KR102133584B1 - Management system electric vehicle charging station utilizing PLC - Google Patents

Abstract

Provided is an in-band communication capable of simultaneously performing wireless power transmission and magnetic field communication using the same frequency band and an electric vehicle charging station management system using a PLC.

Description

Management system electric vehicle charging station utilizing PLC

The present invention relates to an electric vehicle charging station management system, and more particularly, to an electric vehicle charging station management system using an in-band communication and PLC that can simultaneously perform wireless power transmission and magnetic field communication using the same frequency band.

A wireless charging system using a magnetic induction phenomenon has been used as a wireless power transmission technology that wirelessly transfers energy.

For example, an electric toothbrush or a wireless razor is charged with the principle of electromagnetic induction, and recently, wireless charging products have been released that can charge mobile devices such as mobile phones, PDAs, MP3 players, and notebook computers using electromagnetic induction. .

However, the magnetic induction method of inducing current through a magnetic field from one coil to another coil is very sensitive to the distance and the relative position between the coils, so that the transmission efficiency drops rapidly even if the distance between the two coils is slightly distorted or distorted. Accordingly, this self-induction charging system has a weakness that it can be used only at a short distance of several centimeters or less.

On the other hand, U.S. Patent 7,741,735 discloses a non-radiation type energy transmission method based on attenuation wave coupling of a resonance field. This is because two resonators having the same frequency do not affect other non-resonators around, but they have a tendency to couple with each other, and have been introduced as a technology that can transmit energy over a long distance compared to conventional electromagnetic induction. .

The present invention has been devised in the technical background as described above, and an object of the present invention is to provide an in-band communication method capable of simultaneously performing wireless power transmission and magnetic field communication using the same frequency band.

The present invention provides a physical layer and a MAC layer protocol for in-band communication of a wireless power transmission system for wireless charging of multiple devices.

A communication method of a wireless power transmission system according to the present invention is a communication method of a wireless power transmission system for wireless charging of multiple devices, wherein the wireless power transmission system includes wireless power transmission to devices, charging, and devices in a communication area. A base station that manages connection and disconnection of data, transmission and reception times of data and wireless power transmission in the wireless power transmission network; And a device excluding the base station constituting the wireless power transmission network, comprising a plurality of nodes that are devices receiving wireless power from the base station, wherein the wireless power transmission system has a center frequency between 80 kHz and 400 kHz. Performs wireless power transmission and magnetic field communication using one frequency band, and wireless power through a superframe composed of a request period, a response period, and a spontaneous period as temporal components. Performs transmission and magnetic field communication.

According to the present invention, wireless power transmission and data transmission of several kbps are possible based on a network formed within a distance of several meters.

1 is a wireless power transmission system
2 is a mobile device
3 is a household appliance
4 is an iWPTN superframe structure for MFC
5 is an iWPTN superframe structure for WPT
Figure 6 iWPTN structure
7 is a UID structure
8 is an iWPTN-B state diagram
9 is an iWPTN-D state diagram
10 is a PHY layer frame format
11 is a preamble format
12 is a MAC layer frame format
13 is a control field frame format
14 is a request frame format
15 is a response frame format
16 is a data frame format
17 is a response confirmation frame format
18 is a data confirmation frame format
19 shows the format of the payload of the request frame
20 is a connection request block format
Figure 21 is a separation request block format
22 is a connection state request block format
23 is a data request block format
24 is a group ID setup request block format
25 is a block diagram of a power transmission request
26 is a block diagram of a power transmission start request.
27 shows the payload format of the response frame
28 is a connection response block format
29 is a separate response block format
30 is a connection status response block format
31 is a data response block format
32 is a group ID setup response block format
33 is a power transmission response block format
Fig. 34 shows the payload format of a data frame
35 shows the payload format of the confirmation frame
Figure 36 is a connection response confirmation block format
37 is a separate response confirmation block format
Figure 38 is a connection status response confirmation block format
39 is a data response confirmation block format
40 is a group ID setup response confirmation block format
41 is a PSFI of a WPT response section
Figure 42 PS PS Beacon Format
Fig. 43 shows the frame control of the PS beacon
44 is a PSF of a WPT response section
Fig. 45 Frame control of PSF
Figure 46 is BPTRq format
47 shows BPTRs format
48 is a connection procedure
49 is a separation procedure
50 is a connection status check procedure
51 is a data transmission procedure of a response section
52 is a data transmission procedure in an autonomous section
53 is a group ID setup procedure
54 is a wireless power transmission procedure
55 is a battery discharge procedure
56 is an envelope waveform
57 is a BPSK-modulated signal
58 shows the ASK-modulated signal
59 is a WPT signal

3 Terms and definitions

The following terms and definitions are used herein.

3.1 Wireless power transfer (WPT)

Mechanisms for devices with sufficient power to wirelessly transmit them to other devices

3.2 Wireless power transfer network (WPTN)

A network that is a system that transmits wireless power to the device under consideration based on recognizing the wireless power transmission status through wired/wireless communication.

3.3 Magnetic field communication (MFC)

Wireless communication using magnetic field

3.4 In-band wireless power transfer network (iWPTN)

A wireless power transmission network that uses one frequency band for wireless power transmission and magnetic field communication.

3.5 In-band wireless power transmission network-Base Station (iWPTN-B)

A system that manages the transmission/reception time of wireless power transmission to devices, connection and disconnection of devices in charging and communication areas, and data wireless power transmission in iWPTN.

3.6 In-band wireless power transmission network-device (iWPTN-D)

A device other than the base station forming a network in iWPTN, which receives wireless power from the base station.

3.7 Magnetic field area network (MFAN)

A wireless network that provides wireless communication based on reliable in-band magnetic field communication using a magnetic field

4 Symbols and abbreviations

The following abbreviations are used in this specification.

