A wireless power transfer system that employs a form of conductively coupled power transfer to transfer energy to deeply implanted devices.

One example discloses a first near-field device, including: a controller configured to establish a near-field communications link with a second near-field device; wherein the controller is configured to monitor a characteristic of the near-field communications link; wherein the controller is configured to select a first modulation encoding for transmitting a near-field signal if the characteristic is greater than a first characteristic threshold; and wherein the controller is configured to select a second modulation encoding for transmitting the near-field signal if the characteristic is less than the first characteristic threshold but greater than a second characteristic threshold.

In one embodiment, a Magnetic Resonance Imaging (MRI) apparatus includes: an RF coil configured to perform A/D conversion on a magnetic resonance (MR) signal received from an object and wirelessly transmit the MR signal; a main body configured to wirelessly receive the MR signal and generate a system clock; first communication circuitry configured to transmit the system clock by surface electric field communication using electric field propagation along a body surface of the object; and second communication circuitry provided in the RF coil and configured to receive the system clock transmitted by the surface electric field communication, wherein the RF coil is configured to operate based on the received system clock.

Provided are an ultrasonic human body communication method and a device thereof, the method including dividing serial information into blocks, and each information block includes modulation bits and index bits; each transmission frame is divided into multiple groups; performing an index modulation on the groups of each transmission frame, determining activated group sequence numbers; performing a digital modulation on the modulation bits of each information block, and mapping the digitally modulated modulation bits to activated groups; for the multiple information blocks processed in parallel, performing a parallel/serial conversion, a pulse shaping, and an ultrasonic conversion in sequence to obtain a transmission signal, and transmitting the transmission signal in a human body through a transmission frame; on a receiving node, receiving a received transmission signal propagated by the human body, and demodulating the received transmission signal to obtain the index bits and the modulation bits.

A plurality of frequency orthogonal signals are transmitted into a person. At least one of the plurality of frequency orthogonal signals is received at a receiving antenna or conductor. The received signal is measured. Characteristics of the received signal are used to establish a result related to that person.

An estimation method includes: transmitting transmission signals using M transmission antenna elements; receiving reception signals by N reception antenna elements; calculating, from the reception signals, a first matrix whose components are complex transfer functions indicating propagation characteristics between the transmission antenna elements and the reception antenna elements; estimating, using the first matrix, a position and an orientation of a living body relative to an estimation device; when the estimated position is in a first identification region and the estimated orientation is in a predetermined range from a first direction, identifying the living body based on time waveforms of the reception signals and a first training signal which is obtained in advance in the first identification region and corresponds to the living body; and adding, as an identification region for identifying the first living body identified, a new identification region based on an estimated position of the first living body identified.

A method for receiving a signal during an intra-body communication via a user carrying a terminal. The method includes, at the level of the terminal: receiving, from a communication device, a signal characterizing the fact that an approach gesture performed by the user toward the device has been performed between two times; detecting the time interval, between the two times, in which the amplitude of the signal is at a maximum; detecting, in the time interval, information determining whether or not the user has touched the device between the two times; and validating a transaction depending on the value of said detected information.

A method for receiving a signal during an intrabody communication via a user carrying a terminal. The method is performed by the terminal and includes: receiving a signal from a communication device, indicating that the user moved closer to the device between two instants; detecting, in the signal received, a first radio frame generated between the two instants, the first frame being at the same frequency as that of the signal received; detecting, in the signal received, a second radio frame generated between the two instants, the second frame being at a different frequency to that of the signal received; comparing the first frame to the second frame; and validating a transaction based on the presence or absence of information common to the first and second compared frames.

A method for recognizing a user carrying a terminal capable of receiving a radio signal coming from a device equipped with an antenna suitable for transmitting the signal. The signal is intended to be transmitted between the device and the terminal by using electromagnetic wave conduction capacities of the body of the user when at least one part of his/her body is in the vicinity of the antenna. When the user makes a characteristic movement, to move the part of his/her body close to the antenna, the device transmits a characteristic signal of the movement. The method includes: receiving a signal coming from the device; generating a characteristic datum of the movement; obtaining at least one signature; comparing the characteristic datum with the signature; and depending on the results of the comparison, recognizing the user.

Provided are a human body communication device and an operating method of the same. The human body communication device according to an embodiment of the inventive concept includes a first electrode, a second electrode, a transmitting circuit, a receiving circuit, a ground electrode, and a switch. The transmitting circuit generates a first signal in a transmitting mode and transmits the first signal to the first electrode. The receiving circuit receives a second signal from the first electrode in the receiving mode. The receiving circuit includes a differential amplifier that amplifies a difference between a voltage level of a first input terminal depending on the second signal and a voltage level of a second input terminal. The switch electrically connects the second electrode and the ground electrode in the transmitting mode, and electrically connects the second electrode and the second input terminal in the receiving mode.