Showing papers on "Data transmission published in 2015"

Massive individual orbital angular momentum channels for multiplexing enabled by Dammann gratings

Abstract: Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods. Orbital angular momentum (OAM) in optical vortex beams offers a new degree of freedom and the potential to increase the capacity of free-space optical communication systems, with OAM beams acting as information carriers for OAM division multiplexing (OAM-DM). We demonstrate independent collinear OAM channel generation, transmission and simultaneous detection using Dammann optical vortex gratings (DOVGs). We achieve 80/160 Tbit s−1 capacity with uniform power distributions along all channels, with 1600 individually modulated quadrature phase-shift keying (QPSK)/16-QAM data channels multiplexed by 10 OAM states, 80 wavelengths and two polarizations. DOVG-enabled OAM multiplexing technology removes the bottleneck of massive OAM state parallel detection and offers an opportunity to raise optical communication systems capacity to Pbit s−1 level. Dammann gratings are used to realize multiplexing based on the generation, transmission and detection of optical angular momentum (OAM). The OAM of optical vortex beams offers a new degree of freedom for multiplexing and hence the promise of higher data communication rates, but massive parallel detection of OAM states has proved challenging. Now, researchers in China, Australia and Singapore have used Dammann optical vortex gratings (DOVGs) to realize multiplexing of massive OAM channels with individual modulation and simultaneous detection capabilities. They achieved a data capacity of 80 Tbit s−1 by multiplexing 1600 channels using ten OAM states, 80 wavelengths and two polarizations. This DOVG-enabled OAM multiplexing technology removes the bottleneck of massive parallel detection of OAM states and has the potential to increase optical communication capacities to the Pbit s−1 level.

A Minimally Invasive 64-Channel Wireless μECoG Implant

Abstract: Emerging applications in brain–machine interface systems require high-resolution, chronic multisite cortical recordings, which cannot be obtained with existing technologies due to high power consumption, high invasiveness, or inability to transmit data wirelessly. In this paper, we describe a microsystem based on electrocorticography (ECoG) that overcomes these difficulties, enabling chronic recording and wireless transmission of neural signals from the surface of the cerebral cortex. The device is comprised of a highly flexible, high-density, polymer-based 64-channel electrode array and a flexible antenna, bonded to 2.4 mm × 2.4 mm CMOS integrated circuit (IC) that performs 64-channel acquisition, wireless power and data transmission. The IC digitizes the signal from each electrode at 1 kS/s with 1.2 μV input referred noise, and transmits the serialized data using a 1 Mb/s backscattering modulator. A dual-mode power-receiving rectifier reduces data-dependent supply ripple, enabling the integration of small decoupling capacitors on chip and eliminating the need for external components. Design techniques in the wireless and baseband circuits result in over 16× reduction in die area with a simultaneous 3× improvement in power efficiency over the state of the art. The IC consumes 225 μW and can be powered by an external reader transmitting 12 mW at 300 MHz, which is over 3× lower than IEEE and FCC regulations.

On the Design of a Solar-Panel Receiver for Optical Wireless Communications With Simultaneous Energy Harvesting

Abstract: This paper proposes a novel design of an optical wireless communications (OWC) receiver using a solar panel as a photodetector. The proposed system is capable of simultaneous data transmission and energy harvesting. The solar panel can convert a modulated light signal into an electrical signal without any external power requirements. Furthermore, the direct current (DC) component of the modulated light can be harvested in the proposed receiver. The generated energy can potentially be used to power a user terminal or at least to prolong its operation time. The current work discusses the various parameters which need to be considered in the design of a system using a solar panel for simultaneous communication and energy harvesting. The presented theory is supported with an experimental implementation of orthogonal frequency division multiplexing (OFDM), thus, proving the validity of the analysis and demonstrating the feasibility of the proposed receiver. Using the propounded system, a communication link with a data rate of 11.84 Mbps is established for a received optical signal with a peak-to-peak amplitude of $\hbox{0.7}\times \hbox{10}^{-3}\ \hbox{W}/\hbox{cm}^{2}$ .

