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The increasing use of shared, unlicensed spectrum bands by medical devices and nonmedical products highlights the need to address wireless coexistence to ensure medical device safety and effectiveness. This paper provides the first step to approximate the probability of a device coexisting in its intended environment by providing a generalized framework for modeling the environment. The application of this framework is shown through an 84-day spectrum survey of the 2.4–2.48 GHz industrial, scientific, and medical band in a hospital environment in the United States. A custom platform was used to monitor power flux spectral density and record received power. Channel utilization of three nonoverlapping channels of 20 MHz bandwidth—relative to IEEE 802.11 channels 1, 6, and 11—were calculated and fitted to a generalized extreme value distribution. Low channel utilization was observed ( $ <$10%) in the surveyed environment with sporadic occurrences of higher channel utilization ($ >$ 50%). Reported findings can be complementary to wireless coexistence testing. This paper can provide input to the development of a consensus standard for wireless device coexistence test methods and a consensus document focused on wireless medical device coexistence risk management. [ABSTRACT FROM PUBLISHER]

In cellular communications certain frequency bands are licensed to specific applications guaranteeing predictability and reliability of service quality. Undesirable interference from these bands have to be removed by high-quality passive filters. This paper introduces a novel measurement method to determine the frequency response of a cellular system related to these passive filters. The method is based on in situ BER measurements and does not require access to the components of the transceiver hardware or knowledge about components and implementation. It is nondestructive and can be applied as in situ measurement of any wireless modem during normal operation. The results are successfully verified against direct S-parameter measurements of the SMT components. [ABSTRACT FROM PUBLISHER]

Conventional analytical and numerical approaches are inefficient for the analysis of electromagnetic (EM) coupling effect on a printed circuit board (PCB) in complicated electric systems. This paper develops a hybrid method based on the combination of electromagnetic topology and analytical method or full-wave simulation. A coupling mechanism of PCB in a nested shielding enclosure is established, and the EM interactions from exterior fields to interior PCB are determined by the way of conductive and radiation coupling interference. The total load disturbance voltage of PCB trace is obtained by solving the BLT equation of the two interference paths. In this paper, the full-wave simulation method is adopted to calculate the electric field and numerical integration method is applied to solve the BLT equation. The results of the proposed method are in good agreement with the result of a commercial full-wave tool, which confirms its validity. Compared to numerical simulation, the proposed method simplifies the modeling process significantly and possesses better efficiency. [ABSTRACT FROM PUBLISHER]

As electronic products become more and more complicated, multiple noise sources very likely interfere with the radio frequency receiver simultaneously. This paper proposes a method to identify the interference from different noise sources separately, even when they are radiating at the same time. This method converts magnetic fields to electric fields by the finite-element method (FEM) and employs the decomposition method based on reciprocity theory. In the proposed method, Huygens's surface will be set up for each source. The tangential magnetic near fields on each Huygens's surface are used to solve tangential electric fields correspondingly by the FEM. Then, the sources are removed but their Huygens's surfaces are kept. The victim structure is excited in this case to get the tangential magnetic fields on Huygens's surfaces. A creative FEM processing procedure is applied to obtain tangential electric fields in this situation. Finally, with these two groups of fields, the interference from each noise source can be estimated separately based on reciprocity theory. This method is validated by a numerical example. It is very helpful for engineers to be able to identify the contribution of the coupling from different sources and further solve the electromagnetic interference issues efficiently. [ABSTRACT FROM AUTHOR]

There are two cases that can cause cable overvoltage in a high-speed electric multiple units (EMU) system: one is the seriously rusty rail; the other is pantograph arcing, especially when the train passes through the phase separations. Both cases can endanger the normal operation of the EMU. In this paper, a full analysis is given on the mechanism of the electromagnetic interference, corresponding to the conducted and radiated interference. First, the actual circumstances in which the two kinds of interferences generate are described and the equivalent circuit model is established. Then, the two kinds of interference are analyzed and the induced overvoltage is calculated by means of finite-difference time domain method and piecewise-line technique. Next, based on the analysis mentioned above, a specific transient voltage suppressor (TVS) is proposed to be applied at the terminal of a cable in the train. Finally, the results of theoretical calculation, simulation by Computer Simulation Technology, and measurement are obtained and compared, among which a good agreement is achieved. Thus, the validity of the equivalent circuit model and the suppression effect of the TVS on overvoltage excited by conducted and radiated interference are verified. [ABSTRACT FROM AUTHOR]

