scispace - formally typeset
Search or ask a question

Showing papers on "Data transmission published in 2014"


Journal ArticleDOI
TL;DR: In this article, the authors demonstrate the viability of spatial multiplexing to reach a data rate of 5.1 Tbit/s−1/carrier−1 on a single wavelength over a single fiber, by employing few-mode multicore fiber, compact three-dimensional waveguide multiplexers and energy-efficient frequency-domain MIMO equalization.
Abstract: Single-mode fibres with low loss and a large transmission bandwidth are a key enabler for long-haul high-speed optical communication and form the backbone of our information-driven society. However, we are on the verge of reaching the fundamental limit of single-mode fibre transmission capacity. Therefore, a new means to increase the transmission capacity of optical fibre is essential to avoid a capacity crunch. Here, by employing few-mode multicore fibre, compact three-dimensional waveguide multiplexers and energy-efficient frequency-domain multiple-input multiple-output equalization, we demonstrate the viability of spatial multiplexing to reach a data rate of 5.1 Tbit s−1 carrier−1 (net 4 Tbit s−1 carrier−1) on a single wavelength over a single fibre. Furthermore, by combining this approach with wavelength division multiplexing with 50 wavelength carriers on a dense 50 GHz grid, a gross transmission throughput of 255 Tbit s−1 (net 200 Tbit s−1) over a 1 km fibre link is achieved. A few-mode, multicore fibre allows ultra-high-speed data transmission on a single wavelength of light.

426 citations


Journal ArticleDOI
TL;DR: Characteristics unique to image-sensor-based VLC as compared to radio wave technology are identified to improve automotive safety and demonstrate its effectiveness through a V2V communication field trial.
Abstract: The present article introduces VLC for automotive applications using an image sensor. In particular, V2I-VLC and V2V-VLC are presented. While previous studies have documented the effectiveness of V2I and V2V communication using radio technology in terms of improving automotive safety, in the present article, we identify characteristics unique to image-sensor-based VLC as compared to radio wave technology. The two primary advantages of a VLC system are its line-of-sight feature and an image sensor that not only provides VLC functions, but also the potential vehicle safety applications made possible by image and video processing. Herein, we present two ongoing image-sensor-based V2I-VLC and V2VVLC projects. In the first, a transmitter using an LED array (which is assumed to be an LED traffic light) and a receiver using a high-framerate CMOS image sensor camera is introduced as a potential V2I-VLC system. For this system, real-time transmission of the audio signal has been confirmed through a field trial. In the second project, we introduce a newly developed CMOS image sensor capable of receiving highspeed optical signals and demonstrate its effectiveness through a V2V communication field trial. In experiments, due to the high-speed signal reception capability of the camera receiver using the developed image sensor, a data transmission rate of 10 Mb/s has been achieved, and image (320 × 240, color) reception has been confirmed together with simultaneous reception of various internal vehicle data, such as vehicle ID and speed.

