Outage Probability Performance in Mobile Indoor Optical Wireless Communication Environment

3pagesInternational audienceIn this paper, we study an Optical Wireless Communication system for indoor healthcare monitoring application, taking into account the impact of indoor environment. We consider a diffuse link between an emitter placed on a mobile monitored patient and a base station located on the ceiling considering a one-bounce model. Thanks to Ray Propagation Simulator (RaPSor) developed at the Xlim-SIC laboratory, wall, floor and ceiling reflections are taken into account so that the system is more accurately designed, even for low data rates. This is of main concern for healthcare application because it is important to evaluate the required emitter power, related to the power autonomy of monitoring system

Utilisation de la technologie optique sans fils pour la transmission de données médicales en milieu confiné et sous contraintes de mobilité

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Wireless Optical technology based Body Area Network for health monitoring application

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Optical Wireless Links as an Alternative to Radio-Frequency for Medical Body Area Networks

International audienceIt is now established that optical wireless communications (OWC) technology is a promising alternative or a complement to radio-frequencies for indoor transmissions. Considering that using OWC permits the reduction of electromagnetic pollution in human environment, this technology can be also a good candidate for wireless body area networks (WBANs) in particular for medical applications such as health monitoring. In this paper, we investigate the use of on-body OWC for mobile medical WBAN. Based on transmission scheme exploiting diffuse optical reflections over the patient environment, we investigate a star BAN topology using spreading codes for multiple access. We have developed a theoretical analysis to determine the performance of such network considering that the patient is moving in the room. The achievable quality of service for a typical health monitoring application is reported and discussed regarding the performance required by medical applications

OCDMA Code Design for BER and Data Rate Differentiation in Beat Noise Corrupted Systems

International audienceUsing incoherent Optical Code Division Multiple Access (OCDMA) technique has recently attracted much interest since it appears to be not only a simple solution to provide user differentiation but also to perform service differentiation. The main limitation usually taken into account in the theoretical performance evaluation is Multiple Access Interference (MAI) linked to the fact that code sequences are unipolar and thus not strictly orthogonal. However, due to MAI and to the fact that the nature of the optical regime is not perfectly incoherent, beat noise constitutes another important limitation. We focus in this paper on multi-weight two dimensional (2-D) code sequences, which permits providing different BER services. We propose a theoretical statistical model to characterize MAI and beat noise impact. Thanks to this model, a theoretical error probability expression is established, taking into account both MAI and beat noise contribution in multimedia OCDMA systems. The design of multimedia codes satisfying targeted BERs can thus be done considering both limitations. The results permit highlighting the importance of beat noise consideration in the design process and the constraints imposed on optical source requirements

Performance evaluation of Wireless Optical Communication for mobile BAN scenario with blocking effects

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Optical Wireless Body Area Networks for Healthcare Applications

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Multiple Access Interference Impact on Outage Probability of Wireless Optical CDMA Systems

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Beat Noise Compensation in OCDMA Systems using soft decoding based FEC

International audienceIn this paper we study Forward Error Correction (FEC) under beat noise assumption in the context of incoherent Optical Code Division Multiple Access (OCDMA) systems. Due to the use of unipolar codes, Multiple Access Interference (MAI) amount and thus beatings between different user contributions known as beat noise, constitute important limitations in particular for high data rates. In order to compensate for these two major limitations, we propose a solution using FEC based on a soft decoding algorithm. For this purpose, we analyze the OCDMA received signal distribution and establish a new model, based on a mixture of chi-square distributions, valuable for any OCDMA code parameters and any source coherence time values. From this model, we establish the error probability analytical expression under beat noise assumption and determine the reliability parameters required for the FEC soft decoder initialization. To illustrate the performance, we use Low Density Parity Check (LDPC) codes and show that the LDPC adapted decoder is highly efficient in reducing beat noise and MAI for incoherent OCDMA systems, even when beat noise has a severe impact. In addition, we point out that this solution permits increasing data rates or number of active users