ABNR Abnormal

ARq Association Request

ARs Association Response

ARA Association Response Acknowledgement

ASC Association Status Check

ASK Amplitude Shift Keying

ASRq Association Status Request

ASRs Association Status Response

ASRA Association Status Response Acknowledgement

BPSK Binary Phase Shift Keying

BPTRq Battery-out Power Transfer Request

BPTRs Battery-out Power Transfer Response

MFC Magnetic Field Communication

CRC Cyclic Redundancy Check

DA Data Acknowledgement

DaRq Disassociation Request

DaRs Disassociation Response

DaRA Disassociation Response Acknowledgement

DRq Data Request

DRs Data Response

DRA Data Response Acknowledgement

FCS Frame Check Sequence

GSRq Group ID Set-up Request

GSRs Group ID Set-up Response

GSRA Group ID Set-up Response Acknowledgement

HCS Header Check Sequence

LSB Least Significant Bit

MAC Media Access Control

NRZ-L Non-Return-to-Zero Level

PHY Physical Layer protocol

PTRq Power Transfer Request

PTRs Power Transfer Response

PS Power Status

PSF Power Status Feedback

PSFI Power Status Feedback Interval

RA Response Acknowledgement

RR Response Request

SIFS Short Inter Frame Space

TDMA Time Division Multiple Access

UID Unique Identifier

5 Overview

iWPTN is a wireless network that can transmit power wirelessly and exchange the necessary data and control commands through the MFC system using the same frequency used in wireless power transmission. Due to the characteristics of the magnetic field and the power level that satisfies the regulations, the communication area is wider than the power transmission area. The necessary information is exchanged based on the communication link supported by MFAN, and iWPTN-B performs scheduling to provide efficient WPT.

The MFC system in iWPTN has a center carrier frequency band of 30KHz to 300KHz, which is the same as the frequency band of wireless power transmission. This can be implemented at low cost using a simple and robust modulation method such as BPSK, and a low error rate can be obtained. It is also robust against noise using dynamic encoding methods such as Manchester or NRZ-Lem. It provides data transfer rates of several kbps within a few meters. In WPT, a non-modulated sinusoidal signal is used to increase WPT efficiency.

iWPTN uses a simple and efficient network topology, such as a star topology, to reduce power consumption. In addition, dynamic address allocation is used for small packet size and efficient address management. Depending on the wireless charging environment, adaptive link quality control using variable transmission rate and encoding method is used. Nodes of iWPTN are divided into iWPTN-B and iWPTN-D according to their functions. There is only one iWPTN-B in one iWPTN network, and a number of iWPTN-D nodes form a network around iWPTN-B. iWPTN-B manages connection and disconnection of iWPTN-D. iWPTN uses a time division multiple access (TDMA) method for data transmission and reception. When iWPTN-D joins an iWPTN network managed by iWPTN-B, iWPTN-B allocates a time slot for iWPTN-D transmission according to iWPTN-D request and iWPTN-B's decision. .

1, iWPTN-B and iWPTN-D may be located indoors. When iWPTN-B receives data related to wireless power transmission such as ID or battery information from iWPTN-D, it collects the received data and calculates required factors such as the number of time slots for wireless power transmission or the power transmission order. . iWPTN-B transmits control data for managing iWPTN to iWPTN-D.

iWPTN is applied in various industries. It is applied to electric devices that require electric power to perform functions. For some applications, it may also lead to improved functionality by wirelessly powering the exterior of the device. These devices solve problems such as the life of the battery and the structure for storing the battery.

For example, iWPTN provides a ubiquitous charging environment for mobile devices where the battery is always a problem as the usage time increases (FIG. 2). For the home appliance, the complicated wires and plugs are removed so that the home appliance is arranged and the desired decoration is obtained (FIG. 3).

6 Network components

6.1 General

The main components of iWPTN are time and physical components. The time element indicates a superframe composed of a request period, a response period, and an autonomous period, and a physical element refers to a network of iWPTN-B and iWPTN-D. The most basic element of a physical element is a node. Nodes are divided into two types, one is iWPTN-B, which manages the network, and the other is iWPTN-D, which communicates with iWPTN-B.

4 to 6 show structures of superframes and networks, which are time and physical elements, respectively. The first node to be determined in iWPTN is iWPTN-B, and the superframe is started by iWPTN-B sending a request packet during the request period. iWPTN-B manages association, disassociation, release and scheduling of iWPTN-D. One iWPTN uses one channel, and consists of only one iWPTN-B and the other iWPTN-D using the channel. Of the nodes in iWPTN, the remaining nodes except iWPTN-B are iWPTN-D. Depending on the role, any node can be iWPTN-B or iWPTN-D. Basically, peer-to-peer (P2P) connection between iWPTN-B and iWPTN-D is considered.

6.2 Time Factor

The time element used in iWPTN is a TDMA time slot. iWPTN-B manages the iWPTN-D group that transmits data in the response section, and the time slots are self-arraged by the selected iWPTN-D.

6.2.1 MFC time elements

The superframe of iWPTN for magnetic field communication is composed of a request section, a response section, and an autonomous section, as shown in FIG. 4, and the length of the request and response section is variable. Superframe is started by iWPTN-B sending RR packet in the request section.

The RR packet has information on which iWPTN-D will transmit the response packet during the response period, and the selected iWPTN-D can transmit the response packet in the response period according to the RR packet information.

6.2.1.1 Request section

In the request section, iWPTN-B transmits an RR packet containing information used by iWPTN-D to send a response packet in the response section.

6.2.1.2 Response section

In the response section, iWPTN-D may transmit a response packet according to the RR packet received from iWPTN-B. The response section is divided into a number of time slots according to the number of iWPTN-Ds selected in iWPTN. The length of each time slot may vary depending on the length of the response frame and acknowledgment (ACK). When the iWPTN-B schedules the response section, the slot number is determined according to the order of divided time slots. Otherwise, the slot number is 0. iWPTN-B allocates a time slot for use of a response section to each iWPTN-D or a specific group, and nodes of the assigned group independently transmit data frames in the response section.

6.2.1.3 Autonomous section

The autonomous section starts when no node transmits a response packet for a certain period of time. During this period, the node can transmit data without requesting iWPTN-B. This period is maintained until iWPTN-B transmits the request packet.

