High-speed Wireless Data Research Articles

Large-Signal Modulation Performance of Light-Emitting Diodes With Photonic Crystals for Visible Light Communication

Recently, GaN-based light-emitting diodes (LEDs) find their applications in, other than general lighting, visible light communication (VLC) for high-speed wireless data networks. The pursuit for more bandwidth from the LED can be realized by engineering the LED material structure and device design, or by modulation techniques. In this paper, we proposed GaN-based LEDs with the photonic crystal (PhC) structure for VLC applications. Contradictory to general thought that higher small frequency response translates to better large-signal performance, our results reveal that a PhC LED may not perform well at low data rate due to its relatively poorer signal-to-noise ratio (SNR). However, at higher data rates, the performance of PhC LEDs surpasses conventional LED structure. We showed data transmission capability of PhC LEDs with a bit rate up to 400 Mb/s using on–off keying modulation. To demonstrate the chip capability for large-signal transmission, without using preemphasis or postemphasis, VLC with 16-quadrature amplitude modulation orthogonal frequency-division multiplexing transmission capacity up to 2 Gbit/s is achieved with an error vector magnitude of 17.07%, SNR of 15.35 dB, and bit error rate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.3 \times {10}^{-3}$ </tex-math></inline-formula> . Our LEDs embedded with PhCs pass the forward error correction criterion. The results reveal the advantages of LEDs with PhC for achieving higher data rate transmission.

ICLE Comments in Opposition to Petition to Deny T-Mobile-Sprint Merger

ICLE’s comments argue that the petitions to deny fail to provide any compelling reason to adopt a presumption against this merger. To the contrary, there are good reasons to think that this transaction will benefit consumers and the economy. As ICLE scholars discuss in these comments, increased concentration is not necessarily good or bad in itself — it depends on the circumstances. Increases in market concentration in the US mobile industry have historically been accompanied by dramatic increases in quality and reductions in price. And there are compelling reasons to believe that the merger of T-Mobile and Sprint will continue this trend. Indeed, the potential benefits of the deal — including wider access to, and more timely deployment of, high-speed wireless data at lower cost, as well as a host of other innovations—are considerable. In order to ensure that such consumer benefits can be realized, it is crucial that the proposed merger not be thwarted by regulators inappropriately focused on short-term, static effects.

Design of a system solution that modernizes legacy supervisory control and data acquisition systems as an early detection system

Background In industrial disasters, early detection of problems and crisis management are critical for saving the lives of people and reducing the impact of disasters. Purpose In this study, we design a special gateway system that bridges the gap between different communication protocols and enables legacy supervisory control and data acquisition systems to function early detection systems for potential industrial disasters. Methods The system uses a new queue mechanism to substantially improve the problem of data loss found in conventional supervisory control and data acquisition systems and utilizes identification (ID) prioritization to enable early detection of problems. The proposed system is implemented and tested on a Linux-based, 3G-capable Modbus gateway system. Modbus is used as the communication protocol and 3G technology is utilized to provide high-speed wireless data transfer components. The Modbus gateway device uses an ARM-based EP9302 processor and has digital input/output, relay outputs, and RS485 outputs. Conclusion This study is significant as it is the first work to show the application of the priority query execution method for Modbus gateway devices.

Toward an Efficient C-RAN Optical Fronthaul for the Future Networks: A Tutorial on Technologies, Requirements, Challenges, and Solutions

The exponential traffic growth, demand for high speed wireless data communications, as well as incessant deployment of innovative wireless technologies, services, and applications, have put considerable pressure on the mobile network operators (MNOs). Consequently, cellular access network performance in terms of capacity, quality of service, and network coverage needs further considerations. In order to address the challenges, MNOs, as well as equipment vendors, have given significant attention to the small-cell schemes based on cloud radio access network (C-RAN). This is due to its beneficial features in terms of performance optimization, cost-effectiveness, easier infrastructure deployment, and network management. Nevertheless, the C-RAN architecture imposes stringent requirements on the fronthaul link for seamless connectivity. Digital radio over fiber-based common public radio interface (CPRI) is the fundamental means of distributing baseband samples in the C-RAN fronthaul. However, optical links which are based on CPRI have bandwidth and flexibility limitations. Therefore, these limitations might constrain or make them impractical for the next generation mobile systems which are envisaged not only to support carrier aggregation and multi-band but also envisioned to integrate technologies like millimeter-wave (mm-wave) and massive multiple-input multiple-output antennas into the base stations. In this paper, we present comprehensive tutorial on technologies, requirements, architectures, challenges, and proffer potential solutions on means of achieving an efficient C-RAN optical fronthaul for the next-generation network such as the fifth generation network and beyond. A number of viable fronthauling technologies such as mm-wave and wireless fidelity are considered and this paper mainly focuses on optical technologies such as optical fiber and free-space optical. We also present feasible means of reducing the system complexity, cost, bandwidth requirement, and latency in the fronthaul. Furthermore, means of achieving the goal of green communication networks through reduction in the power consumption by the system are considered.

