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The L-band digital aeronautical communications system (LDACS) is the future air–ground communications technology currently undergoing the International Civil Aviation Organization standardization process. As LDACS is intended to operate in the frequency band 960–1164 MHz, compatibility tests between LDACS and the legacy systems operating in this frequency band are necessary to ensure that no system is harmfully interfered. One of these systems is the joint tactical information distribution system (JTIDS), a technology employed by the tactical data link Link 16. In this paper, we present the results of an impact assessment of LDACS on JTIDS conducted through simulations. The extent of the impact has been quantified by simulating a wide variety of interference configurations, which are expected to cover most realistic interference conditions between LDACS and JTIDS. Baseband simulation models of both systems have been implemented and an interference scenario between LDACS and JTIDS has been defined. To evaluate the impact, the degradation of the signal-to-noise ratio (SNR) of JTIDS by the presence of LDACS has been determined. Default JTIDS transmissions, where the information is repeated at distant frequencies, do not show a significant degradation by the presence of strong LDACS interference, with an SNR loss lower than 1 dB in any considered interference scenario. Comparatively, a certain dependency on the specific LDACS deployment is noticeable for less protected JTIDS transmissions. Based on the observed interdependencies, recommendations for the deployment of LDACS are given in this paper, such that the impact of LDACS on JTIDS is minimized. [ABSTRACT FROM AUTHOR]

This paper investigates the benefits of incorporating full-duplex (FD) into an underlaid device-to-device (D2D) cellular network via centralized and distributed power control mechanisms. In the considered system, D2D users operate in an FD mode under the adverse effect of realistic residual self-interference, and their locations are modeled by a homogeneous spatial Poisson point process. By first considering a centralized power control scheme, we first formulate an optimization problem that maximizes the D2D link sum-rate under the constraint on minimum target signal-to-interference-plus-noise ratio (SINR) at each user. Since the problem is nonconvex, we propose a difference of convex based method to transform the problem into a sequence of convex subproblems which can be solved efficiently. The obtained solutions help to calculate the coverage probability of both cellular and D2D links, showing that a very high coverage probability of cellular link can be achieved while successfully supporting a large number of active D2D links. In the second part of the paper, we consider a distributed power control scheme where only the local channel state information of direct link between respective D2D users is needed. By utilizing the tools of stochastic geometry, we derive closed-form approximations of coverage probabilities for both cellular and D2D links. Specifically, we apply Laplace transforms and novel approximations that accurately approximate the expected values of fractional and exponential functions of random variables to obtain the distribution functions of SINRs at the base-station and D2D users in a closed form. By further taking the average over the distributions of cellular and D2D link distances, we then arrive at the closed-form approximations of cellular and D2D coverage probabilities. In addition, based on the approximation of D2D link coverage probability, an analytical expression for the D2D link sum-rate is also obtained, and it can be effectively calculated. [ABSTRACT FROM AUTHOR]

This paper proposes interference mitigation techniques for provisioning ultrareliable low-latency wireless communication in an industrial automation setting, where multiple transmissions from controllers to actuators interfere with each other. Channel fading and interference are key impairments in wireless communication. This paper leverages the recently proposed “Occupy CoW” protocol that efficiently exploits the broadcast opportunity and spatial diversity through a two-hop cooperative communication strategy among distributed receivers to combat deep fading, but points out that because this protocol avoids interference by frequency division orthogonal transmission, it is not scalable in terms of bandwidth required for achieving ultrareliability, when multiple controllers simultaneously communicate with multiple actuators (akin to the downlink of a multicell network). The main observation of this paper is that full frequency reuse in the first phase, together with successive decoding and cancellation of interference, can improve the performance of this strategy notably. We propose two protocols depending on whether interference cancellation or avoidance is implemented in the second phase, and show that both outperform Occupy CoW in terms of the required bandwidth and power for achieving ultrareliability at practical values of the transmit power. [ABSTRACT FROM AUTHOR]

A novel humidity sensor based on a specially designed polyimide coated dual-mode fiber (DMF) is presented in this paper. The parameters and index profile of the DMF used in the experiments are specially designed to support only two modes, LP01 and LP02, propagating in the fiber at the operational wavelength, and the interference between these two modes produces a polarization-independent transmission spectrum. An in-line Mach–Zehnder interferometer is constructed by splicing a section of DMF between two pieces of standard single-mode fibers and employed in the detection of the surrounding relative humidity (SRH) of the environment. In the experiments, because the volume of the polyimide film coated on the DMF changes with SRH and thus produces the strain imposed on the DMF section, the interference dips in the transmission spectrum shift monotonically with the increasing SRH. According to the previous research, the strain sensitivities of the DMF used in this paper increase significantly when the peak wavelengths approach the critical wavelength. Therefore, in the experimental results observed, the experimental sensitivity is 153.5 pm/%RH in the SRH range of 30%RH–98%RH, which is over ten times larger than the largest sensitivity (15 pm/%RH) of polyimide-coated fiber Bragg grating reported in the literature. The proposed humidity sensor has advantages of robust, low cost, and ease of fabrication, which suits several practical applications in monitoring the SRH, especially when high sensitivity measurement is required. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a joint resource allocation problem based on cognitive radio (CR) techniques for user equipment with multi-homing capabilities. We consider a heterogeneous wireless medium where users in overlapping coverage areas simultaneously communicate with different base stations and access points. Currently, existing works assume that the working frequency bands of different networks are separated. Unlike these works, this paper focuses on the multi-homing networks, which can share spectrum resources of each other to enhance the resource utilization efficiency. Based on spectrum sensing and spectrum sharing techniques in CR, we propose and then formulate an uplink joint original bandwidth, detected hole bandwidth and power allocation method. Specifically, the formulated optimization problem is a mixed integer nonlinear optimization problem. We adopt the continuity relaxation method to further transform it into a convex optimization problem and then solve it by Lagrange dual solution. A suboptimal method is further proposed with a reduced system overhead. Simulation results demonstrate the significantly improved performance of our proposed methods (both optimal and suboptimal) in terms of system throughput and energy efficiency over a joint resource allocation benchmark. Our results also indicate that the suboptimal strategy can indeed reduce the system overhead remarkably. [ABSTRACT FROM AUTHOR]