6.2.2 WPT time factor

The superframe for the WPT of iWPTN is shown in FIG. 5, which consists of a request section, a response section, and an autonomous section, and the length of each section is variable. The superframe starts with iWPTN-B sending a PTRq packet to iWPTN-D in the request interval. When iWPTN-D receives a packet, it sends a PTRs packet in response. Based on the PTRs packet, iWPTN-B transmits a PTS packet including scheduling information for iWPTN-D to receive WPT during the response period, and the selected iWPTN-D PS from iWPTN-B during the power state feedback period The PSF packet is transmitted in response to the beacon.

6.2.2.1 Request section

In the request section, iWPTN-B transmits an RR packet including WPT scheduling information. The iWPTN-D receiving the RR packet prepares to receive the WPT from the iWPTN-B according to the scheduling information.

6.2.2.2 Response section

In the WPT response section, iWPTN-B provides WPT to iWPTN-D according to the scheduling order. The response period may be divided into multiple time slots according to the number of iWPTN-Ds selected in iWPTN. The length of each time slot is variable according to the length of the WPT section. When iWPTN-B schedules all time slots in the response period, the slot number is determined by the order of divided time slots. Otherwise, the slot number is 0. iWPTN-B allocates a time slot to iWPTN-D or a specific group. According to the scheduling order, one iWPTN-D receives WPT, or all iWPTN-Ds in the assigned group simultaneously receive wireless power. Compared to the response section of the magnetic field communication, the WPT response section has a PSFI. The variable length PSFI is for rapid power status update and occurrence of an abnormal situation.

6.2.2.3 Autonomous section

The autonomous period starts when all PSF packets from iWPTN-D considered in the last time slot of all response periods are identified. In this section, the node can transmit the EPTq packet even if there is no iWPTN-B request. When iWPTN-B receives the EPTq packet, iWPTN-B transmits the EPT packet and then provides WPT for a certain period of time. This period is maintained until iWPTN-B transmits the request packet.

6.2.3 Network activation

iWPTN's superframe is divided into a request section, a response section, and an autonomous section. iWPTN-B and iWPTN-D in iWPTN operate as follows in each section.

6.2.3.1 Request packet transmission within the request section

In the request period, iWPTN-B transmits an RR packet to iWPTN-D. Based on this, the iWPTN-D receiving the RR packet determines whether to transmit the response packet during the response period. iWPTN-B may cause the iWPTN-D group to transmit during the response period.

6.2.3.2 Response packet transmission within the response section

The iWPTN-D selected by iWPTN-B may transmit a response packet in the response section. When iWPTN-D transmits a response packet in a response section, iWPTN-B receiving the response packet transmits an RA packet. The iWPTN-D, which has not received the RA packet, transmits a response packet every time slot until receiving the RA packet from the iWPTN-B.

6.2.3.3 Wireless power transmission within the response section

iWPTN-D selected by iWPTN-B receives WPT during the response period. After each time slot, there is a PSFI for quick power status updates and abnormal conditions. During the WPT, when the iWPTN-D receives the PS beacon in the PSFI, it sends a PSF packet informing the PS beacon in the PSFI of the updated power state to the iWPTN-B. When an abnormal situation is detected by iWPTN-B, all iWPTN-Ds are notified by PSFI by iWPTN-B. If iWPTN-D recognizes the error by receiving the PS beacon, it waits until it receives a request from iWPTN-B.

6.2.3.4 Data packet transmission in autonomous section

The autonomous period starts when the iWPTN-D does not receive power for a certain time period and does not transmit a response packet, and this period is maintained until the iWPTN-B transmits an RR packet. In the autonomous section, iWPTN-D can transmit data without requesting iWPTN-B.

6.2.3.5 Wireless power transmission in autonomous section

The autonomous period starts when all PSF packets from iWPTN-D considered in the last time slot of all response periods are confirmed, and this period is maintained until iWPTN-B transmits an RR packet. In the autonomous section, iWPTN-D can transmit an EPTq packet without the request of iWPTN-B. When iWPTN-B receives an EPTq packet, iWPTN-B transmits an EPTs packet in response to the EPTq packet, and then provides WPT for a certain period of time.

6.3 Physical elements

The physical elements constituting iWPTN are divided into iWPTN-B and iWPTN-D, and all iWPTN-D are connected to iWPTN-B (i.e., the central connecting device). Nodes, which are basic components, are divided into iWPTN-B and iWPTN-D according to their roles. iWPTN-B manages the entire iWPTN, and there is only one iWPTN-B in one network. iWPTN-B manages iWPTN-D by sending RR packets. iWPTN-D must send a response packet according to the management of iWPTN-B. iWPTN may be configured as shown in FIG. 6.

6.3.1 iWPTN-B

iWPTN-B is the node that manages iWPTN; Only one iWPTN-B exists in one network, and WPTN-D is managed and controlled by RR packets.

6.3.2 iWPTN-D

iWPTN-D is a node existing in iWPTN (excluding iWPTN-B), and there can be up to 65,519 iWPTN-D per network. iWPTN-D transmits a response packet according to the RR packet transmitted by iWPTN-B.

6.4 Address elements

To identify the iWPTN-D, iWPTN uses address systems such as iWPTN ID, UID, group ID, node ID and charging ID.

6.4.1 iWPTN ID

iWPTN has a unique ID to identify the network to other networks; This value can be duplicated with other iWPTNs and is maintained as long as iWPTNs exist. This value is defined by the user to distinguish the network.

6.4.2 UID

UID is a unique identifier consisting of 64 bits; This consists of the group ID, the IC manufacturer's code, and the serial number of the IC manufacturer. iWPTN-D is identified by UID.

7 shows the UID structure.

6.4.3 Group ID

iWPTN-D can be grouped by application. The Group ID is an identifier for iWPTN-Ds grouped in the network. iWPTN-B may request a response from a specific iWPTN-D group to reduce packet collision. Some group IDs are designated as shown in Table 1. This value is defined by the user to distinguish the groups.

[Table 1] Reserved group ID

6.4.4 Node ID

Node ID is an identifier used in place of UID to identify a node and has a 16-bit address assigned by iWPTN-B. Some node IDs are designated as shown in Table 2.