65-nm CMOS 공정을 이용한 V-Band 차동 저잡음 증폭기 설계

In this paper, V-band differential low noise amplifier(LNA) using 65-nm CMOS process for high speed wireless data communication is presented. The LNA is composed of 3-stage common-source differential amplifiers with neutralization of feedback capacitances using MOS capacitors and impedance matching utilizing transformers. The fabricated LNA has a peak gain of 23 dB at 63 GHz and 3 dB bandwidth of 6 GHz. The chip area of LNA is 0.3 mm2 and the LNA consumes 32 mW DC power from 1.2 V supply voltage.

Analysis of Turbo Code Behavior with Extrinsic Information Transfer Charts in High-Speed Wireless Data Services

This paper examines turbo codes that are currently introduced in many international standards and implemented in numerous advanced communication systems, and evaluates the process of extrinsic information transfer (EXIT). The convergence properties of the iterative decoding process, associated with a given turbo-coding scheme, are estimated using the analysis technique based on so-called extrinsic information transfer (EXIT) charts. This approach provides a possibility to predict the bit-error rate (BER) of a turbo code system with only the extrinsic information transfer chart. It is shown that extrinsic information transfer charts are powerful tools to analyze and optimize the convergence behavior of iterative systems utilizing the turbo principle, i.e., systems exchanging and refining extrinsic information. The idea is to consider the associated soft-input soft-output (SISO) stages as information processors, which map input a priori log likelihood ratios (LLRs) onto output extrinsic LLRs, the information content being obviously assumed to increase from input to output, and introduce them to the design of turbo systems without the reliance on extensive simulation. Compared with the other methods for generating extrinsic information transfer functions, the suggested approach provides insight into the iterative behavior of linear turbo systems with substantial reduction in numerical complexity.

Room-Temperature Oscillation of Resonant Tunneling Diodes close to 2 THz and Their Functions for Various Applications

Compact and coherent source is a key component for various applications of the terahertz (THz) wave. We report on our recent results of THz oscillators using resonant tunneling diodes (RTDs). To achieve high-frequency oscillation, the electron delay time of RTD was reduced with a narrow quantum well and an optimized collector spacer thickness. Conduction loss at the air bridge connecting RTD and slot antenna, which works as a resonator and a radiator, was also reduced. By these structures, a fundamental oscillation up to 1.92 THz was obtained at room temperature. Theoretical calculation shows that an oscillation over 2 THz is further expected by improved structures of RTD and antenna. Using the offset slot antenna and two-element array configuration, high output power of 0.61 mW was obtained at 620 GHz. A direct intensity modulation of RTD oscillators up to 30 GHz, which is useful for high-speed wireless data transmission, was demonstrated. By the integration of a varactor diode, wide frequency sweep of 580–700 GHz in a single device and 580–900 GHz in a four-element array were also demonstrated. This result expands possible applications of RTD oscillators.

ENGLISH

2 ABSTRACT: Light Emitting Diodes are set to penetrate many areas of everyday life. An interesting property of these devices in addition to their lightening capabilities , is that they can also be utilised for data transmissions as well. LED's require low power for their operation and have very high switching speeds. This dual purpose application can reduce our dependency on the densely used means of communication the Radio frequency communication.. Visible light communication (VLC) technique using White Light Emitting Diode (LED ) is a promising technology for next generation communication for short range , high speed wireless data transmission. LEDs have a number of advantages, one of which is long life expectancy. LEDs' ability to transfer information signals over light makes it a very good communication medium. Now the light we use in our daily life is not only be used for providing light but also for communication. However, like many emerging technologies, VLC has many technical issues that need to be addressed. Using visible light for data transmission entails many advantages and eliminates most drawbacks of transmission via electromagnetic waves outside the visible spectrum .In this paper, inexpensive transmitter and receiver of (VLC) system is designed and implemented experimentally for transmitting data between two computers using Hyper Terminal software.

Optical Repeater Assisted Visible Light Device-to-Device Communications

Device-to-device (D2D) communication is considered a promising technique to provide wireless peer-to-peer communication services. Due to increasing demand on mobile services, available spectrum for radio frequency (RF) based communications becomes scarce. Recently, visible light communications (VLC) has evolved as a high speed wireless data transmission technology for indoor environments with abundant available bandwidth. In this paper, a novel VLC based D2D communication that provides wireless peer-to-peer communication is proposed. Potential low operating power devices for an efficient D2D communication over increasing distance of separation between devices is analyzed. Optical repeaters (OR) are also proposed to enhance the performance in an environment where direct D2D communications yield degraded performance. Simulation results show that VLC plays an important role in providing efficient D2D communication up to a distance of 1 m between devices. It is also found that the OR significantly improves the coverage distance up to 3.5 m. Keywords—Visible light communication, light emitting diode, device-to-device, optical repeater.