This paper proposes a joint read equalization scheme for interlaced magnetic recording (IMR) employing an array of readers, where multi-reader captured waveforms from asynchronously recorded tracks are jointly processed for single or multiple track data retrievals. In the array-reader-based IMR (ARIMR), the inter-track interference (ITI) collected from one reader is not necessarily synchronized to the other readers, especially in the case of a large cross-track separation (CTS) between the readers due to the linear density differentiation between the neighboring tracks. For the efficient mitigation of such asynchronous ITIs, an effective resampling-based joint equalization scheme is proposed in this paper, where multiple readbacks are digitally synchronized for designated target tracks, and joint processing of them suppresses the ITI in the equalized output. Furthermore, the proposed effective synchronization can be applied for joint multi-track retrievals when the CTS of the array reader is closed to the track pitch. For performance evaluations of the proposed joint read equalization scheme, numerical ARIMR channel simulations by the micro-pixelated magnetic channel model are conducted, and a bit error rate performance is evaluated under various configurations. In addition, waveforms captured from a dual-reader hard disk drive are evaluated with the proposed joint read equalization schemes for practical performance measurements of ARIMR. In both evaluations, unfavorable CTS conditions are investigated to account for the dominant skew effect in ARIMR, where the proposed joint equalization scheme enhances the off-track capability performance, especially with the customized configurations of interlaced recording. In overall, ARIMR with joint read equalization shows the potential of an areal density capability gain and a doubling of the data transfer rate over the conventional perpendicular magnetic recording and legacy IMR. [ABSTRACT FROM AUTHOR]

In the 5 G system, millimeter wave and D2 D communication is beneficial to improve the system capacity and spectrum utilization. This paper studied the resource allocation for D2 D in underlay cellular networks at 73 GHz. In order to reduce the interference between each other, firstly, this paper proposed the regional restrictions on the base station and D2 D receiver.Then, it used the method of linear correlation to select reusable cellular users. Finally, in order to improve the system throughput, it proposed a resource allocation based on interference control under meeting the requirements of quality of service( QoS)of cellular communication and D2 D communication. The simulation results show that the proposed algorithm outperforms the reference algorithm. The algorithm can effectively improve the system throughput and spectrum efficiency. [ABSTRACT FROM AUTHOR]

In this paper, we consider the downlink of a multi-cell multiple-input multiple-output system and find the jointly optimal number of base station (BS) antennas and transmission powers that minimize the power consumption while satisfying each user’s effective signal-to-interference-and-noise-ratio constraint and the BSs’ power constraints. Different from prior work, we consider a power consumption model that takes both transmitted and hardware-consumed power into account. We formulate the joint optimization problem for both single-cell and multi-cell systems. The closed-form expressions for the optimal number of BS antennas and transmission powers are derived for the single-cell case. The analysis for the multi-cell case reveals that increasing the number of BS antennas in any cell always improves the performance of the overall system in terms of both feasibility and total radiated power. A key contribution of this paper is to show that the joint optimization problem can be relaxed as a geometric programming problem that can be solved efficiently. The solution can be utilized in practice to turn on and off antennas depending on the traffic load variations. The substantial power savings are demonstrated by simulation. [ABSTRACT FROM AUTHOR]

This paper aims at studying the achievable data rate of discrete cosine transform (DCT)-based multicarrier modulation (MCM) systems. To this end, a general formulation is presented for the full transmission/reception process of data in Type-II even DCT and Type-IV even DCT-based systems. This paper focuses on the use of symmetric extension and zero padding as redundancy methods. Furthermore, three cases related to the channel order and the length of the redundancy are studied. In the first case, the channel order is less than or equal to the length of the redundancy. In the second and third cases, the channel order is greater than the length of the redundancy; the interference caused by the channel impulse response is calculated, and theoretical expressions for their powers are derived. These expressions allow studying the achievable data rate of the DCT-based MCM systems, besides enabling the comparison with the conventional MCM based on the discrete Fourier transform. [ABSTRACT FROM AUTHOR]

In this paper, we consider the full-duplex decode-and-forward wireless-powered relaying system, which employs energy harvesting protocol with power splitting. The robust joint optimum relay transmit beamformer and power splitting factor are obtained for the quality of service (QoS)-aware problem for the first time in the literature. The optimum solution is found by analyzing the Karush–Kuhn–Tucker conditions, thanks to the effective reformulation of the problem in an equivalent and simplified manner. In addition, the signal-to-interference-plus-noise ratio (SINR) maximization problem is investigated in order to find the robust optimum solution. The simulation results verify the optimality of the proposed method compared with the sub-optimum one which is presented by Zhao et al.. In the next part of this paper, the considered system is generalized by employing multiple receive antennas at the relay. Both QoS-aware and SINR maximization problems are considered. The near-optimum relay transmit and receive beamformers as well as power splitting factor are found by optimizing the variables alternately. First, transmit beamformer and power splitting factor are found optimally for a given initial receive beamformer. Then, the optimum receive beamformer is obtained. Relay with multiple-receive antennas is shown to perform better than the single receive antenna relay in terms of SINR and transmission power. [ABSTRACT FROM AUTHOR]

In this paper, a two-tier uplink femtocell network operating in orthogonal frequency-division multiple access is investigated. Femtocell base stations endowed with cognitive capacity can sense the void spectrum of macrocell. We aim at an energy-saving scheme of power allocation for femtocell users. The new idea that performance of Femtocell networks can be analyzed using control theory is proposed in this paper. A simple and novel power control algorithm is designed based on the virtual Proportional-Integral (PI) controller. When considering the maximum power constraints, different from the proof of the convergence via standard interference functions, we establish a linear system with state saturation (maximum power constraint) for femtocell networks, and the power's convergence is verified in theory with iterative linear matrix inequality algorithm. Two introduced control parameters not only guarantee the stability of power control algorithm, but also can adjust the transient response and save energy. Numerical results illustrate the convergence performance and advantages of the PI algorithm. [ABSTRACT FROM AUTHOR]

This paper studied the relationship between the temperature/strain wavelength sensitivity of a fiber optic in-line Mach–Zehnder interferometer (MZI) sensor and the wavelength separation of the measured wavelength to the critical wavelength (CWL) in a CWL-existed interference spectrum formed by interference between LP01 and LP02 modes. The in-line MZI fiber optic sensor has been constructed by splicing a section of specially designed few-mode fiber (FMF), which supports LP01 and LP02 modes propagating in the fiber, between two pieces of single-mode fiber. The propagation constant difference, $\Delta \beta $ , between the LP01 and LP02 modes, changes non-monotonously with wavelength and reaches a maximum at the CWL. As a result, in the sensor operation, peaks on the different sides of the CWL then shift in opposite directions, and the associated temperature/strain sensitivities increase significantly when the measured wavelength points become close to the CWL, from both sides of the CWL. A theoretical analysis carried out has predicted that with this specified FMF sensor approach, the temperature/strain wavelength sensitivities are governed by the wavelength difference between the measured wavelength and the CWL. This conclusion was seen to agree well with the experimental results obtained. Combining the wavelength shifts of the peaks and the CWL in the transmission spectrum of the SFS structure, this paper has shown that this approach forms the basis of effective designs of high sensitivity sensors for multi-parameter detection and offering a large measurement range to satisfy the requirements needed for better industrial measurements. [ABSTRACT FROM AUTHOR]