[Table 2] Reserved node ID

6.4.5 WPT ID

WPT ID is an ID used during WPT. This ID has an 8-bit address assigned by iWPTN-B for quick communication during WPT. This ID may be assigned to iWPTN-D during the request period immediately before the WPT of the response period. Some WPT IDs are designated as shown in Table 3.

[Table 3] Reserved charging ID

7 Network status

7.1 General

In iWPTN, iWPTN-D can be activated in network configuration, network connection, response transmission, data transmission, network separation, network release, and wireless power transmission.

7.2 Network Configuration

iWPTN-B configures the network by sending a request packet to iWPTN-D in the request section. The request packet includes an iWPTN ID so that the iWPTN-D can identify the network to which it is connected. The minimum section of the network means while iWPTN-B is present, and consists of only the request section and the autonomous section.

7.3 Network connection

When the iWPTN-B transmits the ARq packet in the request section, the iWPTN-D checks the received packet and, if the ARq packet for the desired iWPTN, transmits the ARs packet to the iWPTN-B in the response section. iWPTN-B receives ARs packets and sends ARA packets to iWPTN-D. The network connection of iWPTN-D is completed when an ARA packet is received from iWPTN-B.

7.4 Network Separation

iWPTN-D connected to iWPTN can be separated by iWPTN-B's request or by itself. iWPTN-B can transmit DaRq packets to iWPTN-D for forced separation according to the current network condition. In the case of spontaneous separation due to a shutdown or a network area, iWPTN-B can know the connection status of iWPTN-D by responding to ASRq from iWPTN-B.

7.5 Data transmission

When iWPTN-B sends a DRq packet to iWPTN-D in the request section, iWPTN-D sends a DRs packet to iWPTN-B according to the requested data type. Upon receiving the DRs packet, iWPTN-B sends the DRA packet to iWPTN-D, and when iWPTN-D receives the DRA packet, data transmission is completed.

7.6 Wireless power transmission

When iWPTN-B sends a PTRq packet to iWPTN-D in the request period, iWPTN-D transmits a PTRs packet in the response period. Based on the information in the PTRs packet, iWPTN-B schedules a time slot for WPT, and transmits a PTS packet including scheduling information to the request section. iWPTN-D receives WPT from iWPTN-B in the response section according to the scheduling order. During each time slot, WPT may be provided for one iWPTN-D or group. After each iWPTN-D or group receives the WPT, there is a PSFI for quick power status update. When iWPTN-D receives a PS beacon in PSFI from iWPTN-B, it sends a PSF packet only when iWPTN-B requests the packet. After confirming the PSF packet, iWPTN-B provides WPT to iWPTN-D in the next slot. During WPT, if iWPTN-B detects an error, WPT is stopped. When PSFI is started, iWPTN-B notifies the other iWPTN-D of the detection of the error by sending a PS beacon. When the iWPTN-B receives the PSF packet from the last iWPTN-D or the last group in the last time slot of the response period, WPT is completed.

7.7 Battery-out

When iWPTN-D in the battery discharge state enters iWPTN, power is received during the response period even when scheduling is not considered. After receiving the power required to perform the basic functions of MFC, the power is stopped. During the autonomous period, power is additionally received by sending a BPTRq packet. When iWPTN-D receives power above the threshold, it stops receiving power and waits for a request period to join iWPTN.

7.8 Network release

iWPTN release is divided into normal release by request of iWPTN-D and abnormal release by unexpected situation. Normal release refers to the case of releasing the network by sending DaRq packets to all iWPTN-Ds by iWPTN-B's decision. Abnormal release is due to iWPTN-B's shutdown or out of network area.

7.9 iWPTN node status

iWPTN node state includes iWPTN-B state and iWPTN-D state. Specifically, the iWPTN-B state can be divided into a standby state, a packet analysis state, a packet generation state, and a power transfer state, and the iWPTN-D state Is a hibernation state, an activation state, a standby state, a packet analysis state, a packet generation state, a mute state, and a power reception state. (power receiving state).

7.9.1 iWPTN-B Status

The iWPTN-B state is in a standby state when the power is turned on. In the standby state, when the COMM command system sends an RR packet or a superframe is started, the iWPTN-B state is a packet generation state, and the iWPTN-B sends an RR packet to iWPTN-D. The next iWPTN-B state returns to the c-standby state (see path 4 in FIG. 8). When iWPTN-B receives a packet (response or data packet) from iWPTN-D, the iWPTN-B state becomes a packet analysis state during carrier detection in the standby state (see path 1 in FIG. 8). If the destination ID of the received packet and the node ID of the iWPTN-B are the same, the iWPTN-B state is a packet generation state, and the iWPTN-B generates an RA or DA packet in the packet generation state and sends it to the iWPTN-D (FIG. See path 1 in 8.). Next, the iWPTN-B state returns to the standby state (see path 4 in FIG. 8). On the other hand, if there is an error in the data packet, the iWPTN-B state immediately returns to the standby state (see path 3 in FIG. 8). In the packet analysis state, if there is an error in the received response packet, or if the destination ID of the received response packet and the node ID of iWPTN-B do not correspond, iWPTN-B regenerates the RR packet in the packet generation state to generate iWPTN-D And return to the standby state (see path 2 in FIG. 8). When this failure is repeated, the operation of the packet analysis state is repeated as many times as necessary (up to N times). In the (N+1)th operation, the state of iWPTN-B returns from the packet analysis state to the standby state (see path 2 in FIG. 8).

For WPT, when the superframe is started, the iWPTN-B state becomes a packet generation state, sends a PTRq packet, and returns to a standby state after sending the packet (see Route 4 in FIG. 8). Once the iWPTN-B receives the PTRs packet, it enters the packet analysis state (see path 1 in FIG. 8). After confirming the packet, the packet is generated and a PTS packet including scheduling information is generated (see path 5 in FIG. 8). After sending the PTS packet, the iWPTN-B state becomes a power transmission state for providing WPT to the first scheduled iWPTN-D or group (refer to Route 5 in FIG. 8 for the following description). When PSFI is started, the iWPTN-B state returns from the power transmission state to the packet generation state. PSFI is started and all PSW beacons are sent to iWPTN-D, and then a standby state is received to receive PSF packets from iWPTN-D. Upon receiving the PSF packet, it returns to the packet analysis state. When the PSF packet is confirmed, the power is transmitted to provide WPT to the next iWPTN-D or group. The path from the power transmission state to the packet analysis state is repeated until all iWPTN-Ds receive the WPT. When the PSF packet is confirmed in the packet analysis state, the PWR system returns to the standby state when the shutdown command is issued. If an error occurs, it returns to the standby state. In the battery discharge state, a BPTRq packet is received from iWPTN-D, and iWPTN-B goes from a packet analysis state to a packet generation state. After sending the BPTRs packet, the iWPTN-B state becomes a power transmission state. When the MFC system commands or the superframe starts, the packet is generated and an RR packet is generated (refer to path 4 in FIG. 8). The iWPTN-B state diagram is shown in FIG. 8.

