Abstract: Disclosed is a charging method of a multi-node wireless charging system using magnetic field communication capable of effectively charging a plurality of nodes using the magnetic field communication. The magnetic field communication protocol for wireless charging is prepared and thus, an appropriate wireless charging device may be selected and charged for an appropriate time. The wireless charging method of the present invention includes: transmitting an association request frame; receiving an association response frame from the wireless charging devices; transmitting a charging requirement request frame; receiving a charging requirement response frame from the wireless charging devices; transmitting a charging preparation request frame; and transmitting power during a receiving period of the charging preparation response frame for the charging preparation request frame.

Abstract: This invention defines management protocols for wireless power transfer to multiple devices in Multi-device Wireless Power Management System. Various functions of Multi-device Wireless Power Management System are justified from this invention. The WPT frames and messages which work between the management block of a charger and the management block or the coupler block of a device, or the coupler block of a charger are defined as well to execute various functions. Also the procedures for each functionality are described based on its frames and messages.

Abstract: This invention defines management protocols for wireless power transfer to multiple devices in Multi-device Wireless Power Management System. Various functions of Multi-device Wireless Power Management System are justified from this invention. The WPT frames and messages which work between the management block of a charger and the management block or the coupler block of a device, or the coupler block of a charger are defined as well to execute various functions. Also the procedures for each functionality are described based on its frames and messages.

Abstract: A wireless multi charging method and system are disclosed. The wireless charging method selects a portion of mobile devices located in a charging region as a group, and provides energy for wireless charging to the selected group of mobile devices. Accordingly, group charging is possible, and thus it is also possible to selectively charge mobile devices which allow charging.

Abstract: A magnetic field communication method is provided for managing node with low power consumption which enhances performance and efficiency of a magnetic field area network in the low frequency region. The magnetic field communication method for managing node with low power consumption of the present invention is accomplished in a low-frequency wireless network that is comprised of a MFAN-C and at least one MFAN-N wherein a physical layer is comprised of a preamble, a header, and a payload, and the preamble is comprised of a wake-up sequence and a synchronization sequence. The wake-up sequence is only added to the preamble of the frame that is transmitted from the MFAN-C when the MFAN-N is being activated from the hibernation mode. The wake-up sequence is modulated using ASK modulation, and the synchronization sequence is modulated using BPSK modulation.

Abstract: Magnetic field communication methods and apparatuses are performed by the coordinator and node of a magnetic field area network, respectively. The method which is performed by the coordinator includes: (a) sending a request packet requesting association with a network, disassociation from a network, network association state checking, data transmission, or group address setting, (b) receiving response packets, (c) selecting one or more response packets from among the received response packets, (d) sending a response acknowledgement packet to nodes corresponding to the selected response packets, (e) receiving response packets resent by nodes which have not received the sent response acknowledgement packet, (f) selecting one or more response packets from among the response packets received at (e), and (g) sending a response acknowledgement packet to nodes corresponding to the response packets selected at (f).

Abstract: The present invention relates to a demodulator for simultaneous multi-node receiving and a method therof; and, more particularly, a demodulator in a wireless communication system for receiving signals from multi nodes simultaneously and a method thereof. In accordance with the aspect of the present invention, there is provided a demodulator for simultaneous multi-node receiving which comprises: a clock generator for generating a pair of CW signals and a pair of demodulating modules, wherein the demodulating modules comprise a mixer for multiplying received signals and one of the CW signals, an integrator for integrating multiplied signal and data operating unit for calculating variation result of integrated signal at every certain symbol duration and deciding output data in accordance with the variation result.

Abstract: Disclosed is a charging method of a multi-node wireless charging system using magnetic field communication capable of effectively charging a plurality of nodes using the magnetic field communication. The magnetic field communication protocol for wireless charging is prepared and thus, an appropriate wireless charging device may be selected and charged for an appropriate time. The wireless charging method of the present invention includes: transmitting an association request frame; receiving an association response frame from the wireless charging devices; transmitting a charging requirement request frame; receiving a charging requirement response frame from the wireless charging devices; transmitting a charging preparation request frame; and transmitting power during a receiving period of the charging preparation response frame for the charging preparation request frame.