In this paper, a new transmission scheme, signal space cognitive cooperation, is introduced by applying the idea of signal space diversity in an underlay spectrum sharing decode-and-forward multirelay cooperative network. In the proposed structure, the secondary source signal is rotated by a certain angle and then the source and the secondary best relay transmit the in-phase and the quadrature components of the rotated signal. As a consequence, two source signals, rather than one, are transmitted in two-time slots which improves data rates considerably, compared to the conventional cognitive cooperative schemes. In this paper, proactive relaying mode is used in which the best relay is selected based on the max–min selection criterion before executing the transmission. Considering both statistical and the instantaneous channel state information of the feedback channel between the primary receiver and the secondary network, two power allocation methods are adopted at the source. For both methods, closed-form expressions of error probability are derived. Moreover, asymptotic analysis is performed and diversity gain is obtained to provide further insights about the system performance. Finally, analytical expressions are verified by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

This paper studies the effectiveness of relaying for interference mitigation in an interference-limited communication scenario. We are motivated by the observation that in a cellular network, a relay node placed at the cell edge observes a combination of intended signal and inter-cell interference that is correlated with the received signal at a nearby destination, so a relaying link can effectively allow the antennas at the relay and at the destination to be pooled together for both signal enhancement and interference mitigation. We model this scenario by a multiple-input multiple-output (MIMO) Gaussian relay channel with a digital relay-to-destination link of finite capacity, and with correlated noise across the relay and destination antennas. Assuming a compress-and-forward strategy with Gaussian input distribution and quantization noise, we propose a coordinate ascent algorithm for obtaining a stationary point of the non-convex joint optimization of the transmit and quantization covariance matrices. For fixed input distribution, the globally optimum quantization noise covariance matrix can be found in closed-form using a transformation for the relay’s observation that simultaneously diagonalizes two conditional covariance matrices by congruence. For fixed quantization, the globally optimum transmit covariance matrix can be found via convex optimization. This paper further shows that such an optimized achievable rate is within a constant additive gap of the MIMO relay channel capacity. The optimal structure of the quantization noise covariance enables a characterization of the slope of the achievable rate as a function of the relaying link capacity. Moreover, this paper shows that the improvement in spatial degrees of freedom by MIMO relaying in the presence of noise correlation is related to the aforementioned slope via a connection to the deterministic relay channel. [ABSTRACT FROM AUTHOR]

Accurate alignment of the watch hand is a critical procedure in the industrial production of watches. However, compared with the traditional ideal laboratorial case, the watch-hand alignment suffers various external disturbances from the aged equipment and industrial operating conditions, which seriously influence the alignment precision. To achieve accurate watch-hand alignment in the complex industrial environment, this paper develops a robotic micromanipulation system and proposes a corresponding robust control strategy. First, a micromanipulation system with five degrees of freedom is set up and integrated with an optical microscope. Then, a set of proper machine vision methods is adopted to obtain accurate position information in disregard of the interference terms. Third, the dynamic model of the controlled watch hand is built with consideration of the external disturbances from the production environment. Since the velocity information cannot be observed accurately through the machine vision process, we design a state observer to acquire the position and velocity values for the following control strategy. After that, a sliding mode controller with the radical basis function neural network is proposed to achieve high-precision alignment while resisting the external disturbance. Finally, simulation and experimental results prove that the proposed method can realize the alignment of the watch hand within 6 s with the accuracy of $2\times 10^{-3}$ rad, which is enhanced at least two times compared with the traditional manual method. Note to Practitioners—This paper was motivated by the challenging problem of the watch-hand alignment in the industrial production. Unlike the traditional manipulation, this alignment is subjected to various disturbances from the aged equipment and complex operating conditions, including complex forces at the air–liquid operation interface and the confusing scratches, undesired flaking particles, as well as the reflection of light in the image. Here, we propose a microrobotic system and a robust control strategy to precisely align the watch hand and eliminate the influence from the above disturbances. In the machine vision process for recognizing the object, filtering, contour/corner detection, and template matching methods are adopted to acquire accurate position information despite the interference in image processing. To avoid the disturbance from the complex forces during the alignment, we develop the robust sliding mode controller to guarantee the alignment precision. The experiment results indicate that the proposed system can align the watch hand with the accuracy enhanced at least two times as previous manual method. This paper provides a general solution for micromanipulation under disturbance in industrial production environment. [ABSTRACT FROM AUTHOR]

The theoretical bases of interference research are analyzed in the article, the essence of the concept of "interference" is turned out. The translation of linguistic interference, causes and mechanisms of its appearance, its impact on professional communication are considered in the paper. The publication deals with the manifestations of interference within the limits of imperfect parts of the language and the difficulties of translation caused by the syntactic and punctuation features of the language. Comparison of grammatical systems of contacting languages makes it possible to avoid some of the difficulties caused by interference, because of their conscious comparison. The phenomenon of interference is studied in linguistics, sociolinguistics, psychology, psycholinguistics, methods of teaching foreign languages. Actualization of the linguistic aspect of interference occurs at all levels of the language system and is realized in speech regardless of the speaker's consciousness. Linguistic interference in translation can appear both at the level of morphemes and at the level of words represented by different parts of speech: pronouns, verbs, nouns, adverbs, Participle I, Participle II, prepositions, conjunctions. All interferences covered in the paper have been analyzed. Consequently, interference is one of the factors, one of the engines of language development, linguistic changes that are accumulated and drown in it. In a subordinate plan, mass and frequent interference means the constant mixing of two systems, their more or less mutual assimilation. Thus, identifying areas of linguistic interference, studies have attested interference phenomenon are important for improving language culture. Attracting attention to those areas and units of language where there is a probable occurrence of deviations from the norm under the influence of another language can help to avoid interference. It was emphasized that it is precisely the account of the manifestations of interference in the training of professional intercultural communication and translation that can ensure the effectiveness of the educational process for the preparation of translators. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method to reuse the cyclic-prefix (CP) intervals of an ongoing OFDM link, by another link, without degrading the OFDM link performance. We label the link that reuses the CP-intervals as CPLink, as they use only the CP-intervals of the ongoing link labeled, MainLink. We leverage the fact that the most commonly used OFDM receivers discard the samples in CP-intervals to design the CPLink that ensures below-noise-floor interference at every MainLink-receiver. The key contribution in this paper is the design and study of zero-knowledge CPLink, in which the CPLink-transmitter ensures below-noise-floor interference at every MainLink-receiver with no knowledge about the locations or the number of MainLink-receivers. We analytically show that the zero-knowledge CPLink capacity is positive. For LTE frame structure with 20-MHz bandwidth and 2-km cell-radius, we evaluate the CPLink for two kinds of CPLink-receivers: full-duplex base-station and a half-duplex device. Even for the cell-edge CPLink-transmitters, full-duplex zero-knowledge CPLink data rates can be up to 20 Mbps (60 Mbps) when the CP duration is ~7% (25%) of the data-symbol duration. The half-duplex CPLink rate is 5–40 Mbps when the CPLink-transmitter is within 250 m of CPLink-receiver. CPLink capacity is found to increase near-linearly with the CP duration, thus mitigating CP overhead. [ABSTRACT FROM AUTHOR]