An Inductively Powered Wireless Solid-State Drive System With Merged Error Correction of High-Speed Wireless Data Links and NAND Flash Memories

A highly reliable wireless solid-state drive (SSD) system for future applications of large volume storage is presented. The wireless interface in the system consists of an inductively coupled power link with fast transmission power control and high-speed data links using transmission line couplers (TLCs). The wireless power link can deliver 1 W from the host to the SSD. The full duplex wireless data interface achieves raw data rate of 1.6 Gb/s. The reliability of the wireless interface is studied though simulation analysis and experiments. The error correction block for the NAND flash memory system can also correct errors in the wireless data links, allowing the requirements for the PHY layer to be relaxed. The error correction code is discussed, including optimization by analyzing the error bits on the wireless data links. The experimental results confirmed strong tolerance to the interference from the power link on the wireless data link, and the water proof property of both the data and power links.

Video Streaming Over WIMAX with Ant Colony Optimization for Health Applications

This paper presents a new proficiency WiMAX embodies the IEE 802.16 family of standards, providing wireless broadband access. With IEEE 802.16e, the mobility amendment and WiMAX guarantees to address the ever-increasing demand of mobile high-speed wireless data in fourth generation (4G) networks. In the existing work, video distribution has been considered as a basic technique that involves scheduling and content-aware video streaming since the video is transmitted as different frames there is a chance of getting either mismatched frames at the receiver or loss of frames owing to incorrect threading of the video frames. Due to these reasons, the expected throughput may not be obtained ,to improve the quality of service and to overcome this ailment, the proposed work establish the Ant colony optimization(ACO) prototype.ACO algorithm includes two mechanism: trail evaporation and deamon actions which acts effectively to trigger the accumulation of data being collected at the receiver end. This marches to provide desired QOS and throughput especially in the trait of medical application.

Design of Intelligent Vehicle Monitoring System Based on μC-OS

This paper establishes a set wireless intelligent vehicle monitoring system can be used in car based on S3C2440 and UC-OS, including hardware design, software design, system terminal high-speed wireless data transmission and monitoring platform. The experimental results show that the system have high detection sensitivity and high accuracy, and that can effectively prevent drunk driving and theft has very good practical value.

Application of OFDM Technology in 4G Mobile Network

OFDM (Orthogonal Frequency Division Multiplexing) is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier exists orthogonality and great use of spectrum resources. To a certain extent, the problem of shortage of spectrum resources will be eased in the future. OFDM has a good ability to resist inter symbol interference and fight against frequency selective fading, and be able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement and meet the need of the business in the wireless communication system. The paper introduces the basic principle of OFDM technology, describes the advantages of OFDM and the defects needed to be overcome. Moreover, we analyzes the characteristics of 4G technology and discusses the application of OFDM in 4G mobile network.

Energy Efficient Programmable MIMO Decoder Accelerator Chip in 65-nm CMOS

This paper presents an energy efficient programmable hardware accelerator that targets multiple-input-multiple-output (MIMO) decoding tasks of orthogonal frequency-division multiplexing (OFDM) systems. The work is motivated by the adoption of MIMO and OFDM by almost all existing and emerging high-speed wireless data communication systems. The accelerator was fabricated in 65-nm CMOS technology and occupies a core area of 2.48 mm 2 . It delivers full programmability across different wireless standards (i.e., WiFi, 3G-long term evolution, and WiMax) as well as different MIMO decoding algorithms (i.e., minimum mean square error, singular value decomposition, and maximum likelihood) with extreme energy efficiency. The energy efficiency of our MIMO accelerator chip was compared against dedicated application specific integrated circuits for 4 × 4 QR decomposition, 4 × 4 singular value decomposition, and 2 × 2 minimum mean square error decoding. Despite the programmable nature of our design, it delivered energy efficiencies that were 18% to 28% better than the dedicated solutions reported in the literature. This paper presents the VLSI implementation of the architecture discussed in [14]-[16]. It discusses the implementation decisions and tradeoffs used to ensure minimum overall energy consumption of the resulting accelerator chip without sacrificing programmability. Given its programmability and extreme energy efficiency, the accelerator is an ideal solution for today's smart phones that implement multiple MIMO-OFDM waveforms on the same platform.

SMS Remote Control System Based on GSM

In recent years, mobile communication technology develops at an alarming rate and the development of mobile communications technology enables high-speed wireless data applications become possible. SMS Remote Control System Based on GSM uses mobile phone as the tools for sending control commands, SMS group sending device as the tools to receive the control instruction, PC as the analytical tools for the control commands, and smart appliances as the final controlled objects. It is an ultra long-range wireless control system based on the global mobile communications network.