This paper concerns a new approach for the characterization of power-line electromagnetic interference/radio-frequency interference (EMI/RFI) filters in a general impedance environment and continues to broaden the scope of one of previously published works. Specifically, the paper focuses on analyzing the lowest possible insertion loss of three-wire, single-phase EMI/RFI power-line filters in their stop-band at high megahertz or gigahertz frequencies. In contrast to the published work, the presented approach takes into account the reflections of converted modes at the filter input and output ports. A commercial single-phase EMI/RFI filter is analyzed in the frequency range of 1 to 10 GHz, in terms of common mode, differential mode and their conversions, by using the measured S-parameters of the filter and subsequently processing the obtained data. The results show that due to the reflections of conversion modes back into the structure of the filter, insertion loss values can be more than 20 dB lower than the results achieved by the previous known methods. [ABSTRACT FROM PUBLISHER]

In this paper, we present a methodology to characterize the I/O pins of a logic IC such as an application processor or ASIC with respect to soft-failure susceptibility due to electrostatic discharge. With the IC in a functional system, variable stress pulses are injected while the interface under test operates in real-world use cases. This test methodology enables the extraction of the IC behavior during ESD-like stress on a pin-by-pin basis. This characterization is intended to be performed during the validation stages of component development, making it possible to provide system developers with valuable information about potential modes of failure. This early detection of potential soft errors and their sensitivities can then be used to design for soft-failure robustness from the very beginning of system hardware and software design. [ABSTRACT FROM AUTHOR]

Remote keyless-entry systems are systems that are widely used to control access to vehicles or buildings. The system is increasingly secured against hacking attacks by use of encryption and code algorithms. However, there are effective hacker attacks that rely on jamming the wireless link from the key fob to the receiver, while the attacker is able to receive the signal from the key fob. In this paper, we show that typical envelope receivers that are often used in remote keyless-entry systems are highly vulnerable to pulsed interference as compared to continuous interference. The effects of pulsed interference on envelope detectors are analyzed through both simulations and measurements. An improved receiver design would use synchronous receivers instead, which are not very sensitive against pulsed interference. [ABSTRACT FROM AUTHOR]

In this paper, the interference emission levels of domestic induction heating appliances, which are tested out by the triple-loop antenna proposed by Van Veen and Vergerboet, are analyzed to estimate the measured values from numerical simulations. The purpose of this study is to propose an alternative method to evaluate the emission level of consumer goods in the early stages of the development procedure, prior to perform measurement in a prototype. The constitutive parts of the system have been separately analyzed and modeled, including the equipment under test. Three different blocks have been considered: the inductor heating system, the magnetic coupling between the electromagnetic fields of the system and the output levels of sensor antennas, and, finally, the processing performed by the electromagnetic interference receiver. The description given in this paper provides interference levels at frequencies ranging from the operational switching frequency of the apparatus, typically few tens of kilohertz, to about 1 MHz. Finally, the proposed analysis is verified by comparison of the numerical estimated emission levels and test measurements. [ABSTRACT FROM AUTHOR]

This paper deals with electromagnetic compatibility simulations at early design stage of equipment or systems development. In this context, expensive simulations based on rigorous modeling are performed, including numerous uncertain variables. The most important configurations are those associated to extreme values of the observed quantity. In this paper, we introduce a variance reduction technique to accelerate the estimation of an extreme quantile of the output probability distribution. The approach is based on using a simple model (at a low computational cost) to identify relevant realizations of uncertain variables in strata partitioning the output space of the model. Application of the method is detailed on a rather simple cable system in order to estimate an extreme quantile level of an interfering current. We show that the extreme current values are obtained at a reduced computational cost compared to a standard empirical quantile estimation. [ABSTRACT FROM PUBLISHER]

In modern electronic products, the noise from high-speed digital parts is likely to interfere with nearby receivers, causing radio-frequency interference (RFI) issues. In this paper, the equivalent dipole-moment models and a decomposition method based on reciprocity theory are proposed being used together to estimate the coupling from the noise source to the victim antennas. The dipole-moment models are extracted from the near fields of the noise source by solving the inverse problem. The tangential electromagnetic fields on a Huygens's surface, which enclose the victim antenna, can be calculated from these equivalent dipole-moment models. Then, the victim antenna only is treated as a radiator. The tangential electromagnetic fields from the radiating antenna on the same Huygens's surface can be obtained. With these two groups of the fields on the Huygens's surface, the reciprocity theory is applied to estimate the coupling from the noise source to the victim antenna. This method is validated by full-wave simulations and measurements of a simple printed circuit board. The proposed method provides convenience to estimate RFI issues in the early design stage and saves the time of RFI simulation and measurements. [ABSTRACT FROM AUTHOR]