The paper is an attempt to create the definitions of and delimitations between the terms calque, semi-calque, and phraseological hybrid, based on the material collected among the bilingual community of Old Believers in Poland. Many scientfic papers have been written on calques, semi-calques, and phraseological hybrids, contributing to a better understanding of those linguistic phenomena, and deepening the possibilities of their interpretation. Calques, semi-calques, and lexical hybrids have been described in a quite satisfactory way; with reference to phraseology, however, theoretical and methodological discussions are still lacking. Their correct interpretation is key for an analysis of the phraseological store of the bilingual community of Old Believers in Poland. For more than half a century, their Russian dialect has been subjected to an incessant, strong influence of Polish, resulting in the appearance of an increasingly large number of elements borrowed from Polish, especially in the lexical system: borrowings, lexical calques, as well as phraseological calques and semi-calques. [ABSTRACT FROM AUTHOR]

Spectrum awareness techniques have been proposed as a promising solution to improve the utilization of available spectrum bands. However, few works have discussed the feasibility of spectrum awareness techniques in satellite systems. In the scenario of spectrum coexistence between geostationary (GEO) and nongeostationary (NGEO) satellite systems, this paper investigates the issue of blind spot where the spectrum awareness techniques may fail to identify the spectrum holes. Both the uplink and downlink transmissions are analyzed and three key parameters, i.e., altitude of NGEO satellite and antenna diameters of NGEO and GEO earth stations, are considered. Simulation results show that in the uplink, when the NGEO satellite approaches to the GEO satellite with a certain heights, there exists the situation of blind spot. In addition, this paper also provides a specific method to eliminate or reduce the range of blind spot. [ABSTRACT FROM AUTHOR]

Multi-layer broadcast systems distribute services across time and frequency domain by means of power-division multiplexing. Successive interference cancelation is required, in general, in order to extract the content of all services. For a low-complexity implementation, the receiver can obtain the strongest (top-layer) signal assuming underlying signals to behave like thermal noise. The thermal noise assumption may not be valid under certain conditions and a more accurate characterization of the interference could bring improved performance. This paper analyzes the validity of the noise-like assumption considering the power ratio between signals and the required carrier-to-noise ratio for error-free reception. The main contribution of the paper is the proposal of a demapping algorithm that exploits the knowledge of the constellation of underlying signals. Generalized mutual information, performance evaluation, and complexity analysis are provided with the additive white Gaussian noise-like assumptions and with the proposed alternative in order to assess the potential performance improvements that can be achieved. [ABSTRACT FROM AUTHOR]

This paper provides an analytical performance characterization of both the uplink (UL) and downlink (DL) user-centric network multiple-input multiple-output (MIMO) systems, where a cooperating base station (BS) cluster is formed for each user individually and the clusters for different users may overlap. In this model, cooperating BSs (each equipped with multiple antennas) jointly perform zero-forcing beamforming to the set of single-antenna users associated with them. As compared with a baseline network MIMO system with disjoint BS clusters, the effect of user-centric clustering is that it improves signal strength in both the UL and DL, while reducing cluster-edge interference in the DL. This paper quantifies these effects by assuming that BSs and users form Poisson point processes and by further approximating both the signal and interference powers using Gamma distributions of appropriate parameters. We show that BS cooperation provides significant gain as compared to single-cell processing for both the UL and DL, but the advantage of user-centric clustering over the baseline disjoint clustering system is significant for the DL cluster-edge users only. Although the analytic results are derived with the assumption of perfect channel state information and infinite backhaul between the cooperating BSs, they nevertheless provide architectural insight into the design of the future cooperative cellular networks. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive design and analysis of multiple-input multiple-output (MIMO) full-duplex (FD) relaying systems in a multi-cell environment is investigated, where a multi-antenna amplify-and-forward FD relay station serves multiple half-duplex (HD) multi-antenna users. The pivotal obstacles of loopback self-interference (LI) and multiple co-channel interferers (CCI) at the relay and destination when employing FD relaying in cellular networks are addressed. In contrast to the HD relaying mode, the CCI in the FD relaying mode is predicted to double since the uplink and downlink communications are simultaneously scheduled via the same channel. In this paper, the optimal layout of transmit (receive) precoding (decoding) weight vectors which maximizes the overall signal-to-interference-plus-noise ratio is constructed by a suitable optimization problem, and then a closed-form sub-optimal formula based on null space projection is presented. The proposed hop-by-hop rank-1 zero-forcing (ZF) beamforming vectors are based on added ZF constraints used to suppress the LI and CCI channels at the relay and destination, i.e., the source and relay perform transmit ZF beamforming, while the relay and destination employ receive ZF combining. To this end, unified accurate expressions for the outage probability and ergodic capacity are derived in closed form. In addition, simpler tight lower bound formulas for the outage probability and ergodic capacity are presented. Moreover, the asymptotic approximations for outage probability are considered to gain insights into system behavior in terms of the diversity order and array gain. Numerical and simulation results show the accuracy of the presented exact analytical expressions and the tightness of the lower bound expressions. The case of hop-by-hop maximum-ratio transmission/maximal-ratio combining beamforming is included for comparison purposes. Furthermore, our results show that while multi-antenna terminals improve the system performance, the detrimental effect of CCI on FD relaying is clearly seen. Therefore, our findings unveil that MIMO FD relaying could significantly improve the system performance compared to its conventional MIMO HD relaying counterpart. [ABSTRACT FROM AUTHOR]

The integration of local device-to-device (D2D) communications and cellular connections has been intensively studied to satisfy co-existing D2D and cellular communication demand. In future cellular networks, there will be numerous standby users possessing D2D communication capabilities in close proximity to each other. Considering that these standby users do not necessarily request D2D communications all the time, in this paper we propose a hybrid D2D-cellular scheme to make use of these standby users and to improve the rate performance for cellular users. More specifically, through D2D links, a virtual antenna array can be formed by sharing antennas across different terminals to realize the diversity gain of MIMO channels. This paper considers the use of millimeter wave links to enable high data rate D2D communications. We then design an orthogonal D2D multiple access protocol and formulate the optimization problem of joint cellular and D2D resource allocation for downlink transmissions using the proposed scheme. We obtain a closed-form solution for D2D resource allocation, which reveals useful insights for practical system design. Numerical results from extensive system-level simulations demonstrate that the rate performance of cellular users is significantly improved. [ABSTRACT FROM AUTHOR]

The three-tier spectrum sharing framework (3-TSF) is a spectrum sharing model adopted by the Federal Communications Commission. According to this model, under-utilized federal spectrum like the Citizens Broadband Radio Service band is released for shared use where the highest preference is given to Tier-1 followed by Tier-2 (T2) and then Tier-3 (T3). In this paper, we study how a wireless operator, who is interested in maximizing its profit, can strategically operate as a T2 and/or a T3 user. T2 is characterized by paid but ”almost” guaranteed and interference-free channel access while T3 access is free but has the lesser guarantee and also faces channel interference. So the operator has to optimally decide between paid but better channel quality and free but uncertain channel quality. Also, the operator has to make these decisions without knowing future market variables like customer demand or channel availability. The main contribution of this paper is a deterministic online algorithm for leasing channels that has finite competitive ratio, low time complexity, and that does not rely on the knowledge of market statistics. Such algorithms are desirable in the early stages of the deployment of 3-TSF because the knowledge of market statistics may be rather inaccurate. We use tools from the ski-rental literature to design the online algorithm. The online optimization problem for leasing channels is a novel generalization of the ski-rental problem. We, therefore, make fundamental contributions to the ski-rental literature, the applications of which extend beyond this paper. We also conduct simulations using synthetic traces to compare our online algorithm with the benchmark and state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

