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Kista, Sweden

Bit-Error-Ratio (BER) of intensity modulated optical orthogonal frequency division multiplexing (OFDM) system is analytically evaluated accounting for nonlinear digital baseband distortion in the transmitter and additive noise in the photo receiver. The nonlinear distortion that is caused by signal clipping and quantization is taken into consideration. The signal clipping helps to overcome the system performance limitation related to high peak-to-average power ratio (PAPR) of the OFDM signal and to minimize the value of optical power that is required for achieving specified BER. The signal quantization due to a limited bit resolution of the digital to analog converter (DAC) causes an optical power penalty in the case when the bit resolution is too low. By introducing an effective signal to noise ratio (SNR) the optimum signal clipping ratio, system BER and required optical power at the input to the receiver is evaluated for the OFDM system with multi-level quadrature amplitude modulation (QAM) applied to the optical signal subcarriers. Minimum required DAC bit resolution versus the size of QAM constellation is identified. It is demonstrated that the bit resolution of 7 and higher causes negligibly small optical power penalty at the system BER = 10-3 when 256-QAM and a constellation of lower size is applied. The performance of the optical OFDM system is compared to the performance of the multi-level amplitude-shift keying (M-ASK) system for the same number of information bits transmitted per signal sample. It is demonstrated that in the case of the matched receiver the M-ASK system outperforms OFDM and requires 3 - 3.5 dB less of optical power at BER = 10-3 when 1 - 4 data bits are transmitted per signal sample. © 2011 Optical Society of America.

After 40 years of research and development, today continuous glucose monitoring (CGM) is demonstrating the benefit it provides for millions with diabetes. To provide in vivo accuracy, new permselective membranes and mediated systems have been developed to prevent enzyme saturation and to minimize interference signals. Early in vivo implanted sensor research clearly showed that the foreign body response was a more difficult issue to overcome. Understanding the biological interface and circumventing the inflammatory response continue to drive development of a CGM sensor with accuracy and reliability performance suitable in a closed-loop artificial pancreas. Along with biocompatible polymer development, other complimentary algorithm and data analysis techniques have improved the performance of commercial systems significantly. For example, the mean average relative difference of Dexcom's CGM system improved from 26 to 14 % and its use-life was extended from 3 to 7 d. Significant gains in usability, including size, flexibility, insertion, calibration, and data interface, have been incorporated into new generations of commercial CGM systems. Besides Medtronic, Dexcom, and Abbott, other major players are also investing in CGM. Becton Dickinson is conducting clinical trials with an optical galactose glucose binding system. Development of fully implanted sensor systems fulfills the desire for a discreet, reliable CGM system. Research continues to find innovative ways to help make living with diabetes easier and more normal, and new segments are being pursued (intensive care unit, surgery, behavior modification) in which CGM is being utilized. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vanin E.,Acreo Ab
Optics Letters | Year: 2011

It is well known that deliberate signal clipping in an intensity-modulated (IM) laser transmitter helps to overcome the optical orthogonal frequency division multiplexing (OFDM) system performance limitation that is related to the signal high peak-to-average power ratio. The amplitude of a clipped OFDM signal has to be optimized in order to minimize the optical power that is required to achieve a specified system performance. However, the signal clipping introduces nonlinear distortion (so-called clipping noise) and leads to a system performance penalty. In this Letter, the performance of the IM optical OFDM system with digital baseband clipping distortion in the transmitter and clipping noise compensation by means of signal restoration in the digital signal processing unit of the system receiver is analytically evaluated. It is demonstrated that the system bit-error ratio can be reduced by more than an order of magnitude, from 10-3 to 3:5 × 10-5, by applying only the first iteration of the signal restoration algorithm proposed in this Letter. The results of the analytical analysis are verified with brute-force numerical simulations based on direct error counting. © 2011 Optical Society of America.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: COMPET-06-2014 | Award Amount: 1.13M | Year: 2015

C3PO: advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects represents a radical improvement in performance of existing ground to low earth orbit communication systems in terms of weight reduction, on-board power consumption, data rate and communication security & confidentiality. C3PO in figures: - Mass reduction by a factor 14 - On-board power consumption reduction by a factor 100 - Data rate increase by a factor 2 The projects objectives are to - Design a solution to improve actual downlink and uplink communication systems based on a non-space disruptive technology - Improve enabling Space Surveillance & Tracking technologies performances to meet the final system needs - Increase the Multiple Quantum Well Technology Readiness Level from 2 to 4 - Improve the overall perfromance of space communication systems - Identify the C3PO system market and Business Model - Increase the system safety (including regulation and governance issues) This is achieved through an operational analysis of the final system, the validation of major system parameters through 2 experiments, the consolidation of the system architecturen the elaboration of the associated development roadmap and the definition of the system Business Model. The Multiple Quantum Well retro-reflector technology, derived from non-space domain, is incorporated into the current state of the art as a high-rate lightweight communication device. Its development in the space sector has a disruptive impact on the satellites and satellite imagery markets, enabling new missions such as CubeSat earth observations. The proposed project serve the Unions Common Security & Defence Policy by increasing the satellite communications security. C3PO mobilises traditional space actors and non-space actors such as TEMATYS (SME) and ACREO (Research).

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: ICT-02-2014 | Award Amount: 8.22M | Year: 2014

Smart-MEMPHIS project addresses the increasing demand for low-cost, energy-efficient autonomous systems by focusing on the main challenge for all smart devices - self-powering. The project aims to design, manufacture and test a miniaturized autonomous energy supply based on harvesting vibrational energy with piezo-MEMS energy harvesters. The project will integrate several multi-functional technologies and nanomaterials; lead-zirconate-titanate materials in MEMS-based multi-axis energy harvester, an ultra-low-power ASIC to manage the variations of the frequency and harvested power, a miniaturized carbon-nano material based energy storing supercapacitor, all heterogeneously integrated with new innovative flat panel packaging technologies for cost effective 3D integration verified through manufacturability reviews. The performance of the system will be demonstrated in two demanding applications: leadless bio-compatible cardiac pacemaker and wireless sensor networks (WSN) for structure health monitoring (SHM). For the pacemaker, a smart energy autonomous system will accelerate the paradigm shift from costly, burdensome surgical treatments to cost-effective and patient-friendly minimally invasive operations enabled by leadless pacemakers capable of harvesting energy from the heart beats. The key challenges for the energy harvesting arise from the extremely stringent reliability requirements, the low vibrational energies and frequencies and the small size required for a device implanted inside a heart. With the 2nd demonstrator the consortium consisting of multi-functional value chain will show a wider applicability for the technologies complementing the medical application. A WSN with acoustic sensor nodes will be demonstrated in SHM applications. SHM enables real-time monitoring of complex structures e.g. survey and detection of micro-cracks for example in composite aircraft wings, bridges or rails, or detection of corrosion or leakage in pipes solving.

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