Method and apparatus for high bandwidth data transmission in content-based networks

Abstract: Methods and apparatus for delivering data over extant infrastructure within a content-based network. In one embodiment, the network comprises a cable network, and the infrastructure comprises that nominally used for on-demand (OD) services such as VOD. The method includes the allocation of dedicated end-to-end network resources via a “session request, as well as data flow control and packet size adaptation, by a data server based on feedback from the requesting/receiving client device (e.g., DSTB) within the network. Mechanisms for retransmission requests for error recovery are also provided.

Otfs methods of data channel characterization and uses thereof

Abstract: Fiber, cable, and wireless data channels are typically impaired by reflectors and other imperfections, producing a channel state with echoes and frequency shifts in data waveforms. Here, methods of using OTFS pilot symbol waveform bursts to automatically produce a detailed 2D model of the channel state are presented. This 2D channel state can then be used to optimize data transmission. For wireless data channels, an even more detailed 2D model of channel state can be produced by using polarization and multiple antennas in the process. Once 2D channel states are known, the system turns imperfect data channels from a liability to an advantage by using channel imperfections to boost data transmission rates. The methods can be used to improve legacy data transmission modes in multiple types of media, and are particularly useful for producing new types of robust and high capacity wireless communications using non-legacy OTFS data transmission methods.

Wireless Power and Data Transfer via a Common Inductive Link Using Frequency Division Multiplexing

Abstract: For wireless power transfer (WPT) systems, communication between the primary side and the pickup side is a challenge because of the large air gap and magnetic interferences. A novel method, which integrates bidirectional data communication into a high-power WPT system, is proposed in this paper. The power and data transfer share the same inductive link between coreless coils. Power/data frequency division multiplexing technique is applied, and the power and data are transmitted by employing different frequency carriers and controlled independently. The circuit model of the multiband system is provided to analyze the transmission gain of the communication channel, as well as the power delivery performance. The crosstalk interference between two carriers is discussed. In addition, the signal-to-noise ratios of the channels are also estimated, which gives a guideline for the design of mod/demod circuits. Finally, a 500-W WPT prototype has been built to demonstrate the effectiveness of the proposed WPT system.

Laissez-Faire: Fully Asymmetric Backscatter Communication

Abstract: Backscatter provides dual-benefits of energy harvesting and low-power communication, making it attractive to a broad class of wireless sensors. But the design of a protocol that enables extremely power-efficient radios for harvesting-based sensors as well as high-rate data transfer for data-rich sensors presents a conundrum. In this paper, we present a new {\em fully asymmetric} backscatter communication protocol where nodes blindly transmit data as and when they sense. This model enables fully flexible node designs, from extraordinarily power-efficient backscatter radios that consume barely a few micro-watts to high-throughput radios that can stream at hundreds of Kbps while consuming a paltry tens of micro-watts. The challenge, however, lies in decoding concurrent streams at the reader, which we achieve using a novel combination of time-domain separation of interleaved signal edges, and phase-domain separation of colliding transmissions. We provide an implementation of our protocol, LF-Backscatter, and show that it can achieve an order of magnitude or more improvement in throughput, latency and power over state-of-art alternatives.

Distortion-Aware Concurrent Multipath Transfer for Mobile Video Streaming in Heterogeneous Wireless Networks

Abstract: The massive proliferation of wireless infrastructures with complementary characteristics prompts the bandwidth aggregation for Concurrent Multipath Transfer (CMT) over heterogeneous access networks. Stream Control Transmission Protocol (SCTP) is the standard transport-layer solution to enable CMT in multihomed communication environments. However, delivering high-quality streaming video with the existing CMT solutions still remains problematic due to the stringent quality of service (QoS) requirements and path asymmetry in heterogeneous wireless networks. In this paper, we advance the state of the art by introducing video distortion into the decision process of multipath data transfer. The proposed distortion-aware concurrent multipath transfer (CMT-DA) solution includes three phases: 1) per-path status estimation and congestion control; 2) quality-optimal video flow rate allocation; 3) delay and loss controlled data retransmission. The term ‘flow rate allocation’ indicates dynamically picking appropriate access networks and assigning the transmission rates. We analytically formulate the data distribution over multiple communication paths to minimize the end-to-end video distortion and derive the solution based on the utility maximization theory. The performance of the proposed CMT-DA is evaluated through extensive semi-physical emulations in Exata involving H.264 video streaming. Experimental results show that CMT-DA outperforms the reference schemes in terms of video peak signal-to-noise ratio (PSNR), goodput, and inter-packet delay.