To tackle the contradiction between the computation intensive applications and the resource-hungry mobile user equipments (UEs), mobile edge computing (MEC) has been provisioned as a promising solution, which enables the UEs to offload the tasks to the MEC servers. Considering the characteristics of small cell networks (SCNs), integrating MEC into SCNs is natural. But in terms of the high interference, multi-access property, and limited resources of small cell base stations (SBSs), an efficient computation offloading scheme is essential. However, there still lack comprehensive studies on this problem in the densely deployed SCNs. In this paper, we study the energy-efficient computation offloading management scheme in the MEC system with SCNs. The aim of this paper is to minimize the energy consumption of all UEs via jointly optimizing computation offloading decision making, spectrum, power, and computation resource allocation. Specially, the UEs need not only to decide whether to offload but also to determine where to offload. First, we present the computation offloading model and formulate this problem as a mix integer non-linear programming problem, which is NP-hard. Taking advantages of genetic algorithm (GA) and particle swarm optimization (PSO), we design a suboptimal algorithm named as hierarchical GA and PSO-based computation algorithm to solve this problem. Finally, the convergence of this algorithm is studied by simulation, and the performance of the proposed algorithm is verified by comparing with the other baseline algorithms. [ABSTRACT FROM AUTHOR]

Maritime transportation is an important branch of intelligent transportation system (ITS). It is widely recognized that modern ITS technologies and advanced management methods, such as automated yard crane (YC) planning and scheduling, can significantly improve container terminal performance, and also impact the global performance of maritime transportation. In this paper, we investigate two YC scheduling with storage and retrieval tasks in a container block. The main contributions of this paper are: 1) container reshuffling operations and inter-crane interference constraint are both considered and 2) the dynamic processing times for retrieval containers are taken into consideration. These typical YC operation characteristics complicate the YC scheduling, and cause late delivery and economic loss. In this study, we focus on minimizing the maximum tardiness of container task and establishing an integer linear programming model. Regarding the NP-hardness nature of the problem, we develop a heuristic named dividing, sequencing, and comparing (DSC) and a genetic algorithm (GA) based on the characteristics of the problem. The computational results show the efficient performance of the developed algorithms, compared with the exact solutions via Cplex software for small size instances. The efficiency and effectiveness of DSC outperform those of GA for practical size instances. [ABSTRACT FROM AUTHOR]

Implantable closed-loop neural stimulation is desirable for clinical translation and basic neuroscience research. Neural stimulation generates large artifacts at the recording sites, which saturate existing recording front ends. This paper presents a low-power continuous-time delta-sigma analog to digital converter (ADC), which along with an 8 $\times $ gain capacitively-coupled chopper instrumentation amplifier (CCIA), realizes a front end that can digitize neural signals from 1 Hz to 5 kHz in the presence of 200-mVpp differential artifacts and 700-mVpp common-mode (CM) artifacts. A modified loop-filter is used in the ADC along with new linearization techniques to significantly reduce power consumption. Fabricated in 40-nm CMOS, the ADC occupies an area of 0.053 mm2, consumes 4.5 $\mu \text{W}$ from a 1.2-V supply, has an input impedance of 20 $\text{M}\Omega $ and bandwidth (BW) of 5 kHz, and achieves a peak signal to noise and distortion ratio (SNDR) of 93.5 dB for a 1.77- $\text{V}_{\mathrm {pp}}$ differential input at 1 kHz. The ADC’s figure of merit (FOM) (using SNDR) is 184 dB, which is 6 dB higher than the state of the art in high-resolution ADCs. The complete front end occupies an area of 0.113 mm2, consumes 7.3 $\mu \text{W}$ from a 1.2-V supply, has a dc input impedance of 1.5 $\text{G}\Omega $ , input-referred noise of 6.35 $\mu \text{V}_{\mathrm {rms}}$ in 1 Hz–5 kHz, and total harmonic distortion of −81 dB for a 200-mVpp input at 1 kHz, and is immune to 700-mVpp CM interference. Compared to front ends intended for closed-loop neural recording, this paper improves the linear input range by 2 $\times $ , the signal BW by 10 $\times $ , the dynamic range by 12.6 dB, the FOM by 12.4 dB and remains immune to large CM interference while maintaining comparable power, area, and noise performance. [ABSTRACT FROM AUTHOR]

Abstract Methods used to determine the aluminum coating thickness on polymer films may not measure the geometrical thickness directly but may instead measure the mass or other properties, thus leading to different thickness values. Common methods include the determination of evaporation rates using a quartz crystal microbalance (QCM) and the quantitative analysis of dissolved aluminum ions by inductively-coupled plasma mass spectrometry (ICP-MS), which provide mass thickness values. Alternatively, atomic force microscopy (AFM) and interference (INT) across the step of a partially removed aluminum layer yield geometrical values, and optical density (OD) and electrical resistance (ER) measure other properties. We compared the ability of these methods to determine the thickness of aluminum coatings applied to polyethylene terephthalate (PET) and paper by physical vapor deposition. We measured ER using four-point probes, five-point probes, and eddy currents. ER and OD achieved high precision but low accuracy, showing that the resistivity and absorption coefficients of thin aluminum layers can deviate from bulk constants. When the constant values were adjusted, both methods achieved higher accuracy. ICP-MS and QCM values were similar, when a geometrical model was applied, and in comparison AFM and INT showed low precision but high accuracy. When the aluminum was applied to paper instead of PET, only ICP-MS generated reliable results. In summary, the values derived using these different methods are only in agreement when method-specific constants such as absorption coefficients and resistivity are suitably modified. Highlights • Inductively-coupled plasma mass spectrometry is suitable as reference. • Atomic force microscopy and interference achieve low precision but high accuracy. • Electrical resistance and optical density achieve high precision but low accuracy. • Electrical resistivity declines as the aluminum layer gets thicker. • Optical density and resistivity are affected by the substrate under the aluminum. [ABSTRACT FROM AUTHOR]