340 citations


Book
01 Jan 2014
TL;DR: In this article, the authors present a detailed analysis of the satellite link performance with respect to different types of satellite links, including transparent satellite, regenerative satellite, and multibeam antenna coverage vs moonbeam coverage.
Abstract: ACKNOWLEDGEMENT ACRONYMS NOTATION 1 INTRODUCTION 11 Birth of satellite communications 12 Development of satellite communications 13 Configuration of a satellite communications system 14 Types of orbit 15 Radio regulations 16 Technology trends 17 Services 18 The way forward References 2 ORBITS AND RELATED ISSUES 21 Keplerian orbits 22 Useful orbits for satellite communication 23 Perturbations of orbits 24 Conclusion References 3 BASEBAND SIGNALS AND QUALITY OF SERVICE 31 Baseband signals 32 Performance objectives 33 Availability objectives 34 Delay 35 Conclusion References 4 DIGITAL COMMUNICATIONS TECHNIQUES 41 Baseband formatting 42 Digital modulation 43 Channel coding 44 Channel coding and the power-bandwidth trade-off 45 Coded modulation 46 End-to-end error control 47 Digital video broadcasting via satellite (DVB-S) 48 Second generation DVB-S 49 Conclusion References 5 UPLINK, DOWNLINK AND OVERALL LINK PERFORMANCE INTERSATELLITE LINKS 51 Configuration of a link 52 Antenna parameters 53 Radiated power 54 Received signal power 55 Noise power spectral density at the receiver input 56 Individual link performance 57 Influence of the atmosphere 58 Mitigation of atmospheric impairments 59 Overall link performance with transparent satellite 510 Overall link performance with regenerative satellite 511 Link performance with multibeam antenna coverage vs moonbeam coverage 512 Intersatellite link performance References 6 MULTIPLE ACCESS 61 Layered data transmission 62 Traffic parameters 63 Traffic routing 64 Access techniques 65 Frequency division multiple access (FDMA) 66 Time division multiple access (TDMA) 67 Code division multiple access (CDMA) 68 Fixed and on-demand assignment 69 Random access 610 Conclusion References 7 SATELLITE NETWORKS 71 Network reference models and protocols 72 Reference architecture for satellite networks 73 Basic characteristics of satellite networks 74 Satellite on-board connectivity 75 Connectivity through intersatellite links (ISL) 76 Satellite broadcast networks 77 Broadband satellite networks 78 Transmission control protocol 79 IPv6 over satellite networks 710 Conclusion References 8 EARTH STATIONS 81 Station organisation 82 Radio-frequency characteristics 83 The antenna subsystem 84 The radio-frequency subsystem 85 Communication subsystems 86 The network interface subsystem 87 Monitoring and control auxiliary equipment 88 Conclusion References 9 THE COMMUNICATION PAYLOAD 91 Mission and characteristics of the payload 92 Transparent repeater 93 Regenerative repeater 94 Multibeam antenna payload 95 Introduction to flexible payloads 96 Solid state equipment technology 97 Antenna coverage 98 Antenna characteristics 99 Conclusion References 10 THE PLATFORM 101 Subsystems 102 Attitude control 103 The propulsion subsystem 104 The electric power supply 105 Telemetry, tracking and command (TTC) and on-board data handling (OBDH) 106 Thermal control and structure 107 Developments and trends References 11 SATELLITE INSTALLATION AND LAUNCH VEHICLES 111 Installation in orbit 112 Launch vehicles References 12 THE SPACE ENVIRONMENT 121 Vacuum 122 The mechanical environment 123 Radiation 124 Flux of high energy particles 125 The environment during installation References 13 RELIABILITY OF SATELLITE COMMUNICATIONS SYSTEMS 131 Introduction of reliability 132 Satellite system availability 133 Subsystem reliability 134 Component reliability INDEX

322 citations


Patent
24 Jul 2014
TL;DR: In this paper, a multi-channel parallel scan data signal processor/digitizer processes the analog scan data signals along multiple cascaded multi-stage signal processing channels, to generate digital data signals corresponding to a laser scanned symbol, while a synchronized digital gain control module automatically processes the digital signals in response to start of scan (SOS) signals generated by a SOS detector.
Abstract: A laser scanning symbol reading system includes an analog scan data signal processor for producing digital data signals, wherein during each scanning cycle, a light collection and photo-detection module generates an analog scan data signal corresponding to a laser scanned symbol, a multi-channel parallel scan data signal processor/digitizer processes the analog scan data signal along multiple cascaded multi-stage signal processing channels, to generate digital data signals corresponding thereto, while a synchronized digital gain control module automatically processes the digital data signals in response to start of scan (SOS) signals generated by a SOS detector. Each signal processing channel supports different stages of amplification and filtering using a different set of band-pass filtering and gain parameters in each channel, to produce multiple digital first derivative data signals, and/or multiple digital scan data intensity data signals, having different signal amplitudes and dynamic range characteristics for use in decode processing.