This paper provides qualitative and quantitative values for the received interference power at the antenna ports of automotive radars as well as the probability of their occurrence for actual and future, not yet measurable traffic scenarios on main roads. The influence of the environment, the road traffic behavior, and the radar penetration rate for a defined antenna configuration can be observed. The basis for the analyses are ray-tracing based simulations in order to achieve adequate predictions for the received power levels due to multipaths. The results show that for a radar penetration rate of 100%, the difference between the strongest overall incoherent received interference power level and the level that is received in 90% of the time is up to 7 dB, dependent on the antenna placement and the environment. [ABSTRACT FROM PUBLISHER]

The electromagnetic characterization of on-chip interference generation mechanisms provides new and valuable insights to deal with substrate coupling. In this paper, we describe interference generation from a new perspective that allows us to determine which are the dominant contributions to substrate coupling as a function of the substrate technology option, the device architecture, and the specific operational configuration. This approach is also used to assess the effectiveness of on-chip isolation structures as a function of the aggressor and different grounding strategies. From this analysis, design recommendations are derived to minimize substrate-induced interference. [ABSTRACT FROM AUTHOR]

This study deals with an electromagnetic compatibility (EMC) problem of fiber cable in disturbing electric field. Lightwaves that emerge from the output endface of the fiber are intensity modulated, phase shifted, or modulation frequency multiplied under special conditions. In this paper, theoretical investigation of the effect of interfering electric fields on the bit error rate of digital signals propagating originally in an optical fiber is presented for the EMC evaluation. Theoretical analysis and specific numerical examples show that depending on the required EMC level, the unshielded fiber may not be immune to interference of electromagnetic fields. [ABSTRACT FROM AUTHOR]

This paper reflects a part of electromagnetic susceptibility studies conducted on active circuits. An electromagnetic interference (EMI) is injected on a 5 GHz monolithic voltage-controlled oscillator (VCO). This circuit is implemented on a 0.35 μm BiCMOS SiGe process. Injection locking and pulling are put in evidence when the circuit is subject to a high frequency interference with possible frequency band widened with respect to the oscillation frequency band of the VCO. A simulation process based on envelope-transient method is presented. Its main goal is to predict the behavior of the VCO under injection with interference signal power ranging from low to high level. [ABSTRACT FROM PUBLISHER]

An electromagnetic compatibility (EMC) prediction method is proposed to overcome the insufficiency of the single frequency threshold and prediction methods of statistical analysis. Two prediction models are established based on different sensitive parameters by analysis of the interference mechanism. Effect index is defined to predict EMC. If the effect index reaches or exceeds 1, the communication equipment will be disturbed. The radiation test platform of multifrequency in-band interference is designed, with two different types of communication radios as the equipment under test (EUT). The sine and amplitude modulation (AM) wave, dual-frequency, and tri-frequency radiation tests were performed. Test results show that the sensitive parameter of equipment can be distinguished by sine and AM wave susceptibility threshold; all of the effect indexes of EUT I which is sensitive to peak-field strength exceed 1 and all of the effect indexes of EUT II which is sensitive to average power are around 1. For reducing the model error, the modified Model I is proposed and the effect indexes of EUT I are about 1.1. The method in this paper can effectively solve the problem of multifrequency in-band EMC prediction for the communication equipment and improve EMC standards. [ABSTRACT FROM PUBLISHER]

The paper presents a simple time-domain model for the nonlinear behavior of the jitter of a clock path due to electromagnetic interference on the power supply. A programming algorithm based on the model is developed to calculate the numerical value of the jitter. Transistor-level simulations and test-board measurements are performed on clock paths of various lengths to verify the jitter model. Good agreement between the experiments and MATLAB calculations are observed over wide ranges of interference frequencies and amplitudes. Interesting phenomena, such as the jitter-minimum shift and jitter inflection, can be explained and precisely predicted using the jitter model. An analytical equation is derived for the relationship between the interference frequency and amplitude for the jitter-minimum. The model requires only simple information from the gate circuit for the jitter calculation. It can be further developed into an analytical tool for predicting clock jitter under external electromagnetic interference. [ABSTRACT FROM AUTHOR]

Considering the potential interference of ultrawideband (UWB) on OFDM-based wireless communication systems, this paper studies coexistence issue between UWB with both impulse radio (IR) and multiband (MB) modulation and IEEE802.11n, WiMAX, and LTE downlink systems, using physical layer modeling strategy. According to the physical characteristics of UWB and the victim systems, entire physical layer models are set up. Based on the requirements of bit error rate (BER) and receiver sensitivity of the three victim systems, the emission limits of UWB are respectively obtained. Compared with a method based on interference to noise ratio (I/N) criteria, this method reflects the effect of the actual systems, so the conclusion can provide the reference to formulating the frequency spectrum of UWB within the operating frequency bands of the victim systems. Besides, we also reveal that IR-UWB should be more strictly regulated compared with MB-OFDM because of its time domain characteristic. [ABSTRACT FROM PUBLISHER]

