Showing papers on "Data transmission published in 2017"
TL;DR: This work exploits the scalability of microresonator-based DKS frequency comb sources for massively parallel optical communications at both the transmitter and the receiver, and demonstrates the potential of these sources to replace the arrays of continuous-wave lasers that are currently used in high-speed communications.
Abstract: Solitons are waveforms that preserve their shape while propagating, as a result of a balance of dispersion and nonlinearity. Soliton-based data transmission schemes were investigated in the 1980s and showed promise as a way of overcoming the limitations imposed by dispersion of optical fibres. However, these approaches were later abandoned in favour of wavelength-division multiplexing schemes, which are easier to implement and offer improved scalability to higher data rates. Here we show that solitons could make a comeback in optical communications, not as a competitor but as a key element of massively parallel wavelength-division multiplexing. Instead of encoding data on the soliton pulse train itself, we use continuous-wave tones of the associated frequency comb as carriers for communication. Dissipative Kerr solitons (DKSs) (solitons that rely on a double balance of parametric gain and cavity loss, as well as dispersion and nonlinearity) are generated as continuously circulating pulses in an integrated silicon nitride microresonator via four-photon interactions mediated by the Kerr nonlinearity, leading to low-noise, spectrally smooth, broadband optical frequency combs. We use two interleaved DKS frequency combs to transmit a data stream of more than 50 terabits per second on 179 individual optical carriers that span the entire telecommunication C and L bands (centred around infrared telecommunication wavelengths of 1.55 micrometres). We also demonstrate coherent detection of a wavelength-division multiplexing data stream by using a pair of DKS frequency combs-one as a multi-wavelength light source at the transmitter and the other as the corresponding local oscillator at the receiver. This approach exploits the scalability of microresonator-based DKS frequency comb sources for massively parallel optical communications at both the transmitter and the receiver. Our results demonstrate the potential of these sources to replace the arrays of continuous-wave lasers that are currently used in high-speed communications. In combination with advanced spatial multiplexing schemes and highly integrated silicon photonic circuits, DKS frequency combs could bring chip-scale petabit-per-second transceivers into reach.
922 citations
TL;DR: This paper provides a comprehensive and exhaustive survey of the state-of-the-art UOWC research in three aspects: 1) channel characterization; 2) modulation; and 3) coding techniques, together with the practical implementations of UowC.
Abstract: Underwater wireless communications refer to data transmission in unguided water environment through wireless carriers, i.e., radio-frequency (RF) wave, acoustic wave, and optical wave. In comparison to RF and acoustic counterparts, underwater optical wireless communication (UOWC) can provide a much higher transmission bandwidth and much higher data rate. Therefore, we focus, in this paper, on the UOWC that employs optical wave as the transmission carrier. In recent years, many potential applications of UOWC systems have been proposed for environmental monitoring, offshore exploration, disaster precaution, and military operations. However, UOWC systems also suffer from severe absorption and scattering introduced by underwater channels. In order to overcome these technical barriers, several new system design approaches, which are different from the conventional terrestrial free-space optical communication, have been explored in recent years. We provide a comprehensive and exhaustive survey of the state-of-the-art UOWC research in three aspects: 1) channel characterization; 2) modulation; and 3) coding techniques, together with the practical implementations of UOWC.
790 citations
TL;DR: A spatial basis expansion model (SBEM) is built to represent the UL/DL channels with far fewer parameter dimensions, which significantly reduces the training overhead and feedback cost and enhances the spectral efficiency.
Abstract: This paper proposes a unified transmission strategy for multiuser time division duplex (TDD)/frequency division duplex (FDD) massive multiple-input–multiple-output (MIMO) systems, including uplink (UL)/downlink (DL) channel estimation and user scheduling for data transmission. With the aid of antenna array theory and array signal processing, we build a spatial basis expansion model (SBEM) to represent the UL/DL channels with far fewer parameter dimensions. Hence, both the UL and DL channel estimations of multiusers can be carried out with a small amount of training resource, which significantly reduces the training overhead and feedback cost. Meanwhile, the pilot contamination problem in the UL training is immediately relieved by exploiting the spatial information of users. To enhance the spectral efficiency, we also design a greedy user scheduling scheme during the data transmission period. Compared with existing low-rank models, the newly proposed SBEM offers an alternative for channel acquisition without the need for channel statistics and can be applied to both TDD and FDD systems. Various numerical results are provided to corroborate the proposed studies.