7.9.2 iWPTN-D status

The iWPTN-D state is a power saving state when the power is turned on. In the power saving state, when a wake-up sequence is detected, it is activated (see path 1 in FIG. 9 for description below). The wake-up sequence is defined later in 8.1. When the iWPTN-D receives the RR packet, the iWPTN-D state becomes a packet analysis state, and the iWPTN-D analyzes the received RR packet. If the destination ID and iWPTN-D ID (group ID and node ID) of the RR packet match, the iWPTN-D status becomes the packet generation status, and iWPTN-D sends the response packet to iWPTN-B and waits for the iWPTN-D status. State (see path 3 in FIG. 9). Otherwise, it returns to the power saving state (see path 2 in FIG. 9).

During carrier detection in the standby state, the iWPTN-D state goes into a power saving state when it receives its own RA packet (see path 1 in Fig. 9), or the packet generation state when the MFAN-N receives an RA packet from another node (See path 2 in FIG. 9). If the slot number is not allocated in the standby state and the timeout period ends, the iWPTN-D state becomes a power saving state (refer to path 1 in FIG. 9), and when the slot number is allocated and the timeout period ends (up to N times continuously) ) iWPTN-D state is a packet generation state (see path 1 in FIG. 9). However, when the slot number is allocated and the N+1th timeout period ends, the battery enters a power saving state (see path 1 in FIG. 9). The slot number is allocated, and if the iWPTN-D fails to receive the RA packet during the timeout period, it enters the packet generation state from the standby state (see Route 1 in FIG. 9). Next, iWPTN-D regenerates and retransmits the response packet to iWPTN-B, and the iWPTN-D state becomes a packet generation state in a standby state (refer to path 3 in FIG. 9). The retransmission of the response packet is repeated as necessary (up to N times). In the N+1th timeout period, the standby state enters a power saving state (see path 1 in FIG. 9). When the RR packet is received while the iWPTN-D detects the carrier in the standby state, the packet is analyzed (see path 1 in FIG. 9).

When a system interruption occurs in the power saving state, the iWPTN-D state is activated (see path 3 in FIG. 9 for description below). When iWPTN-D receives data from the system, it is in a packet generation state. Next, iWPTN-D generates and sends a data packet to iWPTN-B, and the iWPTN-D state becomes a standby state. When the iWPTN-D receives the DA packet, it returns to the power saving state. Otherwise, the packet is generated and iWPTN-D retransmits data up to N times and returns to the standby state.

For WPT, when the iWPTN-D receives a PTRq packet during the request period, it enters a packet generation state and generates PTRs packets in response to the PTRq packets (see path 5 in FIG. 9). After transmitting the PTRs packet during the response period, it returns to the power saving state. When the iWPTN-D receives the PTS packet, it enters a packet analysis state. After confirming the packet, it is in a power transmission state or a power isolation state. If the next time slot is not the WPT order for iWPTN-D, the power is cut off from the packet analysis state in order not to interfere with other iWPTN-Ds that will receive WPT in the next time slot. When PSFI is started, iWPTN-D is activated. When the PS beacon is received from iWPTN-B, the packet analysis state is c. On the other hand, if the iWPTN-D is a WPT target node in the next time slot, the packet is analyzed and the power is transferred. When the power transmission ends, the device enters a standby state and receives a PS beacon from iWPTN-B. When a PS beacon is received from iWPTN-B, the packet is analyzed.

In the packet analysis state, when a request for a PSF packet is made, the packet is generated, and a PSF packet for rapid power state update is generated and sent to iWPTN-B. After transmitting the PSF packet, if the next time slot is not in the WPT order for iWPTN-D, the power is cut off so as not to interfere with other iWPTN-D to receive WPT in the next time slot. Otherwise, it is in a power transmission state for receiving WPT. This path from the power off state to the packet analysis state is repeated until the response period for the WPT ends. In this case, the state goes from the packet analysis state to the standby state.

When the detection of an error is recognized, this path is stopped. For the iWPTN-D receiving the current WPT, if a WPT interruption is detected during the current time slot (not after the slot has ended), it is switched to the standby state. Next, when the iWPTN-D receives the PS beacon, it enters a packet analysis state. When the PSFI is started, another iWPTN-D that is not currently receiving WPT is activated, and the packet is analyzed. In the packet analysis state, when the PS beacon is confirmed, it is recognized that the error has started.

When the iWPTN-D is a battery discharge, it maintains a power saving state, and collects a small amount of power for another scheduled iWPTN-D in the talk section (see path 4 in FIG. 9 for the following description). When the iWPTN-D detects the wakeup 2 signal, it enters the power saving packet analysis state and analyzes the PS beacon. After checking the PS beacon, it returns to the power saving state. When the response section ends, the power saving packet is generated and a BPTRq packet is generated. After sending the packet, it goes back to sleep and waits for the BPTRs packet. When the wake-up 2 signal is detected, the power saving packet is analyzed and the BPTRs packet is analyzed. After confirming the packet, it enters a power transmission state and receives WPT in an autonomous section. The iWPTN-D state diagram is shown in FIG. 9.

8 PHY layer

8.1 PHY layer frame format

8.1.1 General

This section describes the physical layer frame format. As shown in FIG. 10, the PHY layer format consists of three components: preamble, header, and payload. When transmitting the packet, the preamble is transmitted first, the header is followed, and finally the payload is transmitted. LSB is the first bit transmitted.