296 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed the use of carrierless amplitude phase (CAP) in a novel multiband approach (MultiCAP) that achieves record spectral efficiency, increases tolerance towards dispersion and bandwidth limitations, and reduces the complexity of the transceiver.
Abstract: Short range optical data links are experiencing bandwidth limitations making it very challenging to cope with the growing data transmission capacity demands. Parallel optics appears as a valid short-term solution. It is, however, not a viable solution in the long-term because of its complex optical packaging. Therefore, increasing effort is now put into the possibility of exploiting higher order modulation formats with increased spectral efficiency and reduced optical transceiver complexity. As these type of links are based on intensity modulation and direct detection, modulation formats relying on optical coherent detection can not be straight forwardly employed. As an alternative and more viable solution, this paper proposes the use of carrierless amplitude phase (CAP) in a novel multiband approach (MultiCAP) that achieves record spectral efficiency, increases tolerance towards dispersion and bandwidth limitations, and reduces the complexity of the transceiver. We report on numerical simulations and experimental demonstrations with capacity beyond 100 Gb/s transmission using a single externally modulated laser. In addition, an extensive comparison with conventional CAP is also provided. The reported experiment uses MultiCAP to achieve 102.4 Gb/s transmission, corresponding to a data payload of 95.2 Gb/s error free transmission by using a 7% forward error correction code. The signal is successfully recovered after 15 km of standard single mode fiber in a system limited by a 3 dB bandwidth of 14 GHz.

274 citations


Journal ArticleDOI
TL;DR: This article provides an overview of the RF-powered CRNs and discusses the challenges that arise for dynamic spectrum access in these networks, and focuses on the trade-off among spectrum sensing, data transmission, and RF energy harvesting.
Abstract: Spectrum efficiency and energy efficiency are two critical issues in designing wireless networks. Through dynamic spectrum access, cognitive radios can improve the spectrum efficiency and capacity of wireless networks. On the other hand radio frequency (RF) energy harvesting has emerged as a promising technique to supply energy to wireless networks and thereby increase their energy efficiency. Therefore, to achieve both spectrum and energy efficiencies, the secondary users in a cognitive radio network (CRN) can be equipped with the RF energy harvesting capability, and such a network can be referred to as an RF-powered cognitive radio network. In this article we provide an overview of the RF-powered CRNs and discuss the challenges that arise for dynamic spectrum access in these networks. Focusing on the trade-off among spectrum sensing, data transmission, and RF energy harvesting, we then discuss the dynamic channel selection problem in a multi-channel RF-powered CRN. In the RF-powered CRN a secondary user can adaptively select a channel to transmit data when the channel is not occupied by any primary user. Alternatively, the secondary user can harvest RF energy for data transmission if the channel is occupied. The optimal channel selection policy of the secondary user can be obtained by formulating a Markov decision process (MDP) problem. We present some numerical results obtained by solving this MDP problem.

208 citations


Journal ArticleDOI
TL;DR: In this article, analog-to-digital and digital-toanalog converters (ADCs and DACs), as well as digital signal processing (DSP) functions for optical coherent modems are examined.
Abstract: We examine analog-to-digital and digital-to-analog converters (ADCs and DACs), as well as digital signal processing (DSP) functions for optical coherent modems.

206 citations


Patent
10 Nov 2014
TL;DR: In this paper, the authors present systems and methods for improved data communication between communication terminals such as a base station and an unmanned aerial vehicle (UAV) for uplink and downlink data transmission.
Abstract: The present invention provides systems and methods for improved data communication between communication terminals such as a base station and an unmanned aerial vehicle. In some instances, the systems and methods described herein provide robust transmission uplink data such as control data and wideband transmission of downlink data such as image data or other sensor data, while avoiding interference between the uplink data transmission and the downlink transmission.

201 citations


Journal ArticleDOI
TL;DR: In this article, the authors demonstrate QKD with bidirectional 10 Gb/s classical data channels in a single fiber using dense wavelength division multiplexing and achieve secure key rates of 2.38 Mbps and fiber distances up to 70 km.
Abstract: We demonstrate quantum key distribution (QKD) with bidirectional 10 Gb/s classical data channels in a single fiber using dense wavelength division multiplexing. Record secure key rates of 2.38 Mbps and fiber distances up to 70 km are achieved. Data channels are simultaneously monitored for error-free operation. The robustness of QKD is further demonstrated with a secure key rate of 445 kbps over 25 km, obtained in the presence of data lasers launching conventional 0 dBm power. We discuss the fundamental limit for the QKD performance in the multiplexing environment.