465 citations
TL;DR: In this article, the authors show how to synthesize the absolute frequency of a lightwave signal, using integrated photonics to implement lasers, system interconnects, and nonlinear frequency comb generation.
Abstract: Integrated-photonics microchips now enable a range of advanced functionalities for high-coherence applications such as data transmission, highly optimized physical sensors, and harnessing quantum states, but with cost, efficiency, and portability much beyond tabletop experiments. Through high-volume semiconductor processing built around advanced materials there exists an opportunity for integrated devices to impact applications cutting across disciplines of basic science and technology. Here we show how to synthesize the absolute frequency of a lightwave signal, using integrated photonics to implement lasers, system interconnects, and nonlinear frequency comb generation. The laser frequency output of our synthesizer is programmed by a microwave clock across 4 THz near 1550 nm with 1 Hz resolution and traceability to the SI second. This is accomplished with a heterogeneously integrated III/V-Si tunable laser, which is guided by dual dissipative-Kerr-soliton frequency combs fabricated on silicon chips. Through out-of-loop measurements of the phase-coherent, microwave-to-optical link, we verify that the fractional-frequency instability of the integrated photonics synthesizer matches the $7.0*10^{-13}$ reference-clock instability for a 1 second acquisition, and constrain any synthesis error to $7.7*10^{-15}$ while stepping the synthesizer across the telecommunication C band. Any application of an optical frequency source would be enabled by the precision optical synthesis presented here. Building on the ubiquitous capability in the microwave domain, our results demonstrate a first path to synthesis with integrated photonics, leveraging low-cost, low-power, and compact features that will be critical for its widespread use.
328 citations
TL;DR: In this paper, an orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated, and a data transmission rate of 11.95 GB/s is achieved with a violet micro-LED.
Abstract: Visible light communication (VLC) is a promising solution to the increasing demands for wireless connectivity. Gallium nitride micro-sized light emitting diodes (micro-LEDs) are strong candidates for VLC due to their high bandwidths. Segmented violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 MHz. An orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated, and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED, when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system. A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.
274 citations
TL;DR: A high-throughput communication approach using the orbital angular momentum (OAM) of acoustic vortex beams with one order enhancement of the data transmission rate at a single frequency is demonstrated.
Abstract: Long-range acoustic communication is crucial to underwater applications such as collection of scientific data from benthic stations, ocean geology, and remote control of off-shore industrial activities. However, the transmission rate of acoustic communication is always limited by the narrow-frequency bandwidth of the acoustic waves because of the large attenuation for high-frequency sound in water. Here, we demonstrate a high-throughput communication approach using the orbital angular momentum (OAM) of acoustic vortex beams with one order enhancement of the data transmission rate at a single frequency. The topological charges of OAM provide intrinsically orthogonal channels, offering a unique ability to multiplex data transmission within a single acoustic beam generated by a transducer array, drastically increasing the information channels and capacity of acoustic communication. A high spectral efficiency of 8.0 ± 0.4 (bit/s)/Hz in acoustic communication has been achieved using topological charges between -4 and +4 without applying other communication modulation techniques. Such OAM is a completely independent degree of freedom which can be readily integrated with other state-of-the-art communication modulation techniques like quadrature amplitude modulation (QAM) and phase-shift keying (PSK). Information multiplexing through OAM opens a dimension for acoustic communication, providing a data transmission rate that is critical for underwater applications.
201 citations
TL;DR: A comprehensive review of various PV monitoring systems is presented for the first time in this paper, which includes the detailed overview of all the major PV monitoring evaluation techniques in terms of their relative performances.
Abstract: The Photovoltaic (PV) monitoring system collects and analyzes number of parameters being measured in a PV plant to monitor and/or evaluate its performance. In order to ensure the reliable and stable operation of any PV system, an effective monitoring system is essential. Moreover, the monitoring system keeps track on various electricity generation indices and fault occurrences. The cost and complexity of existing PV monitoring systems restricts their use to large scale PV plants. Over the past decade, different aspects of PV monitoring systems were reported in wide range of literature. In this paper, a comprehensive review of various PV monitoring systems is presented for the first time. This includes the detailed overview of all the major PV monitoring evaluation techniques in terms of their relative performances. Major aspects of PV monitoring systems which examines in this paper are: sensors and their working principles, controller used in data acquisition systems, data transmission methods, and data storage and analysis. The acquaintance of all these aspects are crucial for the development of effective, low cost, and viable PV monitoring systems for small and medium scale PV plants without compromising on the desired performance.