8.1.2 Preamble

As shown in Fig. 11, the preamble consists of two parts: a wake-up sequence and a synchronization sequence. The 8-bit wakeup sequence can be divided into two types, one for the general MFC and one for the general WPT. The wakeup 1 sequence for MFC consists of [0000 0000], and the wakeup 2 sequence for WPT consists of [1111 1111]. The 16-bit synchronization sequence consists of a 12-bit [000000000000] sequence and a 4-bit [1010] sequence. The wakeup 1 signal is included only in the preamble of the response packet of the request period, and the wakeup 2 signal is included only in the preamble of the PS beacon of the request period and the BPTRs packet of the autonomous period. The synchronization sequence is used for packet acquisition, symbol timing and carrier frequency measurement.

The preamble is encoded using type 0 defined in Section 7.1.3. The wakeup sequence is modulated with ASK, and the synchronization signal is modulated with BPSK.

8.1.3 Header

The header is included after the preamble to convey information about the payload. The header format is defined in ISO/IEC 15149.

8.1.4 Payload

The payload format is defined in ISO/IEC 15149.

8.1.5 Frame Check Sequence (FCS)

The payload uses CRC-16 FCS to check for errors. This sequence is defined in ISO/IEC 15149.

8.2 Coding and Modulation

8.2.1 Encoding

The MFC between iWPTN-B and iWPTN-D uses Manchester coding or NRZ-L coding. In addition, scrambling for coded data is used. Such encoding and scrambling is defined in ISO/IEC 15149.

8.2.2 Data rate and encoding type

Data rates and encoding for preamble/header and payload are defined in ISO/IEC 15149.

8.2.3 Modulation

The MFC between iWPTN-B and iWPTN-D uses ASK modulation or BPSK modulation. The details of rice paddy modulation are defined in ISO/IEC 15149.

8.2.4 Encoding and modulation process

The encoding and modulation process for the preamble, header and payload is defined in ISO/IEC 15149.

9 MAC layer frame format

9.1 General

The MAC frame of iWPTN consists of a frame header and a frame body. The frame header has information between iWPTN-D, and the frame body has data for transmission between iWPTN devices.

9.2 Frame Format

All MAC frames are composed of a frame header and a frame body as shown in FIG. 12.

1) Frame header: It consists of iWPTN ID, frame control, source node ID, destination node ID and sequence number. The frame header can be used for data transmission.

2) Frame body: consists of a payload containing data transmitted between iWPTN devices and an FCS to check for errors in the payload.

9.2.1 Frame header

The frame header has information for transmission/reception of frames and flow control.

9.2.1.1 iWPTN ID

As shown in FIG. 12, the iWPTN ID field is composed of 1 byte and is used to identify the network.

9.2.1.2 Frame control

The frame control field is composed of a frame type, an acknowledgment policy, a first fragment, a last fragment, and a protocol version, and this format is shown in FIG. 13.

The description of each field is as follows.

1) The frame type field is composed of 3 bits; Refer to Section 8.3 for frame type details.

2) The confirmation policy field consists of 2 bits; If the received frame is an acknowledgment frame, it indicates the policy of the acknowledgment frame, otherwise it indicates the policy of the acknowledgment frame for the destination node.

a) No acknowledgement: The destination node does not acknowledge the transmitted frame, and the originating node considers the transmission to be successful regardless of the transmission result. This method is used in frames transmitted in 1:1 or 1:N, and transmission does not require confirmation.

b) Single acknowledgment: The destination node receiving the frame sends an acknowledgment frame to the source node in response after SIFS. This confirmation policy can be used only for 1:1 transmission.

c) Multiple acknowledgments: The destination node receiving the frame sends an acknowledgment frame to multiple origin nodes in response after SIFS. This confirmation policy can only be used in 1:N transmission.

d) Data confirmation: The destination node receiving the data frame sends a confirmation frame to the source node in response after SIFS. This confirmation policy can be used only for 1:1 transmission.

3) The first fragment field is 1 bit; '1' indicates that the frame is the start of a request, response or data packet from a higher layer, and '0' indicates that it is not the start.

4) The last fragment field is 1 bit; '1' indicates that the frame is the end of a request, response or data packet from a higher layer, and '0' indicates that it is not the last.

5) The protocol version field is composed of 2 bits, and the size and position are fixed regardless of the protocol version of the system. The current value is 0, and is incremented by 1 whenever a new version is issued. When a node receives a packet version higher than its own, it discards it without notifying the source node.

6) Reserved: Reserved for future use.

9.2.1.3 Sequence number

The sequence number field is 8 bits long and indicates a frame sequence number. In the data frame, a sequence number between 0 and 255 is assigned as an increment counter for each packet, and when it reaches 255, it returns to 0 again.

9.2.2 Frame body

The frame body has a variable length and consists of a payload and FCS. Each payload has a different format according to the frame type of the frame control field, and FCS is used to check for errors in the frame.

9.2.2.1 Payload

The payload has data transmitted between iWPTN-B and each iWPTN-D, and the length is a variable value between 0 and 247.

9.2.2.2 Frame check sequence

FCS is 16 bits long and is used to check whether the frame body is received without error. It is generated using the following 16th order standard generator polynomial.

9.3 Frame type

The frame type is defined as four types of request frame, response frame, data frame and acknowledgment frame.

[Table 4] Frame type value

9.3.1 Request frame

The request frame is used when iWPTN-B sends an RR packet to a specific iWPTN-D in iWPTN in the request section or broadcasts information to all iWPTN-Ds. The request frame format is shown in FIG. 14. It should be noted that the confirmation policy when broadcasting the RR packet is no confirmation. The RR packet includes ARq, DaRq, ARsRq, DRq, PRRq, and the like.

9.3.2 Response frame

The response frame is used when iWPTN-D sends a response packet for the request of iWPTN-B in the response section. iWPTN-D sends a response packet a certain number of times until an acknowledgment packet is received in the response period.

The response frame format is shown in FIG. 15.

9.3.3 Data frame

Data frame is used when iWPTN-D sends data to iWPTN-B without request of iWPTN-B in autonomous section.