Hybrid Random Access and Data Transmission Protocol for Machine-to-Machine Communications in Cellular Networks

Abstract: To address random access channel (RACH) congestion and high signaling overhead problems of machine-to-machine (M2M) communication in cellular networks, we propose a new design of a random access procedure that is exclusively engineered for the M2M communication. Our design has two prominent features. One is a fast signaling process that allows M2M user equipment to transmit data right after preamble transmission on a physical RACH to reduce the signaling overhead. The other is a self-optimization feature that allows the cellular system to produce optimal M2M throughput by adaptively changing resource block (RB) composition and an access barring parameter according to the amount of available RBs and the M2M traffic load. We derive a closed-form analytic formula for the M2M traffic throughput and propose a joint adaptive resource allocation and access barring scheme based on the analytic results. By simulation, we show that the proposed scheme exhibits a near-optimal performance in terms of the capacity.

64 Gbit/s Transmission over 850 m Fixed Wireless Link at 240 GHz Carrier Frequency

Abstract: A directive fixed wireless link operating at a center frequency of 240 GHz achieves a data rate of 64 Gbit/s over a transmission distance of 850 m using QPSK and 8PSK modulation, in a single-channel approach without the use of spatial diversity concepts. The analog transmit and receive frontend consists of active monolithic integrated circuits including broadband RF amplification and quadrature subharmonic mixer channels. The analog frontend is addressed by 64 GSa/s ADC and DAC boards, which are amenable to real-time data transmission. A link budget calculation allows for the estimation of the performance under adverse weather conditions.

Full-Duplex Cognitive Radio: A New Design Paradigm for Enhancing Spectrum Usage

Abstract: With the rapid growth of demand for ever-increasing data rate, spectrum resources have become more and more scarce. As a promising technique to increase the efficiency of the spectrum utilization, cognitive radio (CR) technique has the great potential to meet such a requirement by allowing un-licensed users to coexist in licensed bands. In conventional CR systems, the spectrum sensing is performed at the beginning of each time slot before the data transmission. This unfortunately results in two major problems: 1) transmission time reduction due to sensing, and 2) sensing accuracy impairment due to data transmission. To tackle these problems, in this paper we present a new design paradigm for future CR by exploring the full-duplex (FD) techniques to achieve the simultaneous spectrum sensing and data transmission. With FD radios equipped at the secondary users (SUs), SUs can simultaneously sense and access the vacant spectrum, and thus, significantly improve sensing performances and meanwhile increase data transmission efficiency. The aim of this article is to transform the promising conceptual framework into the practical wireless network design by addressing a diverse set of challenges such as protocol design and theoretical analysis. Several application scenarios with FD enabled CR are elaborated, and key open research directions and novel algorithms in these systems are discussed.

Towards MMIC-Based 300GHz Indoor Wireless Communication Systems

Abstract: SUMMARY This contribution presents a full MMIC chip set, transmit and receive RF frontend and data transmission experiments at a carrier frequency of 300GHz and with data rates of up to 64Gbit/s. The radio is dedicated to future high data rate indoor wireless communication, serving application scenarios such as smart offices, data centers and home theaters. The paper reviews the underlying high speed transistor and MMIC process, the performance of the quadrature transmitter and receiver, as well as the local oscillator generation by means of frequency multiplication. Initial transmission experiments in a single-input single-output setup and zero-IF transmit and receive scheme achieve up to 64Gbit/s data rates with QPSK modulation. The paper discusses the current performance limitations of the RF frontend and will outline paths for improvements in view of achieving 100Gbit/s capability.