184 citations
TL;DR: In this article, the authors proposed a resource-allocation solution for the HCRSN to achieve the sustainability of spectrum sensors and conserve the energy of data sensors, which is achieved by two algorithms that operate in tandem: a spectrum sensor scheduling (SSS) algorithm and a data sensor resource allocation (DSRA).
Abstract: The incorporation of cognitive radio (CR) and energy harvesting (EH) capabilities in wireless sensor networks enables spectrum and energy-efficient heterogeneous CR sensor networks (HCRSNs). The new networking paradigm of HCRSNs consists of EH-enabled spectrum sensors and battery-powered data sensors. Spectrum sensors can cooperatively scan the licensed spectrum for available channels, whereas data sensors monitor an area of interest and transmit sensed data to the sink over those channels. In this paper, we propose a resource-allocation solution for the HCRSN to achieve the sustainability of spectrum sensors and conserve the energy of data sensors. The proposed solution is achieved by two algorithms that operate in tandem: a spectrum sensor scheduling (SSS) algorithm and a data sensor resource allocation (DSRA) algorithm. The SSS algorithm allocates channels to spectrum sensors such that the average detected available time for the channels is maximized, while the EH dynamics are considered and primary user (PU) transmissions are protected. The DSRA algorithm allocates the transmission time, power, and channels such that the energy consumption of the data sensors is minimized. Extensive simulation results demonstrate that the energy consumption of the data sensors can be significantly reduced, while maintaining the sustainability of the spectrum sensors.
180 citations
TL;DR: This paper proposes an angle domain hybrid precoding and channel tracking method by exploring the spatial features of the mm-wave massive MIMO channel and results are provided to corroborate the studies.
Abstract: The millimeter-wave (mm-wave) massive multiple-input multiple-output (MIMO) system has gained much attention for its considerable improvement in system throughput. However, the cost of complex hardware, e.g., radio frequency (RF) chains, hinders it from practical deployment. In this paper, we propose an angle domain hybrid precoding and channel tracking method by exploring the spatial features of the mm-wave massive MIMO channel. The number of the effective spatial beams, or equivalently the RF chains, is enormously decreased via the operation of spatial rotation . The users are then scheduled by the angle division multiple access scheme, which groups users according to their direction of arrivals (DOAs). Meanwhile, a channel tracking method is designed for the subsequent data transmission through a small number of pilot symbols. Specifically, the channel information is divided into the DOA information and the gain information, where the DOA information is tracked by a modified unscented Kalman filter and the gain information is estimated from beam training. Numerical results are provided to corroborate our studies.
173 citations
TL;DR: This paper introduces honeypots into the AMI network as a decoy system to detect and gather attack information, and analyzes the interactions between the attackers and the defenders, and derive optimal strategies for both sides.
Abstract: Advanced metering infrastructure (AMI) is an important component for a smart grid system to measure, collect, store, analyze, and operate users consumption data. The need of communication and data transmission between consumers (smart meters) and utilities make AMI vulnerable to various attacks. In this paper, we focus on distributed denial of service attack in the AMI network. We introduce honeypots into the AMI network as a decoy system to detect and gather attack information. We analyze the interactions between the attackers and the defenders, and derive optimal strategies for both sides. We further prove the existence of several Bayesian-Nash equilibriums in the honeypot game. Finally, we evaluate our proposals on an AMI testbed in the smart grid, and the results show that our proposed strategy is effective in improving the efficiency of defense with the deployment of honeypots.
162 citations
01 May 2017
TL;DR: In this article, the authors propose a beam tracking algorithm that extracts information needed to update the steering directions directly from data packets, without the need for spatial scanning during the ongoing data transmission.