Faster-than-Nyquist (FTN) transmission employing antenna polarization multiplexing and higher order modulation (HoM) schemes can significantly increase the spectral efficiency (SE) of the existing wireless backhaul links. However, the benefits of each of these SE enhancement techniques come with a price. While FTN introduces inter-symbol interference, a dual-polarized (DP) transmission suffers from cross-polarization interference (XPI), and HoM makes a communication system vulnerable to phase-noise (PN) distortions. In this paper, we investigate, for the first time, a DP-FTN HoM transmission system. We propose a XPI cancellation and PN mitigation structure, coupled with adaptive decision-feedback equalization or linear precoding, to jointly mitigate interference and accomplish carrier-phase tracking. The DP systems combined with the FTN signaling presented in this paper offer more than 150% increase in SE compared with a single-polarized Nyquist transmission. The effectiveness of the proposed algorithms is demonstrated through computer simulations of a coded DP-FTN microwave communication system in the presence of PN. Numerical results suggest that with the proposed interference cancellation methods, a DP-FTN transmission can yield a 3–5.5-dB performance improvement over an equivalent DP-Nyquist system that employs a higher modulation order to achieve the same data rate. [ABSTRACT FROM AUTHOR]

Hardware calibration is essential to restore the uplink/downlink channel reciprocity for multi-user massive multiple-input multiple-output (MIMO) systems operating in a time division duplexing mode. Unfortunately, due to the associated overhead, calibration cannot be performed frequently; furthermore, any calibration procedure leaves behind a residual mismatch between the uplink and downlink channels. In this paper, we study the effects of these calibration errors on the achievable rates in the downlink of a multi-cell, multi-user, and distributed massive MIMO system. Specifically, we develop accurate, yet simple, lower-bounds on the per-user achievable rate, assuming either zero-forcing (ZF) or matched filtering (MF) are used. We also introduce a performance loss coefficient as a measure of sensitivity of the performance to the calibration errors. Using this measure, we identify the conditions under which ZF precoding is more sensitive to calibration errors than MF. Finally, we consider the robust weighted sum-rate maximization problem to mitigate the degrading effects of non-ideal calibration. Our numerical experiments show that the rate lower-bounds developed in this paper accurately quantify the impacts of non-ideal calibration on performance. Also, the proposed robust beamforming scheme improves the average sum-rate by up to 42% compared with the other available schemes. [ABSTRACT FROM AUTHOR]

Cell-free (CF) massive multiple-input multiple-output (MIMO) is an alternative topology for future wireless networks, where a large number of single-antenna access points (APs) are distributed over the coverage area. There are no cells but all users are jointly served by the APs using network MIMO methods. Prior works have claimed that the CF massive MIMO inherits the basic properties of cellular massive MIMO, namely, channel hardening and favorable propagation. In this paper, we evaluate if one can rely on these properties when having a realistic stochastic AP deployment. Our results show that channel hardening only appears in special cases, for example, when the pathloss exponent is small. However, by using 5–10 antennas per AP, instead of one, we can substantially improve the hardening. Only spatially well-separated users will exhibit favorable propagation, but when adding more antennas and/or reducing the pathloss exponent, it becomes more likely for favorable propagation to occur. The conclusion is that we cannot rely on the channel hardening and the favorable propagation when analyzing and designing the CF massive MIMO networks, but we need to use achievable rate expressions and resource allocation schemes that work well also in the absence of these properties. Some options are reviewed in this paper. [ABSTRACT FROM AUTHOR]

In this paper, we characterize the wireless interference of a mobile ad hoc network, where the nodes move according to the random waypoint model. The interferers are assumed to be located within an interference region that is defined as a circular region centered in a fixed node located at a given point of the mobility scenario. The main contribution of this paper is the characterization of the aggregate interference caused to the fixed node by mobile interferers located within the interference region. The distribution of the interference is analyzed taking into account the stochastic nature of the path loss due to the mobility of the nodes, as well as fast fading and shadowing effects. The derivation of the characteristic function of the aggregate interference is used in two different estimators, which successfully characterize the interference using only a small set of samples. The theoretical approach is validated through simulations, which confirm its effectiveness. Finally, we assess the accuracy of the proposed estimators, demonstrating the practical value of this paper. [ABSTRACT FROM AUTHOR]

Numerical optimization has played a central role in addressing key signal processing (SP) problems. Highly effective methods have been developed for a large variety of SP applications such as communications, radar, filter design, and speech and image analytics, just to name a few. However, optimization algorithms often entail considerable complexity, which creates a serious gap between theoretical design/analysis and real-time processing. In this paper, we aim at providing a new learning-based perspective to address this challenging issue. The key idea is to treat the input and output of an SP algorithm as an unknown nonlinear mapping and use a deep neural network (DNN) to approximate it. If the nonlinear mapping can be learned accurately by a DNN of moderate size, then SP tasks can be performed effectively—since passing the input through a DNN only requires a small number of simple operations. In our paper, we first identify a class of optimization algorithms that can be accurately approximated by a fully connected DNN. Second, to demonstrate the effectiveness of the proposed approach, we apply it to approximate a popular interference management algorithm, namely, the WMMSE algorithm. Extensive experiments using both synthetically generated wireless channel data and real DSL channel data have been conducted. It is shown that, in practice, only a small network is sufficient to obtain high approximation accuracy, and DNNs can achieve orders of magnitude speedup in computational time compared to the state-of-the-art interference management algorithm. [ABSTRACT FROM AUTHOR]

This paper analyzes an emerging architecture of cellular network utilizing both planar base stations uniformly distributed in the Euclidean plane and base stations located on roads. An example of this architecture is that where, in addition to conventional planar cellular base stations and users, vehicles also play the role of both base stations and users. A Poisson line process is used to model the road network and, conditionally on the lines, linear Poisson point processes are used to model the vehicles on the roads. The conventional planar base stations and users are modeled by the independent planar Poisson point processes. We use Palm calculus to investigate the statistical properties of a typical user in such a network. Specifically, this paper discusses two different Palm distributions, with respect to the user point processes depending on its type: planar or vehicular. We derive the distance to the nearest base station, the association of the typical users, and the coverage probability of the typical user. Furthermore, we provide a comprehensive characterization of coverage of all possible cellular transmissions in this setting, namely, vehicle-to-vehicle, vehicle-to-infrastructure, infrastructure-to-vehicle, and infrastructure-to-infrastructure. [ABSTRACT FROM AUTHOR]

Caching at base stations (BSs) is a promising approach for supporting the tremendous traffic growth of content delivery over future small-cell wireless networks with limited backhaul. This paper considers exploiting spatial caching diversity (i.e., caching different subsets of popular content files at neighboring BSs) that can greatly improve the cache hit probability, thereby leading to better overall system performance. A key issue in exploiting spatial caching diversity is that the cached content may not be located at the nearest BS, which means that to access such content, a user needs to overcome strong interference from the nearby BSs; this significantly limits the gain of spatial caching diversity. In this paper, we consider a joint design of frequency reuse and caching, such that the benefit of an improved cache hit probability induced by spatial caching diversity and the benefit of interference coordination induced by frequency reuse can be achieved simultaneously. We obtain a closed-form characterization of the approximate successful transmission probability for the proposed scheme and analyze the impact of key operating parameters on the performance. We design a low-complexity algorithm to optimize the frequency reuse factor and the cache storage allocation. Simulations show that the proposed scheme achieves a higher successful transmission probability than existing caching schemes. [ABSTRACT FROM AUTHOR]