Full duplex cognitive radio: a new design paradigm for enhancing spectrum usage

Abstract: With the rapid growth of demand for ever increasing data rates, spectrum resources have become more and more scarce. As a promising technique to increase the efficiency of the spectrum utilization, cognitive radio has great potential to meet such a requirement by allowing unlicensed users to coexist in licensed bands. In conventional CR systems, spectrum sensing is performed at the beginning of each time slot before data transmission. Unfortunately, this results in two major problems: transmission time reduction due to sensing, and sensing accuracy impairment due to data transmission. To tackle these problems, in this article we present a new design paradigm for future CR by exploring full duplex techniques to achieve simultaneous spectrum sensing and data transmission. With FD radios equipped at secondary users (SUs), the SUs can simultaneously sense and access the vacant spectrum, and thus significantly improve sensing performance while increasing data transmission efficiency. The aim of this article is to transform the promising conceptual framework into a practical wireless network design by addressing a diverse set of challenges such as protocol design and theoretical analysis. Several application scenarios with FD-enabled CR are elaborated, and key open research directions and novel algorithms in these systems are discussed.

Exploring IOT Application Using Raspberry Pi

Abstract: There are thousands of sensors in an industry with different usage, such as, pressure transmitters, flow meter, temperature transmitters, level transmitters, and so on. Wired networks are mainly used to transfer data to base station by connecting sensor. It brings advantage as it provides reliable and stable communication system for instruments and controls. However, the cost of cables necessary is very costly. Therefore, recently low cost wireless networks are strongly required by customers, for example, temporary instrument networks and/or some non-critical permanent sites which require low data rate and longer battery life. In client/server model, file server act as a parent's node which allow multiple child node to connect with it. It is responsible for central storage and data management so that other computers enable to access the file under the same network. This article explores the use of Raspberry Pi to function as a server in which several laptops are connected to it to copy, store and delete the file over network. IT requires authentication for user login before granting access to the file to ensure data integrity and security. File server is widely used in many areas, for example in education for uploading study note into the serve and student immediate downloading it into their computer. Moreover this work also explores the use of Raspberry Pi B+ model and XBee (ZigBee module) to demonstrate wireless communication data transmission, proving the validity of usage as a mobile low-power wireless network communication. The main goal of the research is to explore the use of Raspberry Pi for client-server communication using various wireless communication scenario such as Wi-Fi and ZigBee.

Convolution engine: balancing efficiency and flexibility in specialized computing

Abstract: General-purpose processors, while tremendously versatile, pay a huge cost for their flexibility by wasting over 99% of the energy in programmability overheads. We observe that reducing this waste requires tuning data storage and compute structures and their connectivity to the data-flow and data-locality patterns in the algorithms. Hence, by backing off from full programmability and instead targeting key data-flow patterns used in a domain, we can create efficient engines that can be programmed and reused across a wide range of applications within that domain.We present the Convolution Engine (CE)---a programmable processor specialized for the convolution-like data-flow prevalent in computational photography, computer vision, and video processing. The CE achieves energy efficiency by capturing data-reuse patterns, eliminating data transfer overheads, and enabling a large number of operations per memory access. We demonstrate that the CE is within a factor of 2--3× of the energy and area efficiency of custom units optimized for a single kernel. The CE improves energy and area efficiency by 8--15× over data-parallel Single Instruction Multiple Data (SIMD) engines for most image processing applications.

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review.

Abstract: The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1) describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2) present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3) compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4) summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation.