Abstract: In order to cope with the severe path loss, millimeter-wave (mm-wave) systems exploit highly directional communication. As a consequence, even a slight beam mis-alignment between two communicating devices (for example, due to mobility) can generate a significant signal drop. This leads to frequent invocations of time-consuming mechanisms for beam re-alignment, which deteriorate system performance. In this paper, we propose smart beam training and tracking strategies for fast mm-wave link establishment and maintenance under node mobility. We leverage the ability of hybrid analog-digital transceivers to collect channel information from multiple spatial directions simultaneously and formulate a probabilistic optimization problem to model the temporal evolution of the mm-wave channel under mobility. In addition, we present for the first time a beam tracking algorithm that extracts information needed to update the steering directions directly from data packets, without the need for spatial scanning during the ongoing data transmission. Simulation results, obtained by a custom simulator based on ray tracing, demonstrate the ability of our beam training/tracking strategies to keep the communication rate only 10% below the optimal bound. Compared to the state of the art, our approach provides a 40% to 150% rate increase, yet requires lower complexity hardware.
TL;DR: The differences between homogeneous and heterogeneous networks regarding APS are discussed, and a two-stage APS method is proposed for hybrid Li-Fi/Wi-Fi networks, which achieves a close-to-optimal throughput at significantly reduced complexity.
Abstract: Hybrid light fidelity (Li-Fi) and wireless fidelity (Wi-Fi) networks are an emerging technology for future indoor wireless communications. This hybrid network combines the high-speed data transmission offered by visible light communication and the ubiquitous coverage of radio-frequency techniques. While a hybrid network can improve the system throughput and users’ experience, it also challenges the process of access point selection (APS) due to the mixture of heterogeneous access points. In this paper, the differences between homogeneous and heterogeneous networks regarding APS are discussed, and a two-stage APS method is proposed for hybrid Li-Fi/Wi-Fi networks. In the first stage, a fuzzy logic system is developed to determine the users that should be connected to Wi-Fi. In the second stage, the remaining users are assigned in the environment of a homogeneous Li-Fi network. Compared with the optimisation method, the proposed method achieves a close-to-optimal throughput at significantly reduced complexity. Simulation results also show that our method greatly improves the system throughput over the conventional methods, such as the signal strength strategy and load balancing, at slightly increased complexity.
Patent•
08 Jun 2017
TL;DR: In this article, the authors present a data transmission method and device, which are to be applied to a source client, wherein the source client is a client in a foreground running status in a mobile terminal, the mobile terminal by means of a split-screen function, divides the display screen thereof into a first split screen for displaying a running interface of the source clients and a second split screen to display a running interfaces of a target clients.
Abstract: Embodiments of the present invention provide a data transmission method and device, which are to be applied to a source client, wherein the source client is a client in a foreground running status in a mobile terminal, the mobile terminal, by means of a split-screen function, divides the display screen thereof into a first split screen for displaying a running interface of the source client and a second split screen for displaying a running interface of a target client, the target client is a client in a foreground running status in the mobile terminal. The method comprises: establishing a communication connection between the source client and the target client; receiving a drag instruction for a thumbnail of target data in the source client and moving the thumbnail according to the drag instruction; monitoring whether a data transmission instruction for the target data is received, if yes, transmitting the target data to the target client through the established communication connection. By applying the embodiments of the present invention, users can make full advantage of the split-screen technology, which simplifies data transmission operation.
TL;DR: This work experimentally demonstrates and characterize the performance of an OAM-multiplexed, free-space optical (FSO) communications link between a ground transmitter and a ground receiver via a moving unmanned-aerial-vehicle (UAV).
Abstract: We explore the use of orbital-angular-momentum (OAM)-multiplexing to increase the capacity of free-space data transmission to moving platforms, with an added potential benefit of decreasing the probability of data intercept. Specifically, we experimentally demonstrate and characterize the performance of an OAM-multiplexed, free-space optical (FSO) communications link between a ground transmitter and a ground receiver via a moving unmanned-aerial-vehicle (UAV). We achieve a total capacity of 80 Gbit/s up to 100-m-roundtrip link by multiplexing 2 OAM beams, each carrying a 40-Gbit/s quadrature-phase-shift-keying (QPSK) signal. Moreover, we investigate for static, hovering, and moving conditions the effects of channel impairments, including: misalignments, propeller-induced airflows, power loss, intermodal crosstalk, and system bit error rate (BER). We find the following: (a) when the UAV hovers in the air, the power on the desired mode fluctuates by 2.1 dB, while the crosstalk to the other mode is -19 dB below the power on the desired mode; and (b) when the UAV moves in the air, the power fluctuation on the desired mode increases to 4.3 dB and the crosstalk to the other mode increases to -10 dB. Furthermore, the channel crosstalk decreases with an increase in OAM mode spacing.