185 citations


Patent
21 Apr 2014
TL;DR: In this paper, the authors proposed an automatic recovery of failed connection in case of relay station orientation change due to influence of various external factors (wind, vibration, different intensity of heating of the bracing mountings at different time of day and others) and can be used in backhaul systems of base station sites for mobile networks.
Abstract: The invention relates to millimeter-wave point-to-point communication systems. A system comprises two separated millimeter-wave transceivers which provide high throughput data transmission and reception in frequency duplex mode and use high gain antennas capable of electronic scanning in some continuous angle range provided by the control module that implement control algorithms for antenna radiation pattern. Also a method based on the exploitation of scanning antennas of initial beam directions fine adjustment and subsequent beam directions tracking and readjustment when needed is proposed. The proposed system and method provide automatic recovery of failed connection in case of relay station orientation change due to influence of various external factors (wind, vibration, different intensity of heating of the bracing mountings at different time of a day and others) and can be used in backhaul systems of base station sites for mobile networks.

179 citations


Patent
27 Jan 2014
TL;DR: In this article, a group-wise deinterleaving technique was proposed to ensure good communication quality when using an LDPC code to transmit data, which can be applied to data transmission or the like.
Abstract: This technology pertains to a data-processing device and a data processing method that make it possible to ensure good communication quality when using an LDPC code to transmit data. In group-wise interleaving, an LDPC code having a code length (N) of 16,200 bits and a code rate (r) of 10/15 or 12/15 is interleaved on a per-bit-group basis, each bit group being 360 bits long. In group-wise deinterleaving, the interleaved LDPC code is restored to the original ordering thereof. This technology can be applied, for example, to data transmission or the like using an LDPC code.

Journal ArticleDOI
TL;DR: The results show that the proposed protocols have better performance than the existing secure protocols for CWSNs, in terms of security overhead and energy consumption.
Abstract: Secure data transmission is a critical issue for wireless sensor networks (WSNs). Clustering is an effective and practical way to enhance the system performance of WSNs. In this paper, we study a secure data transmission for cluster-based WSNs (CWSNs), where the clusters are formed dynamically and periodically. We propose two secure and efficient data transmission (SET) protocols for CWSNs, called SET-IBS and SET-IBOOS, by using the identity-based digital signature (IBS) scheme and the identity-based online/offline digital signature (IBOOS) scheme, respectively. In SET-IBS, security relies on the hardness of the Diffie-Hellman problem in the pairing domain. SET-IBOOS further reduces the computational overhead for protocol security, which is crucial for WSNs, while its security relies on the hardness of the discrete logarithm problem. We show the feasibility of the SET-IBS and SET-IBOOS protocols with respect to the security requirements and security analysis against various attacks. The calculations and simulations are provided to illustrate the efficiency of the proposed protocols. The results show that the proposed protocols have better performance than the existing secure protocols for CWSNs, in terms of security overhead and energy consumption.

Journal ArticleDOI
TL;DR: A new max-ratio relay selection policy is proposed to optimize the secrecy transmission by considering all the possible source-to-relay and relay- to-destination links and selecting the relay having the link which maximizes the signal to eavesdropper channel gain ratio.
Abstract: This paper considers the security of transmission in buffer-aided decode-and-forward cooperative wireless networks. An eavesdropper which can intercept the data transmission from both the source and relay nodes is considered to threaten the security of transmission. Finite size data buffers are assumed to be available at every relay in order to avoid having to select concurrently the best source-to-relay and relay-to-destination links. A new max-ratio relay selection policy is proposed to optimize the secrecy transmission by considering all the possible source-to-relay and relay-to-destination links and selecting the relay having the link which maximizes the signal to eavesdropper channel gain ratio. Two cases are considered in terms of knowledge of the eavesdropper channel strengths: exact and average gains, respectively. Closed-form expressions for the secrecy outage probability for both cases are obtained, which are verified by simulations. The proposed max-ratio relay selection scheme is shown to outperform one based on a max-min-ratio relay scheme.