Hybrid Analog-Digital Channel Estimation and Beamforming: Training-Throughput Tradeoff

Abstract: This paper develops hybrid analog-digital channel estimation and beamforming techniques for multiuser massive multiple-input multiple-output (MIMO) systems with limited number of radio frequency (RF) chains. For these systems, first, we design novel minimum-mean-squared error (MMSE) hybrid analog-digital channel estimator by considering both cases with perfect and imperfect channel covariance matrix knowledge. Then, we utilize the estimated channels to enable beamforming for data transmission. When the channel covariance matrices of all user equipments (UEs) are known perfectly, we show that there is a tradeoff between the training duration and throughput. Specifically, we exploit the fact that the optimal training duration that maximizes the throughput depends on the covariance matrices of all UEs, number of RF chains, and channel coherence time ( $T_c$ ). We also show that the training time optimization problem can be formulated as a concave maximization problem where its global optimal solution can be obtained efficiently using existing tools. The analytical expressions are validated by performing extensive Monte Carlo simulations.

Self-Triggered Communication Enabled Control of Distributed Generation in Microgrids

Abstract: Efficient utilization of distributed generation (DG) resources in a microgrid requires coordinated control, which can be realized using multiagent-based system model. The coordinated control requires information exchange among the distributed agents, which can be implemented using either periodic or need-based aperiodic data transmission. For reducing the data communication requirements among the agents, an aperiodic self-triggered communication-based coordinated control is proposed. Centralized as well as distributed self-triggered coordinated control is implemented. The performance evaluation results show that self-triggered aperiodic communication requires lower data rates, while delivering the same performance as that of periodic sampled data control.

Communication system, a communication method, and a communication apparatus

Abstract: A communication system for carrying out data communication among a plurality of communication stations is disclosed in which a first communication station for transmitting to other communication stations a Request To Send (RTS) signal for requesting a transmission upon the start of the data transmission; and a plurality of second communication stations transmitting to other communication stations a Clear To Send (CTS) signal for notifying the completion of preparing the reception, wherein the first communication station transmits the RTS signal describing at least each of addresses the second communication stations that are desired to receive the data, and receives a plurality of CTS signals transmitted from each of the second communication stations in order to increase communication capacity

Energy Efficient Clustering Algorithms in Wireless Sensor Networks: A Survey

Abstract: To maximize network lifetime in Wireless Sensor Networks (WSNs) the paths for data transfer are selected in such a way that the total energy consumed along the path is minimized To support high scalability and better data aggregation, sensor nodes are often grouped into disjoint, non overlapping subsets called clusters Clusters create hierarchical WSNs which incorporate efficient utilization of limited resources of sensor nodes and thus extends network lifetime The objective of this paper is to present a state of the art survey on clustering algorithms reported in the literature of WSNs Our paper presents a taxonomy of energy effi cient clustering algorithms in WSNs And also present timeline and description of LEACH and Its descendant in WSNs

Experimental demonstration of large capacity WSDM optical access network with multicore fibers and advanced modulation formats

Abstract: Towards the next generation optical access network supporting large capacity data transmission to enormous number of users covering a wider area, we proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers with advanced modulation formats As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers with 587km distance As a cost-effective modulation scheme for access network, the optical OFDM-QPSK signal has been intensity modulated on the downstream transmission in the optical line terminal (OLT) and it was directly detected in the optical network unit (ONU) after MCF transmission 10 wavelengths with 25GHz channel spacing from an optical comb generator are employed and each wavelength is loaded with 5Gb/s OFDM-QPSK signal After amplification, power splitting, and fan-in multiplexer, 10-wavelength downstream signal was injected into six outer layer cores simultaneously and the aggregation downstream capacity reaches 300 Gb/s −16 dBm sensitivity has been achieved for 38 × 10−3 bit error ratio (BER) with 7% Forward Error Correction (FEC) limit for all wavelengths in every core Upstream signal from ONU side has also been generated and the bidirectional transmission in the same core causes negligible performance degradation to the downstream signal As a universal platform for wired/wireless data access, our proposed architecture provides additional dimension for high speed mobile signal transmission and we hence demonstrated an upstream delivery of 20Gb/s per wavelength with QPSK modulation formats using the inner core of MCF emulating a mobile backhaul service The IQ modulated data was coherently detected in the OLT side −19 dBm sensitivity has been achieved under the FEC limit and more than 18 dB power budget is guaranteed