Recently, hybrid satellite-terrestrial networks (H-STNs) are expected to support extremely high data rates and exponentially increasing demands of data, which require new spectrum sharing and interference control technology paradigms. By achieving an efficient spectrum sharing among H-STN, traffic offloading is a promising solution for boosting the capacity of traditional cellular networks. In this paper, a software-defined network-based spectrum sharing, and traffic offloading mechanism is proposed to realize the cooperation and competition between the ground base stations (BSs) of the cellular network and beam groups of the satellite-terrestrial communication (STCom) system. Assume that all BSs are operated by the same mobile network operator (MNO). Under the cooperation mode, all the BSs stop occupying a corresponding channel, and a selected beam group of the satellite helps offload the traffic from the BSs by exclusively using this channel. To facilitate the offloading negotiation between the MNO and satellite, we design a second-price auction mechanism which presents positive allocative externalities, i.e., other uncooperative beam groups of the satellite can benefit from the cooperation between BSs and the beam group performing offloading. Meanwhile, the unique optimal biding strategies for different beam groups of the satellite to achieve the symmetric Bayesian equilibrium as well as the expected utility of the MNO are derived and obtained in this paper. The performance of the proposed traffic offloading mechanism is validated in the simulations, which also reveal that there exists the unique optimal offloading threshold for the MNO to achieve the maximum expected utility. [ABSTRACT FROM AUTHOR]

The role of mother tongue in second language learning has been the focus of many discussions and debate among many theorists. It is a popular belief that first language has an effect on the second language acquisition, and it is claimed that L1 can interfere with the acquisition of L2. It is also believed that the role of L1 in the L2 depends on some similarities and differences between the two languages. This research paper aims to summarize some difficulties that second language learners may face to learn English. It has tried to find out factors that play an important role in the acquisition of second language and presents the similarities and differences between the first language and second language acquisition. Furthermore, this paper examines language transfer while learning and teaching EFL, respectively the language interference in the written and spoken English of Albanian students. The analysis of these transfer patterns aims at explaining the written English production by Albanian students, namely, how it is influenced by their mother tongue (Albanian) and what types of changes have taken place in it. [ABSTRACT FROM AUTHOR]

Optical tweezers based on plasmonic nanostructure has a capability of limited and enhanced the light into subwavelength range so that they can manipulate smaller nano molecules such as protein, DNA. In the paper, we present the nanohole structure with an open microcavity can achieve to trap single biomolecules with high efficiency. The simulation results give the optimized structures which the bridge between the two reflective films of the microcavity is formed with ∼1 µm wide by Polydimethylsiloxane (PDMS) chamber. The experimental results show that the nanostructure with microcavity in inverted microscope optical tweezers system can trap effectively protein, DNA, and virus in the larger range than no cavity. The nanostructure presented in the paper has a promising prospect for high efficiently trapping small molecules and detecting biological solution in low concentration. [ABSTRACT FROM AUTHOR]

The paper covers a range of issues related to the specifics of Russian language mastering by Indian students studying in English and Russian. The research is based on an integrative methodological platform that combines approaches to multilingualism formation from the standpoint of psychological linguistics, cognitive linguistics, the theory of language contacts, discourse and communication science. The research involves the techniques of psychological and semantic analyses and verbal associations, the methods of contextual analysis and comparison. The material of the paper is the data obtained from online surveys of Indian students who have been studying at universities in North Ossetia-Alania for six years (elementary and pre-intermediate levels of Russian language proficiency). The study is aimed at identifying perception channels that represent the features of foreign students cognitive style in the Russian natural environment, descripting level-by-level interfering influence of native languages and weak interference of English. Based on text fragments and lexical units, vectors and methods of interlingual interference were demonstrated, its leading types were determined, that are phonetic, phonemic, graphemic, phonemic-graphemic, morphological and lexical. The role of English as a communicative mediator is defined. The analysis done confirmed complex application of auditory, visual and kinesthetic channels at the information input, and revealed the dominance of the auditory perception channel at the information output while learning the Russian language by Indian students. The Indian students cognitive style tends to be simplified through contamination of written and oral speech, compression, abbreviations usage, intensification of associative and semantic links. Strategies for using Internet translation, imitation of mastering the Russian language, literal translation from English into Russian, strategies for the implementation of graphic, phonetic-graphic principles of writing, phonemic and grammatical reduction were identified as the basic communication strategies of Indian students learning Russian.

The paper is devoted to explaining the key cognitive distinctions characteristic to translation process and its teaching. Among them are linguistic interpretation of the input text’s contents, its conceptual adaptation to the accepting culture, etc. To demonstrate them, multiple examples are given to show that translators, particularly not trained enough, often choose for basic translation dominants in the accepting culture those equivalents that are primarily purely linguistic, ignoring conceptual and cultural background of the original and the accepting culture’s notions and forms. Meanwhile, the latter help avoid such translation failures as literal / word by word translation, etc. Special attention in the paper is paid to the translation into the foreign, English, language, its contrastive culture-specific and communicative features as compared to those in the Russian language: to their cognitive dominants in communication and their cross-linguistic asymmetry and in-congruency which generate quite «natural» cross-linguistic interference in Russian-English translation. It is particularly obvious when there are extensive textual nominal ex-pressions, especially terminological, which demonstrate at present an active, extensive and productive usage in English, but present a serious problem in teaching English as a foreign language and translation into it. It is also shown that in Russian their cross-linguistic idiomatic analogues are language specific and show different patterns, but still can be adequately matched with their foreign counter-parts.

Abstract In smart cities, the Internet-of-Thing (IoT) provides an enabling communication infrastructure to support tremendous amount of data exchange. Most IoT applications, e.g., wireless local area network, Bluetooth and so forth, utilize the channel-hopping scheme to suppress the transmission security threats. In this paper, to reduce the mutual interference and external jamming attacks, multiple novel channel-hopping patterns, i.e., traditional no-hit-zone (NHZ) hopping pattern and generalized NHZ hopping pattern, are introduced to suit to IoT networks. Particularly the design of probabilistic hopping pattern is first proposed, which has the various usage probabilities with regard to various channels. The properties of these hopping patterns are investigated by the step-to-step examples. Then, the error-rate performance of the multi-node IoT systems adopting these hopping patterns in the presence of jamming attacks is comprehensively analyzed. The extensive simulations show that the traditional/generalized NHZ hopping patterns are in favor of combating the mutual interference but with the limited capability of reducing jamming attacks, while the probabilistic hopping pattern possesses the opposite feature, that is, it has the predominant merit in suppressing jamming attacks. Thus, the novel channel-hopping pattern-based IoT could provide the secure transmission for communication applications in smart cities. Note that, as the physical-layer security technique, the channel-hopping patterns investigated in this paper are convenient to integrate with the security policies implemented in upper layers (e.g., encryption, authentication and so forth).