TL;DR: Modified CCS is proposed, which uses two encryption mechanisms, confusion and mask, and performs a much better encryption quality, and can save vast storage space by only storing the matrix generation parameters.
Abstract: Applications of wireless body area networks (WBANs) are extended from remote health care to military, sports, disaster relief, etc. With the network scale expanding, nodes increasing, and links complicated, a WBAN evolves to a body-to-body network. Along with the development, energy saving and data security problems are highlighted. In this paper, chaotic compressive sensing (CCS) is proposed to solve these two crucial problems, simultaneously. Compared with the traditional compressive sensing, CCS can save vast storage space by only storing the matrix generation parameters. Additionally, the sensitivity of chaos can improve the security of data transmission. Aimed at image transmission, modified CCS is proposed, which uses two encryption mechanisms, confusion and mask, and performs a much better encryption quality. Simulation is conducted to verify the feasibility and effectiveness of the proposed methods. The results show that the energy efficiency and security are strongly improved, while the storage space is saved. And the secret key is extremely sensitive, ${\text{10}^{ - \text{15}}}$ perturbation of the secret key could lead to a total different decoding, the relative error is larger than ${100\%}$ . Particularly for image encryption, the performance of the modified method is excellent. The adjacent pixel correlation is smaller than 0.04 in different directions including horizontal, vertical, and diagonal; the entropy of the cipher image with a 256-level gray value is larger than 7.98.
Patent•
16 Jan 2017
TL;DR: In this paper, a beam measurement information of user equipment (UE) is provided to support a higher data transmission rate since 4th generation (4G) communication systems like long-term evolution (LTE).
Abstract: The present disclosure is related to a 5 th generation (5G) or pre-5G communication system to be provided to support a higher data transmission rate since 4 th generation (4G) communication systems like long-term evolution (LTE).A method for generating beam measurement information of user equipment (UE) is provided. The method of UE includes receiving a first reference signal from a base station, requesting a transmission of a second reference signal when a result of measuring the first reference signal satisfies a predetermined condition, receiving the second reference signal, and generating a measurement result based on the second reference signal.
TL;DR: This article addresses the need for random access by the devices to pilot sequences used for channel estimation, and shows that Massive MIMO is a main enabler to achieve fast access with high data rates, and delay-tolerant access with different data rate levels.
Abstract: 5G wireless networks are expected to support new services with stringent requirements on data rates, latency and reliability. One novel feature is the ability to serve a dense crowd of devices, calling for radically new ways of accessing the network. This is the case in machine-type communications, but also in urban environments and hotspots. In those use cases, the high number of devices and the relatively short channel coherence interval do not allow per-device allocation of orthogonal pilot sequences. This article addresses the need for random access by the devices to pilot sequences used for channel estimation, and shows that Massive MIMO is a main enabler to achieve fast access with high data rates, and delay-tolerant access with different data rate levels. Three pilot access protocols along with data transmission protocols are described, fulfilling different requirements of 5G services.
TL;DR: In this article, a multipath cooperative route (MCR) scheme is proposed to facilitate the AR/VR wireless transmissions in 5G small cell networks, in which the delay of the MCR scheme is analytically studied.
Abstract: Augmented and/or virtual reality (AR/VR) are emerging as one of the main applications in future fifth-generation (5G) networks. To meet the requirements of lower latency and massive data transmission in AR/VR applications, a solution with software-defined networking architecture is proposed for 5G small cell networks. On this basis, a multipath cooperative route (MCR) scheme is proposed to facilitate the AR/VR wireless transmissions in 5G small cell networks, in which the delay of the MCR scheme is analytically studied. Furthermore, a service effective energy (SEE) optimization algorithm is developed for AR/VR wireless transmission in 5G small cell networks. Simulation results indicate that both the delay and SEE of the proposed MCR scheme outperform the delay and SEE of the conventional single-path route scheme in 5G small cell networks.
TL;DR: In this paper, the authors demonstrate the feasibility of QKD and classical communication to share the resources of backbone fiber links and thus take the utility of quantum key distribution a great step forward.