In this paper, a new methodology to characterize common-mode chokes is presented. It is based on a model where common-mode and differential-mode interference is separated into different ports. This methodology is used to explain modal conversion inside common-mode chokes, predict the common-mode and differential-mode conducted emissions when common-mode chokes are connected to electric devices, and improve the filtering performance of common-mode chokes by finding the optimal common-mode choke parameters. [ABSTRACT FROM PUBLISHER]

In a compact dual-planar electromagnetic (EM) bandgap (EBG) microstrip structure, patches are etched periodically in the ground plane to prohibit the propagation of EM waves in certain frequency bands so as to provide filtering functionality. However, the existence of the etched patches in the ground plane becomes a concern in terms of EM compatibility (EMC) and EM susceptibility (EMS). These structures might be prone to EM interference from nearby circuit components as compared to a microstrip filter with a perfect ground plane. In this paper, we study the EMS of a dual-planar EBG filter structure to a microstrip line in close proximity. This study examines the coupling effects of a nearby microstrip line on the performance of the EBG structure when the microstrip line is transmitting a signal and when it is not transmitting a signal. When the microstrip line is transmitting a signal, the effects of the working frequency and the direction of the signal on the coupling to the EBG structure are studied. Experimental and numerical work are presented, analyzed, and verified. The results obtained are useful for the applications and integrations of EBG microstrip structures to microwave circuits. They are useful for EMC and EMS studies of other patterned ground structures/defected ground structures. [ABSTRACT FROM PUBLISHER]

The paper analyzes the test setup required by the International Electrotechnical Commission (IEC) 61000-4-4 to evaluate the immunity of electronic equipment to electrical fast transients (EFT5), and proposes an electrical model of the capacitive coupling clamp, which is employed to add disturbances to nominal signals. The study points out limits on accuracy of this model, and shows how it can be fruitfully employed to predict the interference waveform affecting nominal system signals through computer simulations [ABSTRACT FROM AUTHOR]

Static electrification of the airframe can often cause electromagnetic interference on aircraft radios. Triboelectric charging, occurring when an aircraft is operated in precipitation, raises the aircraft potential until corona discharges occur from points of high dc field on the aircraft. These corona discharges generate noise that is coupled into antenna systems installed on the aircraft. The characteristics of electrostatic accumulation on the surface of carbon fiber composite airplanes are studied in this paper. The differences in electrostatic accumulation between carbon fiber composite airplanes and metal airplanes are also demonstrated. Based on the E fields radiated by an electrostatic discharge (ESD) current, a model of ESD in composite airplanes is established. As is shown, the induced currents excited by the ESD can successfully predict the interference to the airborne antennas in the frequency and time domains, providing a reference for composite airplane design [ABSTRACT FROM AUTHOR]

This paper examines the probability that any millimeter-wave radar systems will interfere mutually by considering spatial, temporal, and operational frequency-related overlaps. It examines the nature and magnitude of the interference under different conditions and for different sensor types before concluding that in an overlapping frequency band, the probability that interference will occur is high. It goes on to demonstrate that, though there are some forms of interference that can be identified and controlled, there are others which are impossible to isolate, resulting in degraded target detection performance and tracking. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to evaluate different integrated-circuit substrate technology options in terms of interference coupling. It is based on the electromagnetic characterization of the different substrate configurations as radial multilayered dielectric lossy open waveguides and the selection of the propagation modes that effectively contribute to substrate coupling. In addition, attenuation patterns are obtained for different technologies, doping profiles, frequencies, and interference mechanisms in order to provide a tool for early interference prediction, electromagnetic compatibility performance evaluation and floorplan strategy definition. [ABSTRACT FROM AUTHOR]

In practice, the detailed geometry information of an off-the-shelf antenna is unavailable. To achieve the estimation of radio frequency interference to an airborne patch antenna with available information, this paper proposes to utilize an equivalent model of the patch antenna. The equivalent model is derived based on the patch antenna's radiation pattern. It shows the same radiating and scattering performances as the original patch antenna. Since, no effective port or phase information is provided by the equivalent model, the reaction theorem was employed to calculate the interference without such information. Simulation and measurement results show that the proposed method can effectively estimate the interference to patch antennas with limited information. Furthermore, it avoids direct modeling of the complex structure of patch antennas and reuses the radiating fields of equivalent models which significantly reduces the computation time and memory cost. [ABSTRACT FROM PUBLISHER]