Abstract: Disclosed herein is a wireless communication method for a magnetic field communication network. The wireless communication method is performed by a coordinator on the magnetic field communication network. The wireless communication method includes transmitting a request signal used to request response to each of sensor nodes; selecting any one of response signals received from the sensor nodes; transmitting an acknowledgement signal to a sensor node corresponding to the response signal; selecting any one of response signals transmitted again from sensor nodes which did not receive the acknowledgement signal; and transmitting an acknowledgement signal to a sensor node corresponding to the selected response signal.

Abstract: The present invention relates to a method for configuring a physical layer of a low frequency band based on wireless magnetic field communication, and a computer-readable recording medium including a program for executing the method. The method supports the proper packet format, coding mode, and modulation mode between a master and a slave in order to enable wireless communication in variable data rate or coding modes depending on a peripheral environment in a low frequency band based on wireless magnetic field communication which is applied to a difficult environment. The method of the invention is characterized by changing the data rate and the coding mode of a payload field within a preset range depending on the peripheral communication environment, wherein the payload field is included in the request and response frames between the master and the slave.

Abstract: A magnetic field communication method is provided for managing node with low power consumption which enhances performance and efficiency of a magnetic field area network in the low frequency region. The magnetic field communication method for managing node with low power consumption of the present invention is accomplished in a low-frequency wireless network that is comprised of a MFAN-C and at least one MFAN-N wherein a physical layer is comprised of a preamble, a header, and a payload, and the preamble is comprised of a wake-up sequence and a synchronization sequence. The wake-up sequence is only added to the preamble of the frame that is transmitted from the MFAN-C when the MFAN-N is being activated from the hibernation mode. The wake-up sequence is modulated using ASK modulation, and the synchronization sequence is modulated using BPSK modulation.

Abstract: Magnetic field communication methods and apparatuses are performed by the coordinator and node of a magnetic field area network, respectively. The method which is performed by the coordinator includes: (a) sending a request packet requesting association with a network, disassociation from a network, network association state checking, data transmission, or group address setting, (b) receiving response packets, (c) selecting one or more response packets from among the received response packets, (d) sending a response acknowledgement packet to nodes corresponding to the selected response packets, (e) receiving response packets resent by nodes which have not received the sent response acknowledgement packet, (f) selecting one or more response packets from among the response packets received at (e), and (g) sending a response acknowledgement packet to nodes corresponding to the response packets selected at (f).

Abstract: The present invention relates to a demodulator for simultaneous multi-node receiving and a method therof; and, more particularly, a demodulator in a wireless communication system for receiving signals from multi nodes simultaneously and a method thereof. In accordance with the aspect of the present invention, there is provided a demodulator for simultaneous multi-node receiving which comprises: a clock generator for generating a pair of CW signals and a pair of demodulating modules, wherein the demodulating modules comprise a mixer for multiplying received signals and one of the CW signals, an integrator for integrating multiplied signal and data operating unit for calculating variation result of integrated signal at every certain symbol duration and deciding output data in accordance with the variation result.

Abstract: A wireless communication system for managing an underground facility includes: at least one sensor node attached to the underground facility configured to transmit a sensing signal via magnetic field communication after detecting the status information of the underground facility in accordance with a driving signal, the driving signal comprising a wake-up signal; and an information collection device configured to: transmit the driving signal to the sensor node; collect the sensing signal transmitted from the sensor node; and transmit the collected information to a monitoring system via short-range wireless communication.

Abstract: A joint detection-decoding receiver using a multistage parallel interference canceller for selectively estimating a partial codeword corresponding to a state transition (branch) is disclosed. The JDD receiver of the DS-CDMA system includes a PIC that employs a state sequence to selectively carry out a symbol estimation of a partial codeword corresponding to the branch so as to reduce complexity and a calculation load as well as maintaining a high performance of the receiver according to the joint detection-decoding.

Abstract: A joint detection-decoding receiver using a multistage parallel interference canceller for selectively estimating a partial codeword corresponding to a state transition (branch) is disclosed. The JDD receiver of the DS-CDMA system includes a PIC that employs a state sequence to selectively carry out a symbol estimation of a partial codeword corresponding to the branch so as to reduce complexity and a calculation load as well as maintaining a high performance of the receiver according to the joint detection-decoding.