Journal ArticleDOI
TL;DR: 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.
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 QoS (Quality of Service) 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 PSNR (Peak Signal-to-Noise Ratio), goodput, and inter-packet delay.

Journal ArticleDOI
TL;DR: This approach leads to considerable savings in node energy consumption, due to a significant reduction of the transmission ranges of the SN and RN nodes and the use of a one-hop transmission to communicate the data from the RNs to the UAV.
Abstract: The wireless sensor network (WSN) technology have been evolving very quickly in recent years. Sensors are constantly increasing in sensing, processing, storage, and communication capabilities. In many WSNs that are used in environmental, commercial and military applications, the sensors are lined linearly due to the linear nature of the structure or area that is being monitored making a special class of these networks; We defined these in a previous paper as Linear Sensor Networks (LSNs), and provided a classification of the different types of LSNs. A pure multihop approach to route the data all the way along the linear network (e.g. oil, gas and water pipeline monitoring, border monitoring, road-side monitoring, etc.), which can extend for hundreds or even thousands of kilometers can be very costly from an energy dissipation point of view. In order to significantly reduce the energy consumption used in data transmission and extend the network lifetime, we present a framework for monitoring linear infrastructures using LSNs where data collection and transmission is done using Unmanned Aerial Vehicles (UAVs). The system defines four types of nodes, which include: sensor nodes (SNs), relay nodes (RNs), UAVs, and sinks. The SNs use a classic WSN multihop routing approach to transmit their data to the nearest RN, which acts as a cluster head for its surrounding SNs. Then, a UAV moves back and forth along the linear network and transport the data that is collected by the RNs to the sinks located at both ends of the LSN. We name this network architecture a UAV-based LSNs (ULSNs). This approach leads to considerable savings in node energy consumption, due to a significant reduction of the transmission ranges of the SN and RN nodes and the use of a one-hop transmission to communicate the data from the RNs to the UAV. Furthermore, the strategy provides for reduced interference between the RNs that can be caused by hidden terminal and collision problems, that would be expected if a pure multihop approach is used at the RN level. In addition, three different UAV movement approaches are presented, simulated, and analyzed in order to measure system performance under various network conditions.

Journal ArticleDOI
TL;DR: In this paper, the authors developed a framework to characterize the system throughput as a function of arrival rate and per-device data rate for wireless systems in which randomly arriving devices attempt to transmit a fixed payload to a central receiver.
Abstract: For wireless systems in which randomly arriving devices attempt to transmit a fixed payload to a central receiver, we develop a framework to characterize the system throughput as a function of arrival rate and per-device data rate. The framework considers both coordinated transmission (where devices are scheduled) and uncoordinated transmission (where devices communicate on a random access channel and a provision is made for retransmissions). Our main contribution is a novel characterization of the optimal throughput for the case of uncoordinated transmission and a strategy for achieving this throughput that relies on overlapping transmissions and joint decoding. Simulations for a noise-limited cellular network show that the optimal strategy provides a factor of four improvement in throughput compared with slotted ALOHA. We apply our framework to evaluate more general system-level designs that account for overhead signaling. We demonstrate that, for small payload sizes relevant for machine-to-machine (M2M) communications (200 bits or less), a one-stage strategy, where identity and data are transmitted optimally over the random access channel, can support at least twice the number of devices compared with a conventional strategy, where identity is established over an initial random-access stage and data transmission is scheduled.

Patent
20 Aug 2014
TL;DR: In this paper, a method for transmitting data by using polar coding in a wireless access system, according to one embodiment of the present invention, may comprise the steps of deriving Bhattacharyya parameters according to data bits input for finding noise-free channels among equivalent channels, and allocating data payloads comprising data bits and cyclic redundancy check (CRC) bits to the found noise free channels.
Abstract: The present invention relates to data transmission/reception methods using a polar coding scheme, and devices for supporting same. The method for transmitting data by using polar coding in a wireless access system, according to one embodiment of the present invention, may comprise the steps of deriving Bhattacharyya parameters according to data bits input for finding noise-free channels among equivalent channels; allocating data payloads comprising data bits and cyclic redundancy check (CRC) bits to the found noise-free channels; inputting the data payloads into a polar encoder; and transmitting code bits output by the polar encoder, wherein the CRC bits may be allocated to better noise-free channels, among the noise-free channels indicated by the Bhattacharyya parameters, than the data bits.

