Theoretical and Experimental Approach for the Design of an Optical Wireless Physical Activity Monitoring System

Bas, Clément Le; Sahuguède, Stéphanie; Julien-Vergonjanne, Anne

doi:10.1007/s10776-017-0337-4

Cited by 10 publications

(5 citation statements)

References 19 publications

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“…As an example, for both channel models corresponding to young and elderly persons, Figure 15 shows the evolution of P tmin as a function of bandwidth B until 10 MHz for a given γ 0 of 15.6 dB and two targets P out values of 10 −1 and 10 −2 . Actually, it has been verified that a packet failure of 10% is a maximum tolerable value [47]. The value 0 = 15.6 dB for the most basic OWC modulation, i.e., on-off keying, corresponds to a bit error rate of 10 −9 , which is a classical metric for medical WBSN [10].…”

Section: Performance Of Wbsn Related To Power and Bandwidthmentioning

confidence: 99%

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Channel Modeling of an Optical Wireless Body Sensor Network for Walk Monitoring of Elderly

Kaba

Sahuguède

Julien-Vergonjanne

2021

Sensors

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The growing aging of the world population is leading to an aggravation of diseases, which affect the autonomy of the elderly. Wireless body sensor networks (WBSN) are part of the solutions studied for several years to monitor and prevent loss of autonomy. The use of optical wireless communications (OWC) is seen as an alternative to radio frequencies, relevant when electromagnetic interference and data security considerations are important. One of the main challenges in this context is optical channel modeling for efficiently designing high-reliability systems. We propose here a suitable optical WBSN channel model for tracking the elderly during a walk. We discuss the specificities related to the model of the body, to movements, and to the walking speed by comparing elderly and young models, taking into account the walk temporal evolution using the sliding windowing technique. We point out that, when considering a young body model, performance is either overestimated or underestimated, depending on which windowing parameter is fixed. It is, therefore, important to consider the body model of the elderly in the design of the system. To illustrate this result, we then evaluate the minimal power according to the maximal bandwidth for a given quality of service.

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Section: Performance Of Wbsn Related To Power and Bandwidthmentioning

confidence: 99%

“…As an example, for both channel models corresponding to young and elderly persons, Figure 15 shows the evolution of

as a function of bandwidth

until

for a given

of 15.6 dB and two targets

values of

and

. Actually, it has been verified that a packet failure of 10% is a maximum tolerable value [ 47 ].…”

Section: Performance Evaluationmentioning

confidence: 99%

Channel Modeling of an Optical Wireless Body Sensor Network for Walk Monitoring of Elderly

Kaba

Sahuguède

Julien-Vergonjanne

2021

Sensors

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“…Additionally, the effect of

was considered, as the IR reflectivity is generally higher than that of VLC [ 36 ]. Table 6 summarizes the effect of each of these quantities on the UL

uniformities in terms of

obtained for a typical hospital room size of 6.6 × 6.6 × 3 m

, as presented in [ 27 ]. It can be observed that

is similar to the corresponding

values for

and

(see Table 5 ), whereas the deviations are further reduced when the reflectivity is increased.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, the authors in [ 26 ] characterized the intra-OBAN channels by considering the effects of mobility and shadowing that occurred as a result of body parts and realistic body movements. In another study [ 27 ], the authors have reported the effects of several parameters, e.g., source directivity, transmitted optical power, position of on-body sensors, and the number of PDs that were installed on the ceiling. However, in all of these OBAN related studies, mainly the UL connection has been investigated and the impacts of fixed transmitter and receiver locations on the DL and UL communication, respectively, have been ignored.…”

Section: Related Workmentioning

confidence: 99%

A Heuristic Approach for Optical Transceiver Placement to Optimize SNR and Illuminance Uniformities of an Optical Body Area Network

Masroor

Jeoti

Drieberg

et al. 2021

Sensors

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The bi-directional information transfer in optical body area networks (OBANs) is crucial at all the three tiers of communication, i.e., intra-, inter-, and beyond-BAN communication, which correspond to tier-I, tier-II, and tier-III, respectively. However, the provision of uninterrupted uplink (UL) and downlink (DL) connections at tier II (inter-BAN) are extremely critical, since these links serve as a bridge between tier-I (intra-BAN) and tier-III (beyond-BAN) communication. Any negligence at this level could be life-threatening; therefore, enabling quality-of-service (QoS) remains a fundamental design issue at tier-II. Consequently, to provide QoS, a key parameter is to ensure link reliability and communication quality by maintaining a nearly uniform signal-to-noise ratio (SNR) within the coverage area. Several studies have reported the effects of transceiver related parameters on OBAN link performance, nevertheless the implications of changing transmitter locations on the SNR uniformity and communication quality have not been addressed. In this work, we undertake a DL scenario and analyze how the placement of light-emitting diode (LED) lamps can improve the SNR uniformity, regardless of the receiver position. Subsequently, we show that using the principle of reciprocity (POR) and with transmitter-receiver positions switched, the analysis is also applicable to UL, provided that the optical channel remains linear. Moreover, we propose a generalized optimal placement scheme along with a heuristic design formula to achieve uniform SNR and illuminance for DL using a fixed number of transmitters and compare it with an existing technique. The study reveals that the proposed placement technique reduces the fluctuations in SNR by 54% and improves the illuminance uniformity up to 102% as compared to the traditional approach. Finally, we show that, for very low luminous intensity, the SNR values remain sufficient to maintain a minimum bit error rate (BER) of 10−9 with on-off keying non-return-to-zero (OOK-NRZ) modulation format.

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“…We have also designed portable OWC devices to carry out experimental test-beds for low data rates infrared uplinks exploiting indoor diffuse reflections [12].…”

Section: Introductionmentioning

confidence: 99%

Infrared and visible links for medical body sensor networks

Lebas

Sahuguède

Julien-Vergonjanne

et al. 2018

2018 Global LIFI Congress (GLC)

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Abstract-Our previous studies focused on channel simulation and performance evaluation of optical wireless links for medical body sensor networks. This allowed us to increase our expertise in this field and to propose here a full optical wireless bidirectional system named as LiFi communication system for medical monitoring applications. The full duplex bidirectional communication is based on an infrared uplink and visible downlink. The studied scenario considers a patient wearing both an infrared transmitter connected to a medical sensor and a visible light receiver. The infrared receivers and visible light emitters are included in light fixtures at the ceiling. The study relies on channel modelling considering patient body features, locations and movements. Using ray-tracing technique associated to MonteCarlo method, we determine the overall performance in terms of outage probability. We apply our methodology considering various medical sensors and show that it is possible to satisfy the overall quality of service in terms of bit error rate and data rate.

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Theoretical and Experimental Approach for the Design of an Optical Wireless Physical Activity Monitoring System

Cited by 10 publications

References 19 publications

Channel Modeling of an Optical Wireless Body Sensor Network for Walk Monitoring of Elderly

Channel Modeling of an Optical Wireless Body Sensor Network for Walk Monitoring of Elderly

A Heuristic Approach for Optical Transceiver Placement to Optimize SNR and Illuminance Uniformities of an Optical Body Area Network

Infrared and visible links for medical body sensor networks

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