A common source of noise for digital communication systems is the radiated transient interference. As an example, it has been reported that the degradation is produced to the Global System for Mobile (GSM)-Railway signaling system when the impulsive noise is generated by sparks caused by the discontinuity between the catenary and the pantograph. Concerning the measurement and evaluation procedures defined in the electromagnetic compatibility standards, they are not suitable for these types of transient disturbances. Therefore, new techniques must be developed to determine, with a high confidence level, the degradation that impulsive noise will produce in communication systems. In this paper, novel time-domain measurement procedures are carried out to acquire transient interferences generated by sparks properly. Moreover, two different evaluation methodologies, employing base-band simulation and amplitude probability distribution detector, are used to analyze the impact of the disturbance applied into a GSM system interference scenario. Finally, the results obtained with the developed methodologies are successfully compared with a reference measure where the GSM downlink channel quality is monitored by a mobile station test unit. [ABSTRACT FROM AUTHOR]

Electromagnetic compatibility problems have become more important with the increasing number of antennae integrated into a single communication platform. Traditional methods based on adaptive interference cancelation (AIC) systems have been widely adopted for removing electromagnetic interferences. Usually, these methods may have lower interference cancelation ratio (ICR) since the AIC gain is finite. For overcoming this problem, a feed-forward control method can be used to significantly increase the ICR value by feeding the proper interference signal to the residual error signal. In this paper, a feed-forward control method based on analog adaptive interference cancelation (FAAIC) system has been developed and its corresponding time-domain characteristics of “weights” and “residue error” have been comprehensively studied. The optimal coefficients for feed-forward control have been obtained with the relation of the null shifts of the correlators. The influence of null shifts to feed-forward control is also analyzed. Compared with a traditional analog adaptive interference cancelation system, the average convergence speed of FAAIC is the same and the effect of interference cancelation can be improved remarkably. The experimental results have demonstrated the feasibility of the developed FAAIC system. [ABSTRACT FROM AUTHOR]

A fully operational 4G long-term evolution (LTE) base station is tested in a reverberation chamber to analyze its performance in the presence of a multipath environment, typical of wireless and vehicular communications. Transmission quality parameters are measured ranging from the empty chamber situation (very rich multipath channel) to a very high loading condition to mitigate multipath. In that way, both outdoor and indoor propagation are accounted for. A large attenuation is inserted between the transmitter and the antenna to reduce the signal received by the user to real-life values encountered in both outdoor and indoor environments. In these scenarios, operators may choose to transmit a constant power spectral density throughout all LTE spectrum, or to increase the energy of control channels at the expense of data channels in order to enforce transmission and provide better quality to the user, especially in poor radio conditions. This is called “power boosting,” and its effect is analyzed in this paper. [ABSTRACT FROM AUTHOR]

The design of robust receivers in environments with strong impulsive noise may be challenging due to their high-amplitude events and their rare but nonnegligible occurrence. In substation environments, these impulsive noises are predominant. They are induced by corona discharges such as electrical arcs or partial discharges in the air. The emitted radiations can occupy a wide range of frequencies typically reaching a few gigahertz with very high amplitude. In this paper, we develop a generalized model of impulsive electromagnetic interference induced by corona discharges for wireless channels. Radiations emitted by these sources are generally transient impulses, their occurrences follow cyclostationary process, due to their generation by an alternative current. In this model, we both take into account the physical mechanism of these discharges and the induced electromagnetic radiations. Experimental results validate the approach in terms of first- and second-order statistics such as amplitudes, interarrival time, occurrences, and power spectrum densities of impulsive transient noise. [ABSTRACT FROM PUBLISHER]

The terrestrial-trunked radio (TETRA) specification is produced by the European Telecommunication Standards Institute for private mobile radio systems. We investigated the resilience of TETRA against intelligent intentional electromagnetic interference (IEMI) with low amplitude. Low power signals interfering with the higher layers of the system have the advantage of staying covert. The analysis shows that if the access assignment channel is corrupted, the mobile stations cannot start conversations with the base station. TETRA's modulation scheme is also investigated. $\pi$/4 differential quadrature phase shift keying (QPSK) is interfered with a continuous wave and a QPSK signal. The results show that a continuous wave created the largest error vector magnitude, but creates a peak in the received spectrum. The power of the QPSK signal, however, is distributed over a bandwidth and is more difficult to detect than the continuous wave in the received spectrum. From this, we conclude that the QPSK signal functions is more effective as an intelligent interference signal compared to a continuous wave. In this paper, it is shown that it is possible to create an IEMI that combines the vulnerability in the TETRA protocol with the QPSK signal to disrupt the service to the communication system, while staying covert. [ABSTRACT FROM PUBLISHER]

