SFSK, and TDRC modulations when combined with strict brick wall filtering, with SNR differences ranging from 1 to 2 dB.

Serial concatenated coding scheme with minimum shift keying

A novel serially concatenated coding scheme for use with minimum shift keying (MSK) is proposed. The novelty is to use a mixture of recursive and non-recursive realisations for the MSK modulator. It is shown that this improves the performance of iterative demodulation and decoding of convolutionally encoded MSK signals with a slight decrease in the decoder complexity.