Abstract: Quantum key distribution (QKD) generates symmetric keys between two remote parties and guarantees the keys are not accessible to any third party. Wavelength-division multiplexing between QKD and classical optical communications by sharing the existing fiber-optics infrastructure is highly desired in order to reduce the cost of QKD applications. However, comparing to the light for classical transmission, quantum signals are very weak and easily affected by impairments from classical light, such as the spontaneous Raman-scattering effect. Here, by selecting an optimal wavelength of quantum signals, we significantly reduce the influence of the Raman-scattering effect. In addition, through coherent optical communication technology, we achieve high-speed classical data transmission with relatively low launch powers, thereby further reducing the impairments from classical light. As a result, we realize the multiplexing and long-distance copropagation of QKD and terabit classical data transmission up to 80 km. The data capacity is two orders of magnitude larger than the existing results. Our demonstration verifies the feasibility of QKD and classical communication to share the resources of backbone fiber links and thus taking the utility of QKD a great step forward.
Patent•
10 Nov 2017
TL;DR: In this article, a smart contract protection system based on a trusted environment, including a client, block chain nodes, a data provider, a trust environment, a non-trusted environment, smart contract information processing module (A), a block chain node information transmission module (B) (such as a node interaction interface in the Ethereum), an input data transmission module(C), smart contract execution module (D), a local contract information storage pool (E) and a block-chain smart contract storage pool(F).
Abstract: The invention discloses a smart contract protection system based on a trusted environment, including a client, block chain nodes, a data provider, a trusted environment, a non-trusted environment, a smart contract information processing module (A), a block chain node information transmission module (B) (such as a node interaction interface in the Ethereum), an input data transmission module (C), a smart contract execution module (D), a local contract information storage pool (E) and a block chain smart contract storage pool (F). The client is in communication connection with the block chain nodes. The data provider is in communication connection with the block chain nodes. The block chain nodes are in communication connection with one another. The technical problem that the copyright of smart contracts cannot be protected and the rights and interests of smart contract users are damaged due to the fact that the information of smart contracts may easily leak in the existing smart contract system and the technical problem that data may be stolen due to data leakage are solved.
TL;DR: This paper proposes a beam-domain full-duplex (BDFD) massive multiple-input multiple-output (MIMO) scheme to make the CCUD transmission possible and shows that the spectral efficiency gain can even exceed 2 $\times$ in the specific scenarios.
Abstract: Co-time co-frequency uplink and downlink (CCUD) transmission was considered challenging in the cellular system due to the strong self-interference (SI) between the transmitter and receiver of base station (BS). In this paper, by investigating the beam-domain representation of channels based on the basis expansion model, we propose a beam-domain full-duplex (BDFD) massive multiple-input multiple-output (MIMO) scheme to make the CCUD transmission possible. The key idea of the BDFD scheme lies in intelligently scheduling the uplink and downlink user equipment (UE) based on the beam-domain distributions of their associated channels to mitigate SI and enhance transmission efficiency. We show that the BDFD scheme achieves significant savings in uplink/downlink training resource and achieves uplink and downlink sum capacities simultaneously as the number of BS antennas approaches infinity. The superiority of the BDFD scheme over the traditional time-division duplex (TDD)/frequency-division duplex (FDD) massive MIMO is evaluated through simulation for the macrocell environment. The results show that the spectral efficiency gain can even exceed 2 $\times$ in the specific scenarios, since the BDFD scheme utilizes the time-frequency resource more efficiently in both the training and data transmission phases.
TL;DR: The purpose of this paper is to design a set of time-varying state estimators such that the dynamics of the state estimation error satisfies the average H ∞ performance constraints.
TL;DR: In order to minimize the data flow in the MMC, a hierarchical control is proposed where a CCU calculates an identical reference for all the SMs, while the modulation and capacitor voltage balancing is performed in the controller from the SM.
Abstract: Modular multilevel converters (MMC) are penetrating due to their superior performances. Due to the modular structure of the converter, communication platform has to be established between the submodules (SMs) and a central controller unit (CCU). When the communication platform is designed for such an application, several key parameters have to be considered such as high-speed data transfer with low propagation delay, data integrity, and ability for accurate synchronization. In order to minimize the data flow in the MMC, a hierarchical control is proposed where a CCU calculates an identical reference for all the SMs, while the modulation and capacitor voltage balancing is performed in the controller from the SM. Thus, at each sampling instance, only four bytes references are sent by the central controller to the controllers from the SM, while one or two bytes are received from SMs. Furthermore, the control algorithm is validated through experiments.