The development of connected devices and their daily use is presently at the origin of the omnipresence of Wi-Fi wireless networks. However, these Wi-Fi networks are often vulnerable, and can be used by malicious people to disturb services, intercept sensitive data, or to gain access to the system. In railways, trains are now equipped with wireless communication systems for operational purposes or for passenger services. In both cases, defense strategies have to be developed to prevent the misuses of the networks. The first objective of this study is to propose a monitoring solution, which is independent of the communication networks, to detect the occurrence of attacks. The second objective is to develop a method that is able to classify attacks of different types: the intentional electromagnetic interference, i.e., jamming attacks and the protocol-based attacks. This study focuses on the IEEE 802.11n Wi-Fi protocol. To perform these analyses, we propose to monitor and to analyze electromagnetic (EM) signals received by a monitoring antenna and a receiver collecting the EM spectra. After that, we build a classification protocol following two steps: the first consists in the construction of a support vector machine (SVM) classification model using the collected spectra, and the second step uses this SVM model to predict the class of the attack (if any). A time-based correction of this prediction using the nearest neighbors is also included in this second step. [ABSTRACT FROM AUTHOR]

It has been demonstrated that the amplitude probability distribution (APD) of an interfering signal provides an approximation for the bit error probability (BEP) of a radio communication system subjected to interference. The expression for BEP can be applied to the definition of emission limits for protecting a radio system. For communication systems employing multilevel modulation, the expression in some cases underestimates the maximum BEP when the interference is impulsive. In this paper, an improved BEP expression that removes the underestimation risk is derived considering the probability of multiple bit errors caused by one symbol error. On the basis of the new expression, a method of defining emission requirements is proposed by introducing a limit line that restricts the slope of the APD curve. [ABSTRACT FROM PUBLISHER]

The Global System for Mobile communications—Railways (GSM-R) is being deployed in different countries to develop an efficient communication-based train control (CBTC) system. GSM-R participates to achieve railways interoperability, replacing noninteroperable CBTC on existing networks and, thus, facilitating cross-border train circulations. GSM-R ensures voice and data transmissions between trains and control centers and also between trains. As any radio equipment, it is subject to electromagnetic (EM) disturbances present in the railway environment. Therefore, the quality of GSM-R transmissions can deteriorate. It is then important to evaluate and predict the effect of these disturbances in order to avoid any loss of train operational capacity. After an overview of the methods used for the characterization of the EM environment, we describe the GSM-R and the EM disturbances that can affect its operation. The reasons why the existing characterization methods are not fully adapted to the GSM-R are highlighted. The general principle of classification is briefly recalled. The rest of this paper develops the methodology proposed to perform the classification of transient EM noises and the presentation of a test bench and its associated experimental results. Finally, an application to an add-on electromagnetic compatibility supervising equipment installed on board the train is described. [ABSTRACT FROM PUBLISHER]

Today, no simple methods are available for measurements of interference signals that give a proper indication of the impact in terms of the bit error probability (BEP) on a digital radio receiver. Such measure should quantify the corresponding impact and the measurements should be relatively easy to perform. By only using the root mean square (RMS) value of the interference average power the BEP can be underestimated with several magnitudes. To address this problem, an impulsiveness correction factor (ICF) has earlier been proposed to adjust for these errors. The ICF opens up for considerably more accurate BEP estimations whereas the simplicity in the calculations is maintained. However, how to determine the ICF for an arbitrary interference source through measurements has not earlier been known. In this paper, we show that the ICF can be obtained in two alternative ways. One way is to use the measured amplitude probability distribution (APD). The other way is to use the peak- and RMS values from standard measurement detectors. Both methods take the interference waveform properties into consideration and the BEP can thus be more accurately estimated. [ABSTRACT FROM PUBLISHER]

In this paper, a complete new methodology for the automated design of power-line filters is presented and tested. It is based on rigorous characterizations of power-line-filter components, devices under test, and line-impedance stabilization networks (or power-line networks) by means of S-parameter and interference measurements. The implemented automated design tool is able to find an optimal power-line filter for a given device under test under constraints such as cost or number of components, drastically reducing the design time as compared to the usual trial-and-error practice. Since the features of common-mode chokes are highly dependent on the 50-Hz current levels flowing through them, a measurement system of common-mode chokes under 50-Hz load conditions has also been developed and tested in order to complement the automated design tool. The whole system has been successfully validated by means of experimental measurements. [ABSTRACT FROM PUBLISHER]