Voice Service Solutions in Evolved Packet System

EPS network is the future direction of mobile network, and voice service is still important in the EPS network. In the conventional 2G/3G mobile communication, voice service is provided by circuit switching in the CS domain. As the LTE core network provides the access to high-speed and lower latency wireless packet data on the air interface 3GPP retains the PS domain rather than the CS domain in designing the core network. And voice service which is included in the packet domain is available through VOIP. To ensure high-quality voice services, 3GPP proposes two solutions: CSFB and SRVCC. Each option has its own applied conditions, advantages and disadvantages. This article first introduces EPC network framework and the functions of its core functional entities. Then the network framework and voice processing of the two programs (CSFB and SRVCC) are compared. At last, a conclusion of advantages and disadvantages of the two programs is given, and it will lay the basis for different options.

A High-Speed Wireless Transmission Scheme for Wireless Sensor Network

Along with more extensive application of wireless sensor network (WSN) technology, real-time and a large amount of data transmission requires WSN system to achieve high-speed transmission. Therefore, a high-speed wireless data transmission scheme is an essential requirement in WSN environment. We propose a modified WiFi (Wireless Fidelity) protocol for wireless transmission and high speed serial peripheral interface, and design a single-node system to test the scheme. The experimental result shows that the average transmission rate of the system can reach 893.1kb/s, meet the demand for high-speed wireless transmission.

Compact LTCC-based Multilayer Ultrawideband(UWB) Bandpass Filter Composed of Broadside-Coupled E-shaped Electrodes

Ultra-wideband (UWB) wireless communication systems, utilizing a huge frequency range from 3.1 ㎓ to 10.6 ㎓, are one of the key technologies to meet tremendous demands for up-coming high-speed wireless data communications. The hardware of such systems requires to be made very compact and highly functional. In this paper, research history of our planar-type UWB band-pass filters composed of capacitively couped E-shaped electrodes is outlined first. After that, a super-compact multi-layered UWB bandpass filter is newly developed by using the E-shaped electrode architecture. The designed filter, with overall dimensions of 5.0 x 5.0 x 0.95 mm3, has a UWB passband from 3.3 ㎓ to 10.7 ㎓ in simulation (a fractional bandwidth of 106 %) and from 3.5 ㎓ to 10.7 ㎓ in experiment (a fractional bandwidth of 100%). In addition, the filter has attractive transmission zeros just below and above the passband, whose creation mechanism is studied theoretically. Also, useful design procedure is introduced for this filter.

Characterization of a Linearly Chirped FBG Under Local Temperature Variations for Spectral Shaping Applications

We develop and experimentally validate a method to characterize linearly chirped fiber Bragg gratings (CFBGs) under local temperature perturbations for tunable spectral shaping. The heat distribution along the FBG is modeled by a Gaussian-Lorentzian function. The phase and apodization profiles of the CFBG are characterized by measuring the complex reflection spectrum and subsequently using inverse scattering. Finally, coupled mode theory is used to predict the transmittivity of the CFBG under the local temperature perturbations. As an application, we use our model to spectrally shape the spectrum of a gain-switched laser (GSL) and generate ultra-short, optimally designed pulses for high speed wireless data distribution in indoor environments.

MIMO 채널에서 LLR 추정을 위한 저 계산량 알고리즘

차세대 무선통신에서는 다양한 서비스, 높은 신뢰도와 함께 빠른 전송속도를 요구한다. 이러한 요구를 만족시키기 위해서 MIMO 시스템과 LDPC 부호를 결합하는 방법에 대한 많은 연구가 이루어지고 있다. MIMO 시스템과 LDPC 부호의 결합시 LDPC 복호기에는 각 채널에서 수신되는 정보를 이용하여 연판정된 비트를 LDPC 복호기에 입력되어야 한다. 기존의 방식은 모든 수신된 신호를 이용하여 연판정된 비트를 분리하여 많은 계산량이 필요로 하는데, 본 논문에서는 후보 벡터를 이용하여 성능의 감소없이 연판정된 비트를 분리하여 최대 61%의 계산량을 감소하는 방식을 제시하였다. In recent years, the goal of providing high speed wireless data services has generated a great amount of interest among the research community. Several researchers have shown that the capacity of the system, in the presence of flat Rayleigh fading, improves significantly with the use of combined MIMO and LDPC. To feed the soft values to LDPC decoder, the soft values must be calculated from multiple transmitter and receiver antennas in Rayleigh fading channel. It requires high computational complexity to get the soft symbols by increasing number of transmitter and receiver antennas. Therefore, this thesis proposed on effective algorithm for calculation of soft values from multiple antennas based on LLR. As result, This thesis shows that maximum 61% of computational complexity is reduced with a little loss of performance.