The data frame format is shown in FIG. 16.

9.3.4 Confirmation frame

The confirmation frame includes an RA frame and a DA frame. When iWPTN-B transmits an RR packet, iWPTN-D receiving an RR packet transmits a response packet and iWPTN-B receiving a response packet transmits an RA packet. The payload of the acknowledgment frame contains the response acknowledgment data of the received response packet. The iWPTN-B receiving the response packet responds to the iWPTN-D by sending an RA packet after SIFS of the response period. The DA frame is a confirmation frame for the received data packet. The iWPTN-B responds to the iWPTN-D that sent the data packet by sending a DA packet after SIFS of the autonomous period.

The response confirmation frame format is shown in FIG. 17 and the data confirmation frame format is shown in FIG. 18.

As shown in FIG. 18, the DA frame is composed of a frame header and a frame body. If the destination node ID is a node ID that has not joined with 0xFFFE, a UID field is included.

9.4 Payload Format

The payload format includes a request frame, a response frame, a data frame and an acknowledgment frame.

9.4.1 Request frame

As shown in FIG. 19, the payload of the request frame consists of a group ID, a request code, a length, and one or more request blocks. A group ID of 0xFF indicates that iWPTN-B requests all iWPTN-D groups to respond.

9.4.1.1 Group ID

The group ID field consists of 1 byte and is used to send RR packets to a specific group. See Section 6.4.3 for details of the group ID.

9.4.1.2 Request code

The request codes of the payload of the request frame are shown in Table 5.

[Table 5] Payload request code of request frame

9.4.1.3 Length

The length field is composed of 1 byte, indicates the total length of the request field, and the length field value is variable according to the length and number of request blocks.

9.4.1.4 Request block

The data format of the request block is configured differently according to the request code, and one or more request blocks may be included in the payload of the request frame.

Details of the data format of each request block are as follows.

1) Connection request

The block format of ARq is shown in FIG. 20, and is composed of an 8-byte UID mask. This UID mask can be used to implement a binary search algorithm.

2) separation request

The block format of DaRqD is shown in FIG. 21. The first 2 bytes is the node ID of iWPTN-D for DaRq, and the next 1 byte is the slot number used in the response section. If the node ID is 0xFFFF, this indicates that DaRq is transmitted to all iWPTN-Ds of the group ID.

3) Request connection status

The block format of ASRq is shown in FIG. 22. The first 2 bytes is the iWPTN-D's node ID for ASRq. If the node ID is 0xFFFF, it indicates that ASRq is requested to all iWPTN-Ds of the group ID.

4) Data request

The block format of DRq is shown in FIG. 23. The first 2 bytes are the node ID, the next 1 byte is the slot number, and the last L bytes are the received data type. The data type depends on the application product. For WPT, one of the data types is iWPTN-D charging information, such as remaining battery power, received power level, desired power level, and battery charging.

5) Group ID setup request

The block format of GSRq is shown in FIG. 24. The first 2 bytes are the node ID, the next 1 byte is the slot number, and the last byte is the group ID to be set up.

6) Power transmission request

The block format of PTRq is shown in FIG. 25. The first 2 bytes are the iWPTN-D's node ID for the PTRq. If the node ID is 0xFFFF, it indicates that PTRq is requested for all iWPTN-Ds of the group ID. The next 1 byte is the slot number. The next 1 bit is a request for the remaining power of the battery, the next 1 bit is a request for the power consumption rate, and the next 1 bit is a request for the received power level. 5 bits are reserved for future use, and the last L bytes are data related to iWPTN power reception scheduling.

7) Request to start power transmission

The block format of the PTS is shown in FIG. 26. The first 1 byte is the WPT ID of iWPTN-D for the PTS. If the node ID is 0xFF, PTS is requested for all iWPTN-Ds. The next 1 byte is the slot number, and the last L byte is data related to iWPTN power reception scheduling.

9.4.2 Response frame

The payload format of the response frame has response information to the request of iWPTN-B. The response frame payload is shown in Figure 27. The first byte is the group ID, the second byte is the response code, the third byte is the response data length (L), and the next L bytes is the response data.

9.4.2.1 Group ID

The group address field consists of 1 byte and is used to send RR packets to a specific group. The details of group ID are 6.4.3. See section.

9.4.2.2 Response code

The response code types are shown in Table 6.

[Table 6] Response code of response frame payload

9.4.2.3 Length

The length field consists of 1 byte and indicates the length of the response data; It is variable depending on the response data.

9.4.2.4 Response data

Response data is divided into ARs, DaRs, ASRs, DRs, GSRs and PTRs. The response data format is as follows.

1) Connection response

The block format of ARs is shown in FIG. 28. ARs data consists of 8-byte UIDs.

2) Separation response

The block format of DaRs is shown in FIG. 29. DaRs data consists of 8-byte UIDs.

3) Connection status response

Association status response

The block format of ASRs is shown in FIG. 30. The ASRs data consists of an 8-byte UID and a 1-byte status value.

The status values are shown in Table 7 below.

[Table 7] Association status check value

4) Data response

The block format of DRs is as shown in FIG. 31. The DRs data consists of L bytes of requested data. For WPT according to the requested data type, the data is charging information of iWPTN-D, such as the remaining battery level, the received power level, the desired power level, and the battery discharge rate.

5) Group ID setup response

The block format of GSRs is as shown in FIG. The GSRs data consists of an 8-byte UID with a changed group ID and a 1-byte changed group ID.

6) Power transmission response

The block format of PTRs is as shown in FIG. 33. The PTRs data are 2 bytes for the remaining battery power, 2 bytes for the received power level, and L bytes reserved for future use.

9.4.3 Data frame

The data frame payload contains data to be transmitted. The data frame payload is composed of 8 bytes of UID and L bytes of data as shown in FIG.

9.4.4 Confirmation frame

The acknowledgment frame payload has data for the received response packet. The RA payload format is shown in Figure 35. The first byte is the group ID, the second byte is the response confirmation code, the third byte is the length (L), and the next L byte is the response confirmation block.

9.4.4.1 Group ID

The group ID field is composed of 1 byte and is used to send RR packets to a specific group. For details of the group ID, see Section 6.4.3.