In recent years, industrial wireless applications have emerged rapidly. The use of short-range radio communication systems in factories increases the flexibility in industrial processes by reducing the use of cables. However, the technological challenges involved in wireless communication in industrial environments are not trivial; they result in disadvantages with respect to reliability and security because of electromagnetic interference. To gain an understanding of the performance limits of these wireless applications, knowing the characteristics of these environments is essential. In this approach, amplitude probability distribution and rms delay spread measurements have been used to perform electromagnetic site surveys in three factory automation infrastructures. [ABSTRACT FROM PUBLISHER]

The trend of electronic systems toward higher integration and higher performance has also brought new challenges to the design of radio transceivers. The decrease of switching times accompanied by the increase of clock speeds, data rates, and interconnection speeds contribute to improve the overall system performance. At the same time, they also affect wireless communications due to an increment of the emissions of electromagnetic radiation. In this paper, we show that the statistics of the baseband components of the noise follow the K-distribution. The one-sided version of this distribution has been derived before as a model for the envelope of sea echo in radar and sonar, however, we show here that its two-sided version can also be used to model the interference noise that affects a transceiver located inside a computer platform. The model shows good agreement with experimental measurements. Also, a closed-form expression of the bit error rate (BER) and some bounds are computed. [ABSTRACT FROM PUBLISHER]

This paper deals with the investigation of interference coupling and transmission characteristics within the frequency range of very high frequency (VHF) voice transmission and navigation systems in airplanes. Possible measuring methods are analyzed for their applicability in the determination of transfer functions. It is revealed that, due to the complex harness with many crosspoints and junctions, a separation of cable. and field-coupled VHF interference is neither useful nor possible. Radiation coupling between the cable harness and the inner fuselage volume is not only important but also turns out to be the dominating mechanism for the description of electromagnetic compatibility transfer characteristics in the VHF frequency range. [ABSTRACT FROM AUTHOR]

In this paper, we extend an existing heuristic algorithm for fixed-frequency assignment in cellular communication networks in order to account for the effects of adjacent channel interference (Act). Our algorithm utilizes estimations of carrier-to-interference ratio instead of binary channel separation constraints. The extended algorithm avoids Overoptimistic frequency assignments that do not guarantee interference-free operation environments. Its cost is the increased computational complexity. We estimate the upper bound of the algorithm's complexity when ACI is taken into account. Simulations demonstrate that despite the theoretical high increase in complexity, the algorithm is suitable even for a quasi-dynamic frequency assignment scheme in practical situations. The algorithm enhances the spectrum utilization in cellular networks while reducing harmful interference. [ABSTRACT FROM AUTHOR]

The uplink performance of a real fourth-generation long-term-evolution (LTE) frequency-division multiplexing base station was observed by adopting a reverberation chamber as propagating environment. In the downlink direction, the reception of the LTE signal is limited to mobile station receivers. On the other hand, different reception schemes could be implemented by the base station in the uplink direction. Interference rejection and coordinated multipoint reception criteria are based on spatial diversity and are analyzed in a rich multipath environment. These options could be susceptible to impairments due to the presence of Gaussian noise, also including the more realistic case of a discontinuous noise source. The testing session was carried out under a collaboration program between TIM S.p.A., Nokia, and Università Politecnica delle Marche, and it ended up by introducing envisioned reception solutions of the base station in a live customer's cellular network. [ABSTRACT FROM PUBLISHER]

It remains a typical engineering problem demanding prompt solution to measure the electromagnetic radiation of equipments accurately in the complicated electromagnetic environment. A new measurement method for ambient interferences suppression in an in situ radiated emission test is proposed. Technologies of signal processing such as side lobe cancellation and frequency section have been adopted to filter background interferences in a smart way. The suppression effects on different kinds of interferences are studied. The simulation results show that the method can simultaneously suppress multiple interferences, which are either narrowband or wideband, stable or transient. The performance of the method is evaluated by experiments as well. The experimental results show that the pulse modulation interferences can be suppressed remarkably, guaranteeing the radiation characteristic of the testing equipment free of distortion at the same time. This novel method can not only make up shortages of traditional virtual chamber technology, but also has more handleability and convenience for the electromagnetic compatibility in situ test. [ABSTRACT FROM AUTHOR]

The high frequency (HF) radio channel is highly variable and unpredictable. On the other hand, being largely utilized around the globe, the HF spectrum is densely occupied, characterized by significant levels of interference. Therefore, spectral congestion is always a severe issue to be addressed. One year data (June 2012–June 2013) of HF spectral occupancy measurements collected by a dedicated measurement system installed in Cyprus have been examined in order to characterize and model the HF interference environment over the eastern Mediterranean region. An investigation into the short-term temporal variability of HF spectral occupancy for selected indicative allocations has been conducted. With a view to extend the data analysis from descriptive to predictive and from qualitative to quantitative, time series analysis has been applied to model the HF spectral occupancy of the indicative ranges in the HF spectrum. We categorized different time series models for different occupancy patterns. Analysis for three broadcast allocations covering three different portions of the HF spectrum namely, lower (5.950–6.200 MHZ), middle (11.650–12.050 MHZ), and upper (17.550–17.900 MHZ), is presented. Results of this investigation are expected to be useful for radio system design and frequency management strategies. [ABSTRACT FROM PUBLISHER]

