Recent developments in indoor optical wireless systems

Green, Roger J.; Joshi, Harita; Higgins, Matthew D.; Leeson, Mark S.

doi:10.1049/iet-com:20060475

Cited by 78 publications

(43 citation statements)

References 39 publications

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“…Each of the three constructing elements in a T feedback network can be in any form of the combinations of resistive, capacitive, or inductive elements to create any complex impedance to fit the frequency and transimpedance requirements of any particular application. Since this design can be an ideal front-end amplification solution to be applied to any charge/current detecting device, it can be introduced to other areas of applications, such as nuclear magnetic resonance (NMR) spectroscopy 26 or other spectroscopy systems, microscopy systems, 27 optical communication systems, 28 or charge-coupled devices (CCDs).…”

Section: Discussionmentioning

confidence: 99%

A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network

Lin

Green

O’Connor

2012

Review of Scientific Instruments

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A novel single-transistor transimpedance preamplifier has been introduced for improving performance in Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry. A low noise junction field-effect transistor (JFET), BF862, is used as the main amplification stage of this transimpedance preamplifier, and a T-shaped feedback network is introduced as both the feedback and the gate biasing solutions. The T feedback network has been studied using an operational amplifier (Op Amp), AD8099. Such a feedback system allows ∼100-fold less feedback resistance at a given transimpedance, hence preserving bandwidth, which is beneficial to applications demanding high gain. The single-transistor preamplifier yields a tested transimpedance of ∼10 4 (80 dB ) in the frequency range between 1 kHz and 1 MHz (mass-to-charge ratio, m/z, of around 180-180k for a 12-T FT-ICR system), with a low power consumption of ∼6 mW, which implies that this preamplifier is well suited to a 12-T FT-ICR mass spectrometer. In trading noise performance for higher transimpedance, an alternative preamplifier design, an AD8099 preamplifier with the T feedback network, has also been studied with a capability of ∼10 6 (120 dB ) transimpedance in the same frequency range. The resistive components in the T feedback network reported here can be replaced by complex impedances, which allows adaptation of this feedback system to other frequency, transimpedance, and noise characteristics for applications not only in other mass spectrometers, such as Orbitrap, time-of-flight (TOF), and ion trap systems, but also in other charge/current detecting systems such as spectroscopy systems, microscopy systems, optical communication systems, or charge-coupled devices (CCDs).

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Section: Discussionmentioning

confidence: 99%

A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network

Lin

Green

O’Connor

2012

Review of Scientific Instruments

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“…The concept of VLC systems revolves around 2 the use of light emitting diodes (LEDs) for both lighting and communications. The main drives for this new technology include the recent development of solid state lighting, longer lifetime of high brightness LEDs compared to other artificial light sources such as florescent and incandescent light bulbs, high data rate, low power consumption and green communications [1]- [5].…”

Section: Introductionmentioning

confidence: 99%

Uplink design in VLC systems with IR sources and beam steering

2017

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The need for high-speed local area networks to meet the recent developments in multimedia and video transmission applications has recently focused interest on visible light communication (VLC) systems. Although VLC systems provide lighting and communications simultaneously from light emitting diodes, LEDs, the uplink channel design in such a system is a challenging task. In this paper, we propose a solution in which the uplink challenge in indoor VLC is resolved by the use of an Infrared (IR) link. We introduce a novel fast adaptive beam steering IR system (FABS-IR) to improve the uplink performance at high data rates while providing security for applications. The goal of our proposed system is to enhance the received optical power signal, speed up the adaptation process and mitigate the channel delay spread when the system operates at a high transmission rate. The channel delay spread is minimised from 0.22 ns given by hybrid diffuse IR link to almost 0.07 ns. At 2.5 Gb/s, our results show that the imaging FABS-IR system accomplished about 11.7 dB signal to noise ratio (SNR) in the presence of multipath dispersion, receiver noise and transmitter mobility.Index Terms-uplink channel, beam steering IR, delay spread, SNR.

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“…Indoor optical wireless (OW) communication systems using an infrared (IR) carrier combine the high bandwidth availability of the optical domain with traits of mobility found in their radio frequency (RF) counterparts [1]. Coupling these features to form a high performance system requires the overcoming of the limitations imposed by the transmission channel, for which the characteristics are dependent upon the room size, stationary and moving objects, material properties of every surface the radiation is incident upon, and the number and type of illumination sources present [2].…”

Section: Introductionmentioning

confidence: 99%

Receiver alignment dependence of a GA controlled optical wireless transmitter

Higgins¹,

Green²,

Leeson³

2009

J. Opt. A: Pure Appl. Opt.

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Abstract. A genetic algorithm controlled multispot transmitter is demonstrated to be capable of optimising the received power distribution for single element receivers in fully diffuse mobile indoor optical wireless systems. By dynamically modifying the intensity of individual diffusion spots, the transmitter is capable of compensating for changes in receiver alignment, user movement and surface reflectivity characteristics, with negligible impact to bandwidth and RMS delay spread. The dynamic range, referenced against the peak received power, can be reduced by up to 27% when the room is empty, and up to 26% with user movement and variable receiver alignment. Furthermore, received power perturbation, induced by user movement, is reduced from 10% to 2.5%. This method shows potential for providing a highly adaptable solution of overcoming channel variability whilst also reducing receiver complexity.

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Recent developments in indoor optical wireless systems

Cited by 78 publications

References 39 publications

A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network

A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network

Uplink design in VLC systems with IR sources and beam steering

Receiver alignment dependence of a GA controlled optical wireless transmitter

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