Patent•
03 May 2017TL;DR: In this paper, beamforming and uplink control and data transmission techniques are described for UE to maintain at least one beam process for operation with multiple beams and/or points, where power, timing, and channel state information may be specific to a beam process.
Abstract: Systems and methods described herein are provided for beamforming and uplink control and data transmission techniques. Such techniques enable a UE to maintain at least one beam process for operation with multiple beams and/or points. A beam process may be indicated for transmission or reception over a downlink or uplink physical channel. Power, timing, and channel state information may be specific to a beam process. A beam process may be established as part of a random access procedure in which resources may be provisioned in random access response messages. Techniques are provided to handle beam process failures, to use beam processes for mobility, and to select beams using open-loop and closed-loop selection procedures.
TL;DR: In this article, the authors presented a methodology of monitoring respiration pattern using piezoelectric transducers incorporating CMOS integrated circuits for signal processing and data transmission, which can be used either as a wearable device itself or alternatively can be attached to a jacket or a chest belt.
Abstract: This paper presents a methodology of monitoring respiration pattern using piezoelectric transducer incorporating CMOS integrated circuits for signal processing and data transmission. As a proof of concept, the system has been tested by placing electrodes on human chest using adhesive hydrogel to detect the pulsatile vibration due to respiration. The system can be used either as a wearable device itself or alternatively can be attached to a jacket or a chest belt. The front-end transducer is a piezoelectric material-based sensor, which is comprised of a ferroelectric polymer named polyvinylidene-fluoride (PVDF). PVDF is also biocompatible, which makes the sensor suitable to be used as a wearable device. The charge produced by the sensor is converted to a proportional voltage signal with the help of a charge amplifier designed in a standard 130-nm CMOS process with eight metal and one poly layer. The analog voltage signal acquired from the charge amplifier is then converted into a digital signal using a reconfigurable pipelined analog-to-digital converter for ease of transmission. An impulse-radio ultra-wideband transmitter operating in the frequency range of 3.1–5 GHz is designed for wireless transmission of the data. The smaller footprint, lighter weight, wireless telemetry, and low-cost material along with the low-power integrated CMOS circuitry for signal processing and data transmission make the proposed system an attractive choice for stable respiration monitoring system.
29 Sep 2017
TL;DR: In this article, a joint pilot assignment and data transmission protocol based on random access is proposed for the uplink of a massive MIMO system, which relies on the averaging across multiple transmission slots of the pilot collision events that result from the random access process.
Abstract: A massive MIMO system, represented by a base station with hundreds of antennas, is capable of spatially multiplexing many devices and thus naturally suited to serve dense crowds of wireless devices in emerging applications, such as machine-type communications. Crowd scenarios pose new challenges in the pilot-based acquisition of channel state information and call for pilot access protocols that match the intermittent pattern of device activity. A joint pilot assignment and data transmission protocol based on random access is proposed in this paper for the uplink of a massive MIMO system. The protocol relies on the averaging across multiple transmission slots of the pilot collision events that result from the random access process. We derive new uplink sum rate expressions that take pilot collisions, intermittent device activity, and interference into account. Simplified bounds are obtained and used to optimize the device activation probability and pilot length. A performance analysis indicates how performance scales as a function of the number of antennas and the transmission slot duration.
TL;DR: A backscatter-assisted wireless powered communication network that includes a hybrid access point and multiple users, including the optimal users’ working mode permutation and time allocation is proposed and simulation results demonstrate the superiority of the proposed model.
Abstract: This paper proposes a backscatter-assisted wireless powered communication network that includes a hybrid access point and multiple users. In conventional wireless powered communication networks with only harvest-then-transmit (HTT) mode, urgent data transmission is not possible since users need to first harvest sufficient energy before transmitting information. Backscatter communication depends on instantaneous excitation energy such that the dedicated time for harvesting energy first is not required. To improve the system performance, both HTT and backscatter modes are employed at the users in the proposed model. An optimization problem is formulated to maximize the sum-throughput by finding the optimal transmission policy, including the optimal users’ working mode permutation and time allocation. Simulation results demonstrate the superiority of the proposed model.