Patent
17 Mar 2014
TL;DR: In this paper, a device for transmitting data between a vehicle and a data transmission device of a communications network, as part of a charging process of an electrical energy store of the vehicle, is disclosed.
Abstract: A device for transmitting data between a data transmission device of a vehicle and a data transmission device of a communications network, as part of a charging process of an electrical energy store of the vehicle, is disclosed. The vehicle data transmission device is based on a first communications protocol with a first signal level, while the communications network data transmission device is based on a second communications protocol with a second signal level. The device includes a signal-matching device having at least one first coupling transformer, which couples a data transmission device of a charging station to the data transmission devices of the vehicle and of the communications network via respective coils. The signal-matching device is configured to match the first signal level to the second signal level and vice versa.

Journal ArticleDOI
TL;DR: In this paper, the tradeoff among spectrum sensing, data transmission, and RF energy harvesting was discussed in a multi-channel RF-powered CRN, where the secondary user can adaptively select a channel to transmit data when the channel is not occupied by any primary user.
Abstract: Spectrum efficiency and energy efficiency are two critical issues in designing wireless networks. Through dynamic spectrum access, cognitive radios can improve the spectrum efficiency and capacity of wireless networks. On the other hand, radio frequency (RF) energy harvesting has emerged as a promising technique to supply energy to wireless networks and thereby increase their energy efficiency. Therefore, to achieve both spectrum and energy efficiencies, the secondary users in a cognitive radio network (CRN) can be equipped with the RF energy harvesting capability and such a network can be referred to as an RF-powered cognitive radio network. In this article, we provide an overview of the RF-powered CRNs and discuss the challenges that arise for dynamic spectrum access in these networks. Focusing on the tradeoff among spectrum sensing, data transmission, and RF energy harvesting, then we discuss the dynamic channel selection problem in a multi-channel RF-powered CRN. In the RF-powered CRN, a secondary user can adaptively select a channel to transmit data when the channel is not occupied by any primary user. Alternatively, the secondary user can harvest RF energy for data transmission if the channel is occupied. The optimal channel selection policy of the secondary user can be obtained by formulating a Markov decision process (MDP) problem. We present some numerical results obtained by solving this MDP problem.

Patent
05 Nov 2014
TL;DR: In this paper, a thin control channel structure is proposed to enable multiplexing of two or more data transmission formats, where a control channel can carry scheduling information, grants, etc., informing receiving devices of the puncturing that is occurring or will occur.
Abstract: Aspects of the disclosure provide for a thin control channel structure that can be utilized to enable multiplexing of two or more data transmission formats. For example, a thin control channel may carry information that enables ongoing transmissions utilizing a first, relatively long transmission time interval (TTI) to be punctured, and during the punctured portion of the long TTI, a transmission utilizing a second, relatively short TTI may be inserted. This puncturing is enabled by virtue of a thin channel structure wherein a control channel can carry scheduling information, grants, etc., informing receiving devices of the puncturing that is occurring or will occur. Furthermore, the thin control channel can be utilized to carry other control information, not being limited to puncturing information. Other aspects, embodiments, and features are also claimed and described.

Journal ArticleDOI
TL;DR: In this article, the main features of free-space optics (FSO) for terrestrial and inter-satellite communications are reviewed for 1 Gbps data transmission in both terrestrial and satellite communications.
Abstract: Complementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas.In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FSO

Journal ArticleDOI
TL;DR: In this paper, a joint brightness control and data transmission scheme was proposed to reduce the total power consumption while satisfying lighting and communication requirements in a visible light communication (VLC) system.
Abstract: This letter considers the efficient utilization of energy in a visible light communication (VLC) system. A joint brightness control and data transmission are presented to reduce the total power consumption while satisfying lighting and communication requirements. An optimization problem is formulated to determine the optimal parameters for the input waveform of light emitting diode (LED) lamps; this problem reduces the total energy consumption of the LED lamps while ensuring the desired brightness and communication link quality. The simulation results show that the proposed scheme increases the energy efficiency of the VLC system.

