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As increased requirements for much high speed and capacity in wireless communications, frequency bands become higher, such as millimeter wave or terahertz wave. In these high frequency bands, beamforming is employed to gain stable connectivity. On-body body area network is one of fascinate application of these high capacity frequency bands. However, directions of on-body antennas largely varies and...
This paper investigates a transmission power control scheme based on the context-specific temporal correlation model in WBAN. Firstly construction of the context-specific temporal correlation model is presented. After that a channel estimation method using the last known channel gain and the constructed temporal correlation model is explained. The channel estimation is then used in our proposed transmission...
In wireless body area networks (WBANs) measurements, the performance of on-body channels has been affected by surrounding environment. When conducting WBAN measurement in full anechoic chamber, the on-body signal propagation might be influenced by wave absorbers especially the on-floor wave absorbers (as they are close to human body). In this paper, the simulation approach, based on the frequency-dependent...
Propagation channel of body area networks fluctuates by shadowing caused by human movement. However, to make dynamic BAN channel model for individual human motion by few parameters is not easy, so most of the channel modeling in BANs are performed with statistical treatment of human motions. In this paper, as an attempt to treat individual human motions in BAN channel modeling, a geometrical modeling...
For designing reliable wireless body area network (WBAN) systems, channel modeling plays an important role. Antenna de-embedding, in which the contribution of antennas is separately modeled from the channel, has been one of the biggest challenges in WBAN channel modeling. While the antenna de-embedding in mobile communication has been achieved by double-directional channel modeling, this approach...
Electromiogram (EMG) is an useful technique to measure activity of human muscle. However, it is not easy to deploy EMG sensors with portable sensor networks (e.g. body area network), as it requires exact positioning of probes and noise issue. The authors propose ultrasonic echo based human muscle activity monitoring to overcome these issues. In this paper, activity of muscle of upper arm is measured...
This paper deals with the two-dimensional scattering problem of electromagnetic wave from a lossy dielectric cylinder which its material is modeled by the multiple poles Debye model. This scattering problem is numerically treated using the two-dimensional finite-difference time-domain (2D-FDTD) method with pulse excitation source. The total field (including incident and scattered fields) from a circular...
To design sufficiently reliable wireless body area network (WBAN) system for future health-care, channel modeling plays an important role. Especially from the viewpoint of antenna optimization, the channel modeling approach should be able to de-embed the antenna contribution to the channel response. Two modeling approaches using spherical wave functions (SWFs) and orthogonal dipoles (ODs) have been...
This paper investigated the feasibility of using the radio signal strength of sensors placed around the human body in the human movement identification. This proposed method can identify the human movement in WBAN using only the radio signal strength, thus any additional tools are not necessary. OpenNICTA provides the BAN measurement channel in three kinds of human motions, which are running, walking...
For designing reliable and low-power wireless body area network (WBAN) systems, channel modeling plays an important role. However, coupling between antennas and a human body hinders from separately modeling their individual contributions. Therefore, this paper proposes an antenna de-embedding scheme that is based on the channel modeling by means of spherical wave functions (SWFs). A preliminary validation...
The pyramidal wave absorbers are widely used in anechoic chambers which frequently used for EMC or antenna measurements. It is important to know reflection characteristics of pyramidal absorbers to improve the performance of anechoic chambers. It is known that diffracted or scattered waves are excited when the pyramidal wave absorber is irradiated by a plane wave, thus to know the characteristics...
In this paper, we have fundamentally studied the estimation of 10 m test-range electric field strength height pattern by means of measuring the tangential electromagnetic fields on the cubic surface surrounding Bi-conical and Log-periodic antennas placed above the ground plane by using the differential electric and magnetic probe. The analysis frequency range is from 30 MHz to 1GHz, and the polarization...
In maritime mobile satellite communications, mechanically controlled tracking systems are used to compensate changes of antenna orientation due to changes of a ship attitude caused by waves or winds of the sea. Orientations of antennas on a ship are limited so that transmitted electromagnetic waves are not affected by structures on the ship. Thus it is allowed to transmit waves when a clearance angle...
Study of the radio propagation channel is essential to design a reliable wireless system, especially in the Body Area Network (BAN) which will be used for medicallhealthcare purposes. In the simulation of the BAN channel, various postures and motions of the human body should be examined for robustness. However, generating this motion data consumes time and is costly since experience with 3D animation...
In maritime mobile satellite communications, received satellite signal level varies due to direction and motion of a ship. Then sometimes the communications are interrupted, because the receiving satellite signal level decreases when the ship's body shadows the antenna. Thus it is important to evaluate how qualities of satellite communications vary during ship operations. However, precise temporal...
It is known that a reflected wave from an electromagnetic wave absorber on a wall of an anechoic chamber includes higher-mode diffracted waves. Our research group has studied higher mode diffracted waves from pyramidal wave absorber by measurements and simulations. Meanwhile, an evaluation method for anechoic chambers is defined by the CISPR16-1-4 Ed.3 standard. In this method, measured site voltage...
In this paper, results of an indoor experiment for 2.45 GHz dynamic wearable wireless body area network (WBAN) using multiport vector network analyzer is reported. Temporal changes of propagation characteristics for two human male subjects are measured for six antenna positions on-body simultaneously. Statistical characteristics and correlations between individual receiving points are reported.
On-body communication channels are of increasing interest as more and more wireless devices are wearable in medical, military and personal communication applications. Based on the previous study at 4.5GHz, this paper investigates reasons for time-varying fading of dynamic on-body channels. Antenna movements during action are categorized into intentional movement which can be controlled and unintentional...
Wireless patient monitoring using wearable sensors is a promising application. This paper provides stochastic channel models for wireless body area network (WBAN) on the human body. Parameters of the channel models are extracted from measured channel transfer functions (CTFs) in a hospital room. Measured frequency bands are selected so as to include permissible bands for WBAN; ultra wideband (UWB),...
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