TL;DR: The design of a seamless hybrid wired and wireless interconnection network for multichip systems with dimensions spanning up to tens of centimeters with on-chip wireless transceivers is proposed and it is demonstrated with cycle accurate simulations that such a design increases the bandwidth and reduces the energy consumption in comparison to state-of-the-art wireline I/O based multichIP communication.
Abstract: Computing modules in typical datacenter nodes or server racks consist of several multicore chips either on a board or in a System-in-Package (SiP) environment. State-of-the-art inter-chip communication over wireline channels require data signals to travel from internal nets to the peripheral I/O ports and then get routed over the inter-chip channels to the I/O port of the destination chip. Following this, the data is finally routed from the I/O to internal nets of the destination chip over a wireline interconnect fabric. This multihop communication increases energy consumption while decreasing data bandwidth in a multichip system. Also, traditional I/O does not scale well with technology generations due to limitations of pitch. Moreover, intra-chip and inter-chip communication protocol within such a multichip system is often decoupled to facilitate design flexibility. However, a seamless interconnection between on-chip and off-chip data transfer can improve the communication efficiency significantly. Here, we propose the design of a seamless hybrid wired and wireless interconnection network for multichip systems with dimensions spanning up to tens of centimeters with on-chip wireless transceivers. We demonstrate with cycle accurate simulations that such a design increases the bandwidth and reduces the energy consumption in comparison to state-of-the-art wireline I/O based multichip communication.
TL;DR: A full-passive flexible multigas sensing tag for the determination of oxygen, carbon dioxide, ammonia, and relative humidity readable by a smartphone based on near field communication (NFC) technology for energy harvesting and data transmission to a smartphone.
Abstract: In this work we present a full-passive flexible multigas sensing tag for the determination of oxygen, carbon dioxide, ammonia, and relative humidity readable by a smartphone. This tag is based on near field communication (NFC) technology for energy harvesting and data transmission to a smartphone. The gas sensors show an optic response that is read through high-resolution digital color detectors. A white LED is used as the common optical excitation source for all the sensors. Only a reduced electronics with very low power consumption is required for the reading of the optical responses and data transmission to a remote user. An application for the Android operating system has been developed for the power supplying and data reception from the tag. The responses of the sensors have been calibrated and fitted to simple functions, allowing a fast prediction of the gases concentration. Cross-sensitivity has also been evaluated, finding that in most of the cases it is negligible or easily correctable using the ...
TL;DR: This work proposes and experimentally demonstrates a scheme for pseudo-PDM of four states (PPDM-4) by manipulation of four linearly polarized data channels with the same wavelength, which is expected to open new possibilities to fully explore the use of polarization freedom for capacity and SE improvement over existing fiber systems.
Abstract: Increasing the system capacity and spectral efficiency (SE) per unit bandwidth is one of the ultimate goals for data network designers, especially when using technologies compatible with current embedded fiber infrastructures. Among these, the polarization-division-multiplexing (PDM) scheme, which supports two independent data channels on a single wavelength with orthogonal polarization states, has become a standard one in most state-of-art telecommunication systems. Currently, however, only two polarization states (that is, PDM) can be used, setting a barrier for further SE improvement. Assisted by coherent detection and digital signal processing, we propose and experimentally demonstrate a scheme for pseudo-PDM of four states (PPDM-4) by manipulation of four linearly polarized data channels with the same wavelength. Without any modification of the fiber link, we successfully transmit a 100-Gb s−1 PPDM-4 differential-phase-shift-keying signal over a 150-km single-mode fiber link. Such a method is expected to open new possibilities to fully explore the use of polarization freedom for capacity and SE improvement over existing fiber systems. A scheme for manipulating four linearly polarized data channels down existing fibre optic cables has been developed by researchers in China. Polarization-division multiplexing uses the polarization of light waves to differentiate multiple data streams travelling through a single-mode fibre. Lian-Shan Yan and co-workers from Southwest Jiaotong University have now found a way to accommodate more polarization states at a single wavelength, boosting the potential capacity of data networks. The team implemented a setup that multiplexes four signals having separate 0°, 30°, 90° and 120° polarizations using an optical controller. After transmission, the received signal is analyzed by coherent detectors aligned to the original polarization states, and demultiplexing algorithms. This strategy enabled data to be transferred at 100 Gb s-1 through a 150-km single-mode fibre.