Proceedings ArticleDOI
20 Nov 2014
TL;DR: Ultra-broadband mm-wave wireless data transmission at 240 GHz carrier frequency is demonstrated successfully over a distance of 40m using a direct conversion MMIC-based RF front end.
Abstract: Ultra-broadband mm-wave wireless data transmission at 240 GHz carrier frequency is demonstrated successfully over a distance of 40m using a direct conversion MMIC-based RF front end. A new generation 64GS/s Fujitsu DAC evaluation board provides 64Gbit/s and 96Gbit/s data rates for QPSK and 8-PSK modulated baseband signals. The overall link performance is evaluated in terms of error vector magnitude (EVM) measurement. For the QPSK and 8-PSK data transmission EVM measurement shows values of 23.7% and 21.6%, respectively.

Journal ArticleDOI
TL;DR: Deterministic models that describe the energy consumption of Wi-Fi data transmission with traffic burstiness, network performance metrics like throughput and retransmission rate, and parameters of the power saving mechanisms in use are presented.
Abstract: Wireless data transmission consumes a significant part of the overall energy consumption of smartphones, due to the popularity of Internet applications. In this paper, we investigate the energy consumption characteristics of data transmission over Wi-Fi, focusing on the effect of Internet flow characteristics and network environment. We present deterministic models that describe the energy consumption of Wi-Fi data transmission with traffic burstiness, network performance metrics like throughput and retransmission rate, and parameters of the power saving mechanisms in use. Our models are practical because their inputs are easily available on mobile platforms without modifying low-level software or hardware components. We demonstrate the practice of model-based energy profiling on Maemo, Symbian, and Android phones, and evaluate the accuracy with physical power measurement of applications including file transfer, web browsing, video streaming, and instant messaging. Our experimental results show that our models are of adequate accuracy for energy profiling and are easy to apply.

Patent
01 Oct 2014
TL;DR: In this paper, the authors proposed a data transmission method and device that mainly comprises the steps of receiving transmission path switching messages of downlink data sent by source base stations for terminals, confirming number information of the data which are sent to the source BSs and do not yet receive uplink confirmation messages returned by the terminals and performing triggering to pause downlink sending, wherein the difference between the DL sending time corresponding to confirmed number information and the DL receiving time meets a set time interval.
Abstract: The invention discloses a data transmission method and device. The data transmission method mainly comprises the steps of receiving transmission path switching messages of downlink data sent by source base stations for terminals, confirming number information of the downlink data which are sent to the source base stations and do not yet receive uplink confirmation messages returned by the terminals and performing triggering to pause downlink data sending, wherein the difference between the downlink data sending time corresponding to confirmed number information and the time for receiving the transmission path switching messages meets a set time interval; triggering a starting function to send downlink data to target base stations of the terminals when uplink confirmation messages of the downlink data corresponding to confirmed number information are received. The problem that the downlink data sent to the target base stations by a network side are out of order due to time delay is effectively avoided, the problem that the downlink data received by the terminals and sent by the target base stations are out of order is effectively avoided, the problem of downlink data retransmission caused by the out-of-order situation is further avoided, and the network data transmission efficiency is improved.

Patent
Ivan Poupyrev1
14 Oct 2014
TL;DR: In this article, a radar system can both transmit data and sense gestures, thereby performing with a single system, control of many devices and data transmission with those devices, and also allowing high-bandwidth data transmission between devices.
Abstract: This document describes techniques and devices for radar-based gesture sensing and data transmission. The techniques enable, through a radar system, seamless and intuitive control of, and data transmission between, computing devices. This radar system can both transmit data and sense gestures, thereby performing with a single system, control of many devices and data transmission with those devices. Not only can this provide control of many devices, from refrigerators to laptops, this radar system also allows high-bandwidth data transmission between devices.