This paper investigates the degradation caused by interference resulting from cyclic prefix violation and symbol timing offset in narrowband power line communication systems. In this sense, it presents a unified formulation from which Hermitian symmetric orthogonal frequency division multiplexing (HS-OFDM), orthogonal chirp division multiplexing (OCDM), single-carrier cyclic prefix (SCCP), and orthogonal time–frequency division multiplexing (OTFDM) can be easily derived. The paper then provides closed-form expressions for quantifying the aforementioned interference in the presence of a frequency domain equalizer. The numerical analyses exhibit the performances of these schemes under various data communication conditions, such as the availability of channel state information, the presence or absence of interference, modeling of additive noise as a white or colored Gaussian random process, frequency domain equalizer type, and the use of bit and power allocation techniques. The closed-form expressions and performance analyses regarding achievable data rate and bit error probability provide guidance for dealing with distinct constraints in narrowband power line communication (PLC) systems using the HS-OFDM, OCDM, SCCP, or OTFDM scheme. Lastly, the unified formulation and results obtained motivate the design of multi-scheme transceivers.

Stability is an important issue in order to characterize the performance of a network, and it has become a major topic of study in the last decade. Roughly speaking, a communication network system is said to be stable if the number of packets waiting to be delivered (backlog) is finitely bounded at any one time. In this paper we introduce a number of routing scheduling algorithms which, making use of certain knowledge about the network's structure, guarantee stability for certain injection rates. First, we introduce two new families of combinatorial structures, which we call universally strong selectors and generalized universally strong selectors , that are used to provide a set of transmission schedules. Making use of these structures, we propose two local-knowledge packet-oblivious routing scheduling algorithms. The first proposed routing scheduling algorithm only needs to know some upper bounds on the number of links and on the network's degree, and is asymptotically optimal regarding the injection rate for which stability is guaranteed. The second proposed routing scheduling algorithm is close to be asymptotically optimal, but it only needs to know an upper bound on the number of links. For such algorithms, we also provide some results regarding both the maximum latencies and queue lengths. Furthermore, we also evaluate how the lack of global knowledge about the system topology affects the performance of the routing scheduling algorithms. [ABSTRACT FROM AUTHOR]

Knowing only two high-order statistical moments of modulation symbols, often represented by the fourth moment called “kurtosis”, the overestimation of nonlinear interference (NLI) in a Gaussian noise (GN) model due to Gaussian signaling assumption can be corrected through an enhanced GN (EGN) model. However, in some modern optical communication systems where the transmitted modulation symbols are statistically correlated, such as in systems that use probabilistic constellation shaping (PCS) with finite-length sphere shaping, the kurtosis-based EGN model produces significant inaccuracies in analytical prediction of NLI. In this paper, we show that for correlated modulation symbols, the NLI can be more accurately estimated by substituting a statistical measure called windowed kurtosis into the EGN model, instead of the conventional kurtosis. Remarkably, the optimal window length for windowed kurtosis is found to be consistent with the self-phase modulation (SPM) and cross-phase modulation (XPM) characteristic times in various system configurations. The findings can be used in practice to analytically evaluate and design NLI-tolerant modulation formats. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study of the turbulent structure of the near-field flow of two parallel jets issuing from long round tubes. Measurements were performed for distances between the axes of the tubes , 1.8, and 2.4 and for Reynolds numbers and . It is shown that in the near field of closely spaced twin jets, the longitudinal velocity component on their axis decreases more slowly than in single jets. In this case, the distance between the jets has practically no effect on the transverse scale of the jet and turbulent pulsations of the longitudinal velocity component. Turbulence anisotropy is practically absent throughout the flow field, except in the outer regions of the jets. [ABSTRACT FROM AUTHOR]

Estimating population‐level effects of a vaccine is challenging because there may be interference, that is, the outcome of one individual may depend on the vaccination status of another individual. Partial interference occurs when individuals can be partitioned into groups such that interference occurs only within groups. In the absence of interference, inverse probability weighted (IPW) estimators are commonly used to draw inference about causal effects of an exposure or treatment. Tchetgen Tchetgen and VanderWeele proposed a modified IPW estimator for causal effects in the presence of partial interference. Motivated by a cholera vaccine study in Bangladesh, this paper considers an extension of the Tchetgen Tchetgen and VanderWeele IPW estimator to the setting where the outcome is subject to right censoring using inverse probability of censoring weights (IPCW). Censoring weights are estimated using proportional hazards frailty models. The large sample properties of the IPCW estimators are derived, and simulation studies are presented demonstrating the estimators' performance in finite samples. The methods are then used to analyze data from the cholera vaccine study. [ABSTRACT FROM AUTHOR]

Extremely low-resolution (e.g. one-bit) analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) can substantially reduce hardware cost and power consumption for MIMO radar especially with large scale antennas. In this paper, we focus on the detection performance analysis and joint design for the MIMO radar with one-bit ADCs and DACs. Specifically, under the assumption of low signal-to-noise ratio (SNR) and interference-to-noise ratio (INR), we derive the expressions of probability of detection ($\mathcal {P}_{d}$) and probability of false alarm ($\mathcal {P}_{f}$) for one-bit MIMO radar and also the theoretical performance gap to infinite-bit MIMO radars for the noise-only case. We further find that for a fixed $\mathcal {P}_{f}$ , $\mathcal {P}_{d}$ depends on the defined quantized signal-to-interference-plus-noise ratio (QSINR), which is a function of the transmit waveform and receive filter. Thus, an optimization problem arises naturally to maximize the QSINR by joint designing the waveform and filter. For the formulated problem, we propose an alternating waveform and filter design for QSINR maximization (GREET). At each iteration of GREET, the optimal receive filter is updated via the minimum variance distortionless response (MVDR) method, and due to the difficulty in global optimality, an alternating direction method of multipliers (ADMM) based algorithm is devised to efficiently find a high-quality suboptimal one-bit waveform. Numerical simulations are consistent to the theoretical performance analysis and demonstrate the effectiveness of the proposed design algorithm. [ABSTRACT FROM AUTHOR]

Recently, model-free power control approaches have been developed to achieve the near-optimal performance of cell-free (CF) massive multiple-input multiple-output (MIMO) with affordable computational complexity. In particular, deep reinforcement learning (DRL) is one of such promising techniques for realizing effective power control. In this paper, we propose a model-free method adopting the deep deterministic policy gradient algorithm (DDPG) with feedforward neural networks (NNs) to solve the downlink max-min power control problem in CF massive MIMO systems. Our result shows that compared with the conventional convex optimization algorithm, the proposed DDPG method can effectively strike a performance-complexity trade-off obtaining 1,000 times faster implementation speed and approximately the same achievable user rate as the optimal solution produced by conventional numerical convex optimization solvers, thereby offering effective power control implementations for large-scale systems. Finally, we extend the DDPG algorithm to both the max-sum and the max-product power control problems, while achieving better performance than that achieved by the conventional deep learning algorithm. [ABSTRACT FROM AUTHOR]