Visible light communications towards 5G

Abstract: 5G networks have to offer extremely high capacity for novel streaming applications. One of the most promising approaches is to embed large numbers of cooperating small cells into the macro-cell coverage area. Alternatively, optical wireless based technologies can be adopted as an alternative physical layer offering higher data rates. Visible light communications (VLC) is an emerging technology for future high capacity communication links (it has been accepted to 5GPP) in the visible range of the electromagnetic spectrum (~370–780 nm) utilizing light-emitting diodes (LEDs) simultaneously provide data transmission and room illumination. A major challenge in VLC is the LED modulation bandwidths, which are limited to a few MHz. However, myriad gigabit speed transmission links have already been demonstrated. Non line-of-sight (NLOS) optical wireless is resistant to blocking by people and obstacles and is capable of adapting its’ throughput according to the current channel state information. Concurrently, organic polymer LEDs (PLEDs) have become the focus of enormous attention for solid-state lighting applications due to their advantages over conventional white LEDs such as ultra-low costs, low heating temperature, mechanical flexibility and large photoactive areas when produced with wet processing methods. This paper discusses development of such VLC links with a view to implementing ubiquitous broadcasting networks featuring advanced modulation formats such as orthogonal frequency division multiplexing (OFDM) or carrier-less amplitude and phase modulation (CAP) in conjunction with equalization techniques. Finally, this paper will also summarize the results of the European project ICT COST IC1101 OPTICWISE (Optical Wireless Communications - An Emerging Technology) dealing VLC and OLEDs towards 5G networks.

Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations

Abstract: Quantum key distribution (QKD) has the potential to improve communications security by offering cryptographic keys whose security relies on the fundamental properties of quantum physics. The use of a trusted quantum receiver on an orbiting satellite is the most practical near-term solution to the challenge of achieving long-distance (global-scale) QKD, currently limited to a few hundred kilometers on the ground. This scenario presents unique challenges, such as high photon losses and restricted classical data transmission and processing power due to the limitations of a typical satellite platform. Here we demonstrate the feasibility of such a system by implementing a QKD protocol, with optical transmission and full post-processing, in the high-loss regime using minimized computing hardware at the receiver. Employing weak coherent pulses with decoy states, we demonstrate the production of secure key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility of a satellite uplink by generating secure key while experimentally emulating the varying channel losses predicted for realistic low-Earth-orbit satellite passes at 600 km altitude. With a 76 MHz source and including finite-size analysis, we extract 3374 bits of secure key from the best pass. We also illustrate the potential benefit of combining multiple passes together: while one suboptimal "upper-quartile" pass produces no finite-sized key with our source, the combination of three such passes allows us to extract 165 bits of secure key. Alternatively, we find that by increasing the signal rate to 300 MHz it would be possible to extract 21570 bits of secure finite-sized key in just a single upper-quartile pass.

Ground station network optimization for space-to-ground optical communication links

Abstract: Space-to-ground optical data links enable higher data rates, require less electrical power, and allow more compact system designs than their corresponding RF counterparts. They may be applied to, for example, downlink Earth observation data from low Earth orbit satellites, or as so-called feeder links for data transmission to geostationary telecommunication or multimedia satellites. However, optical space-to-ground links suffer from limited availability due to cloud blockage. The application of optical ground station (OGS) diversity and thus a network of OGS is required to overcome this limitation. In this paper, we report on OGS networks and the calculation of combined network availabilities. Five years of cloud data gathered by a Meteostat Second Generation satellite have been evaluated. Single- and joint-site statistics as well as correlation between OGS sites are introduced. In order to effectively reduce computational effort, a network optimization method, exploiting the correlation between sites and single-site availabilities, is proposed. Furthermore, the cloud data are used to find several optimal OGS networks and to simulate the networks' availabilities and temporal behaviors. Optimal German, European, and intercontinental networks are identified. With the increasing number of stations, the German network converges to an availability of 84.7%, and the European network to around 99.9%. The intercontinental network even reached an availability of 100% for nine or more stations during the considered time span.