Research and development are currently being performed to transform the US's utility electric grid into a “smart grid [1], [2].” Smart meters are among the first intelligent metering devices used within the “smart grid” concept. They have been deployed in thousands of commercial and residential electrical installations around the US [3], [4]. While the wide-scale deployment of these devices has initially proven very successful, there is still much that is unknown about how they will impact the long-term operation of a large utility grid or the electrical devices sourced by them [5]. One such device, whose operation appears to be impacted by the smart meter, under specific conditions, is a ground-fault circuit interrupter (GFCI). It has been reported that the RF transmissions from smart meters can induce false tripping events on GFCI outlets installed on temporary construction poles. In an effort to understand why this may happen, a research study, which is presented here, has been performed to understand the correlation between RF transmissions and GFCI tripping events on construction poles. [ABSTRACT FROM AUTHOR]

A statistical method is developed for characterizing wideband emissions from planar antennas and circuits containing multiple radiating elements. It is shown how the space-time and space-frequency correlation functions for source currents can be deduced from near-field measurements. These correlations produce additional spectral distortion of the emitted near field, over and above the far-field spectra of individual elements and their combined spectrum for uncorrelated sources. For an arbitrary configuration and number of emitting dipoles, the contribution to this distortion by pairwise correlations is fully calculable from the second-order covariance theory. Simulation results for a 2\times2 dipole array and near-field measurements on an L-shaped microstrip antenna with wide-band excitation demonstrate and validate the feasibility of the method and the theoretically predicted spectral distortion based on pairwise correlations only. [ABSTRACT FROM PUBLISHER]

Changes in electromagnetic energy absorption were studied in the presence of subcutaneous antenna devices implanted for biotelemetry applications. We examined the influence on energy absorption of these devices as passive metallic implants when incoming RF energy is present. We aim to contribute to the optimization of the implant location in order to reduce a possible energy increase on tissues. The research was carried out using electromagnetic modeling based on the finite-difference time-domain method. The calculations were performed in terms of electric field and SAR distributions calculated for five different frequency bands (from 0.9 to 17 GHz) covering most current telecommunications standards. The focus was on both far-field and near-field exposure. The results lead us to propose the subcutaneous zone nearest to the surface of the skin as the most appropriate place to locate these devices. [ABSTRACT FROM AUTHOR]

A new method of evaluating the interference to a wireless LAN with a built-in antenna using a gigahertz transverse electromagnetic (GTEM) cell is proposed. The GTEM cell can generate a wideband electromagnetic field from dc up to several gigahertz with a high spatial uniformity in the cell. This is advantageous for configuring a system for a victim receiver with a built-in antenna. Furthermore, the strength of the interfering electromagnetic field to be applied to the victim can be directly calculated from a given equivalent isotropically radiated power and propagation distance of the interfering signal in free space. It should also be noted that a GTEM has a conductive enclosed structure that is much smaller than typical anechoic rooms. As an example of use of the method, the evaluation of interference between an IEEE 802.11a wireless LAN and a direct-sequence spread-spectrum UWB was conducted. Investigations are further conducted on the effects of the UWB signal on the throughput of the victim wireless LAN system on the basis of bit error rate estimated with measurement results of the amplitude probability distribution of the UWB signal. [ABSTRACT FROM AUTHOR]

The physical mechanism behind electromagnetic interference (EMI) is the coupling of energy between different primary and secondary sources of radiation and components within the package or chassis. This coupling can be either through conduction or radiation. However, regardless of the coupling mechanism, surface currents are needed to support the electromagnetic fields that eventually cause radiation, which in turn, constitute the EMI in the victim component. Minimizing these surface currents is considered a fundamental and critical step in minimizing EMI. In this work, we address novel strategies to confine surface currents. Unlike the traditional use of lossy materials and absorbers, which can be costly and can suffer from considerable disadvantages including mechanical and thermal reliability leading to limited life time, we consider the use of electromagnetic band gap (EBG) structures. These structures are inherently suited for surface current suppression. Their design is straightforward, and they are inexpensive to implement and do not suffer from the limitation of the previous methods used for the type of EMI suppression previously described. The effectiveness of the EBG as an EMI suppresser will be demonstrated using numerical simulations and measurements. [ABSTRACT FROM AUTHOR]