Journal ArticleDOI
TL;DR: A novel technological approach to space division multiplexing (SDM) based on the use of multiple individual fibers embedded in a common polymer coating material is presented, which is referred to as Multi- Element Fiber (MEF).
Abstract: A novel technological approach to space division multiplexing (SDM) based on the use of multiple individual fibers embedded in a common polymer coating material is presented, which is referred to as Multi-Element Fiber (MEF). The approach ensures ultralow crosstalk between spatial channels and allows for cost-effective ways of realizing multi-spatial channel amplification and signal multiplexing/demultiplexing. Both the fabrication and characterization of a passive 3-element MEF for data transmission, and an active 5-element erbium/ytterbium doped MEF for cladding-pumped optical amplification that uses one of the elements as an integrated pump delivery fiber is reported. Finally, both components were combined to emulate an optical fiber network comprising SDM transmission lines and amplifiers, and illustrate the compatibility of the approach with existing installed single-mode WDM fiber systems.

Patent
XinYu Hou1, Sheng Chang1, Rongyu Yang1, Guang Lu1
30 Sep 2014
TL;DR: In this article, a data transmission method, device and system to improve reliability of a data link is proposed, where the erroneous data is discarded and a data retransmission request is sent to the sender side to ensure correctness of received data and improve reliability.
Abstract: A data transmission method, device and system to improve reliability of a data link. When the sender side detects erroneous data, the erroneous data is discarded and a data retransmission request is sent to the sender side to ensure correctness of received data and improve reliability of the data link; and, when the sender side detects the erroneous data and a bit error rate is greater than a preset bit error rate threshold, the data link gets into auto recovery, and data transmission is resumed after the recovery succeeds, thereby avoiding an excessively high bit error rate, preventing an excessively high probability of omitted checks (the higher the bit error rate is, the higher probability of omitted checks is), and further improving reliability of the data link.

Journal ArticleDOI
TL;DR: It is shown that DRX reduces the end-to-end delay while FDRX has lower collision rate compared with DRX, and the tradeoffs regarding these approaches are outlined and draw future research directions for robust communication protocols for smart-grid monitoring applications.
Abstract: Monitoring smart-grid assets in a timely manner is highly desired for emerging smart-grid applications such as transformer monitoring, capacitor bank control, plug-in hybrid-electric-vehicle load management, and power quality assessment. Wireless sensor and actor networks (WSANs) are anticipated to be widely utilized in a wide range of smart-grid applications due to their numerous advantages along with their successful adoption in various critical areas including military and health. For resource-constrained WSANs, transmitting delay-critical data from smart-grid assets calls for data prioritization and delay responsiveness. In this paper, we introduce two medium-access approaches, namely, delay-responsive cross-layer (DRX) data transmission and fair and delay-aware cross-layer (FDRX) data transmission, which aim to address the delay and service requirements of smart grids. DRX is based on delay-estimation and data-prioritization steps that are performed by the application layer, in addition to the MAC layer parameters responding to the delay requirements of the smart-grid application and the network condition. On the other hand, FDRX incorporates fairness into DRX by preventing a few nodes from dominating the communication channel. We provide a comprehensive performance evaluation of those approaches. We show that DRX reduces the end-to-end delay while FDRX has lower collision rate compared with DRX. We outline the tradeoffs regarding these approaches and draw future research directions for robust communication protocols for smart-grid monitoring applications.

Journal ArticleDOI
TL;DR: It is shown that, for a large range of performance metrics, the data transmission efficiency of the ARQ schemes is determined by a set of parameters which are scheme-dependent and not metric-dependent.
Abstract: This paper investigates the performance of multiple-input-multiple-output (MIMO) systems in the presence of automatic repeat request (ARQ) feedback. We show that, for a large range of performance metrics, the data transmission efficiency of the ARQ schemes is determined by a set of parameters which are scheme-dependent and not metric-dependent. Then, the results are used to study different aspects of MIMO-ARQ such as the effect of nonlinear power amplifiers, large-scale MIMO-ARQ, adaptive power allocation and different data communication models. The results, which are valid for various forward and feedback channel models, show the efficiency of the MIMO-ARQ techniques in different conditions.