Data transmission method, base station, and terminal

Abstract: A data transmission method is provided The method includes obtaining configuration information, wherein the configuration information indicates transmission resources of a random access preamble and payload data corresponding to the random access preamble, transmitting the random access preamble and the payload data at the transmission resources, modulating the payload data using a modulation scheme supporting asynchronous transmission, and receiving feedback information, wherein the feedback information comprises an indication which indicates whether the payload data is successfully received Various examples of the present disclosure also describe a method for receiving data with space multiplexing which is applied to a base station side, and further describe a terminal and a base station Employing the examples of the present disclosure, transmission efficiency of long duty cycle and sporadic small data packets of a large number of devices in the Internet of Things in future communication systems can be improved

Balance transmission mechanism in underwater acoustic sensor networks

Abstract: With the rapid development of underwater acoustic modem technology, underwater acoustic sensor networks (UWASNs) have more applications in long-term monitoring of the deployment area. In the underwater environment, the sensors are costly with limited energy. And acoustic communication medium poses new challenges, including high path loss, low bandwidth, and high energy consumption. Therefore, designing transmission mechanism to decrease energy consumption and to optimize the lifetime of UWASN becomes a significant task. This paper proposes a balance transmission mechanism, and divides the data transmission process into two phases. In the routing set-up phase, an efficient routing algorithm based on the optimum transmission distance is present to optimize the energy consumption of the UWASN. And then, a data balance transmission algorithm is introduced in the stable data transmission phase. The algorithm determines one-hop or multihop data transmission of the node to underwater sink according to the current energy level of adjacent nodes. Furthermore, detailed theoretical analysis evaluates the optimum energy levels in the UWASNs with different scales. The simulation results prove the efficiency of the BTM.

LAST: A Framework to Localize, Access, Schedule, and Transmit in Indoor VLC Systems

Abstract: The need allowing indoor access to the Internet services requires to reduce the electromagnetic pollution. Recently, the scientific community is looking for alternatives to the use of radio frequency communication, leading to propose and study the new paradigm of visible light communications. In order to present a system implementing transmission and access procedures, we propose a logical stream starting from user localization, so as to decide which LEDs can provide access, thus basically performing a space-division multiple access by scheduling data on the basis of the bits to be transmitted. For this aim, a two-bands access scheme is proposed, and implemented through the use of a separated channel where signaling specifies where, in the wavelength domain, the reception must be operated by the different users. A multiple-input multiple-output scheme is considered for data transmission, in order to increase rate with a reliable error rate performance. Performance is evaluated for what concerns localization and access tasks, so as to show the effectiveness of the proposed scheme. Performance comparison with the recent literature has been also reported.

ZigBee-Based Communication System for Data Transfer Within Future Microgrids

Abstract: A wireless data communication system for future microgrids (MGs) is presented in this paper. It is assumed that each MG has a central controller and each distributed generation unit in the MG has a local controller. The communication system is responsible for transmitting and receiving data amongst these controllers. This communication system is based on ZigBee technology, which is a low cost and low power consumption device. However, its main limitation is the low data transfer rate. To reduce the number of data transactions, a data management scheme is presented in this paper. The required data to be transferred are defined and a suitable coding is proposed. Finally, the number of transmitted symbols and the processing time of the proposed data management scheme are numerically analyzed. In addition, the dynamic operation of an MG is evaluated considering the delays that are imposed by this communication system.

Method for transmitting and receiving downlink control information in wireless communication system supporting device-to-device communication and device therefor

Abstract: A method of transmitting and receiving downlink control information in a wireless communication system that supports communication between terminals and a device for the same are provided. Specifically, a method of receiving downlink control information in a wireless communication system that supports Device-to-Device (D2D) communication includes: receiving, by a terminal, downlink control information for D2D communication from a base station, wherein the downlink control information includes a Physical Sidelink Shared Channel (PSSCH) resource allocation information for D2D data transmission, and a Physical Sidelink Control Channel (PSCCH) resource for D2D control information transmission is derived from the PSSCH resource allocation information.