Optimization of wireless body area network performance with simplified electromagnetic model of the body

2020

Sensors

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In the paper, we present a novel approach to the optimum design of wearable antenna arrays intended for off-body links of wireless body area networks. Specifically, we investigate a four-element array that has a switchable radiation pattern able to direct its higher gain towards a signal source and a lower gain towards an interference. The aim is to increase the signal to interference ratio. We apply a genetic algorithm to optimize both the spatial placement and the feed phasing of the elementary on-body antennas. We propose a simplified, computationally efficient model for the simulation of the array radiation pattern. The model is based on full-wave simulations obtained with a simplified cylindrical model of the human body. We also propose, implement, and evaluate four objective functions based on signal to interference ratio, i.e., min-max, nadir point distance maximization, utopia point distance minimization, and full Pareto-like. Our optimized design obtained with this approach exhibits a significant performance improvement in comparison to the initial heuristic design.

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Section: Direct Problem Formulationsupporting

confidence: 72%

Optimal Design of Switchable Wearable Antenna Array for Wireless Sensor Networks

2020

Sensors

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“…The results presented and discussed in this section were obtained for a three-antenna system as described in Reference [ 20 ]. To make the results of our investigation more general, a very simple antenna was modeled in this study with the radiation pattern independent of rotation around the z -axis.…”

Section: Simulation and Optimization Resultsmentioning

confidence: 99%

“…Due to the influence of the human body on the wearable antenna radiation pattern for a wide range of radiation angles, the antenna gain can be very low. Depending on the position of the antenna on the human body, the antenna gain can be lower than −10 dBi for a sector wider than 100° in the horizontal plane [ 20 ]. When the propagation path between the human body and the remote receiver falls into the low gain zone of the antenna radiation pattern, the power of the received signal can drop below the receiver’s sensitivity.…”

Section: Wireless Body Area Sensor Networkmentioning

confidence: 99%

“…This two-antenna switched-pattern approach presented also in [ 20 ], can give a better system performance than a two antenna array operating with a single transceiver, a power splitter, and two waveguides. The wearable two-antenna array would suffer from a radiation pattern with deep interference minima which could cause a signal drop, particularly in outdoor environments [ 21 ].…”

Section: Wireless Body Area Sensor Networkmentioning

confidence: 99%

“…The time-diversity in off-body transmission from the two antennas located on the opposite sides of a body reduces the minima in the resultant horizontal pattern gain. Our solution can improve the link reliability in outdoor systems, depending on the particular position of the antennas with respect to the body [ 20 ]. To obtain a stable and reliable off-body link irrespective of the free movement of the user, the wearable antennas should have a quasi-omnidirectional pattern.…”

Section: Wireless Body Area Sensor Networkmentioning

confidence: 99%

See 2 more Smart Citations

Multi-Objective Optimization of a Wireless Body Area Network for Varying Body Positions

2018

Sensors

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The purpose of this research was to improve the performance of a wireless body area sensor network, operating on a person in the seated and standing positions. Optimization-focused on both the on-body transmission channel and off-body link performance. The system consists of three nodes. One node (on the user’s head) is fixed, while the positions of the other two (one on the user’s trunk and the other on one leg) with respect to the body (local coordinates) are design variables. The objective function used in the design process is characterized by two components: the first controls the wireless channel for on-body data transmission between the three sensor nodes, while the second controls the off-body transmission between the nodes and a remote transceiver. The optimal design procedure exploits a low-cost Estra, which is an evolutionary strategy optimization algorithm linked with Remcom XFdtd, a full-wave Finite-Difference Time-Domain (FDTD) electromagnetic field analysis package. The Pareto-like approach applied in this study searches for a non-dominated solution that gives the best compromise between on-body and off-body performance.

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Human Body Modelling for Wireless Body Area Network Optimization

2020 14th European Conference on Antennas and Propagation (EuCAP)

2020