9.4.4.2 Response confirmation code

The response confirmation code types are shown in Table 8.

[Table 8] Response confirmation code

9.4.4.3 Length

The length field consists of 1 byte; This represents the length of the response confirmation data and is variable according to the response confirmation data.

9.4.4.4 Response confirmation block

The response check block is divided into ARs check, DaRs check, ASRs check, DRs check and GSRs check. The block format of acknowledgment is as follows.

1) Check the connection response

The block format of ARs verification is shown in FIG. 36. The first 8 bytes are the UID, and the next 2 bytes are the assigned node ID. The assigned node ID is 0xFFFE, which is the address of a node that is not joined (un-joined), which means that ARq is rejected.

2) Confirmation of separation response

The block format of DaRs verification is shown in FIG. 37. The first 8 bytes are the UID, and the next 2 bytes are the node ID. The assigned node ID is used when separation is not permitted, and if separation is permitted, 0xFFFE, which is a node ID that has not joined, is recorded.

3) Check the connection status response

The block format of ASRs verification is shown in FIG. 38. The ASRs confirmation block consists of 8-byte UIDs.

4) Check data response

The block format of DRs verification is shown in FIG. 39. The first 2 bytes are the node ID, and the next 1 byte is reserved.

5) Check the group ID setup response

The block format of GSRs verification is shown in FIG. 40. The GSRs confirmation block consists of an 8-byte UID and a 1-byte status check value.

Group ID setup status values are shown in Table 9.

[Table 9] Group ID set-up status value

9.5 PSFI frame format

When iWPTN-B provides WPT, there is PSFI in the response section. The PSFI starts when each time slot for WPT for a specific iWPTN-D or group ends, and remains until iWPTN-B receives all PSF frames from the required iWPTN-D. The PSFI frame format has a short and simple structure to sufficiently secure WPT time.

9.5.1 PS Beacon Format

When PSFI is started, iWPTN-B sends a PS beacon for rapid power status update and abnormal situation. The request frame format is shown in FIG. 42.

9.5.1.1 Slot number

This represents the current time slot number and is 1 byte.

9.5.1.2 Frame control

Frame control consists of frame type and PSF policy. The 4 bits are reserved for future use. The format is shown in Figure 43.

1) Frame type

The frame type field is composed of 3 bits. The frame type is defined as two types: a request frame and a response frame.

[Table 10] Frame type value

2) PSF policy

The PSF policy field is composed of 2 bits. PSF policy is defined as two types: response frame transmission policy and no transmission policy.

[Table 11] PSF policy value

3) On-going policy

The policy in progress consists of 1 bit. If the value is 1, WPT is provided in the next time slot, otherwise WPT is stopped.

9.5.1.3 WPT ID number

This represents the number of WPT IDs listed in the frame body.

9.5.1.4 WPT ID

iWPTN-B selects a specific iWPTN-D or group for the response of the PS beacon. In PS beacons, WPT ID is used to shorten the beacon length and simplify the beacon structure. For details of WPT ID, see Section 6.4.5.

9.5.1.5 Frame check sequence

FCS is 8 bits long and is used to confirm that the frame body has been received without error. It is generated using the following 8th order standard generator polynomial.

9.5.2 PSF frame format

After receiving the PSF request in the PS beacon from iWPTN-B, the selected iWPTN-D sends a PSF frame as a response to iWPTN-B. The PSF frame format is shown in Figure 44.

9.5.2.1 Slot number

This represents the current time slot number and is 1 byte.

9.5.2.2 Frame control

The frame control field is composed of a frame type. 5 bits are reserved for future use. The format is shown in Figure 45.

1) Frame type

The frame type field is composed of 3 bits. The frame type is defined as two types: a request frame and a response frame.

[Table 12] Frame type value

9.5.2.3 WPT ID

See Section 6.4.5.

9.5.2.4 Battery level

When iWPTN-B requests battery information, iWPTN-D sends the battery level information. 8 bits are reserved for battery information.

9.5.2.5 Frame check sequence

FCS is 8 bits long and is used to confirm that the frame body has been received without error. It is generated using the following 8th order standard generator polynomial.

9.6 WPT battery discharge frame format

When iWPTN-D discharges the battery, iWPTN-D requests WPT from iWPTN-B in the autonomous section without requesting iWPTN-B. The frame format during battery discharge is the shortest and simplest due to the battery condition.

9.6.1 BPTRq frame format

When the autonomous section starts, the battery discharge iWPTN-D sends a BPTRq ㅍframe for the WPT request. A frame consists of only 1 byte of [00000000]. The BPTRs frame format is shown in Figure 46.

9.6.2 BPTRs frame format

After receiving the BPTRq frame from iWPTN-D, iWPTN-B transmits the BPTRs frame to inform the length of the WPT section in the autonomous section. The BPTRs frame format is shown in Figure 47.

10 MAC layer functions

10.1 General

In order to manage iWPTN, the connection, separation and ASC process for iWPTN-D in the MAC layer of iWPTN are considered. Data may be transmitted in a response period or an autonomous period. In addition, a group ID setup function is provided to manage the iWPTN-D group.

10.2 Network Connection and Disconnection

iWPTN-D must first be connected to iWPTN to communicate with iWPTN-B. Each iWPTN-D searches for a preset iWPTN and connects it to the found iWPTN. If iWPTN is not found, any iWPTN-D can be made iWPTN-B by the user of the application. (In other words, the setting of the new iWPTN is that the new iWPTN-B periodically sends a request packet). However, after the iWPTN is set, the node can maintain the state as iWPTN-B or iWPTN-D depending on the role. In this case, since there is only one channel available, the network setting is canceled if an iWPTN has already been set.

10.2.1 Connection

In the request section, iWPTN-B sends an ARq packet to iWPTN-D without joining. iWPTN-D transmits ARs packets to iWPTN-B in the response section. When iWPTN-B determines whether iWPTN-D is connected to iWPTN, the result is notified through an ARA packet. If the connection is permitted, the assigned node ID is included in the ARA packet, and if the connection is rejected, the non-joined node ID 0xFFFE is recorded. If WiWPTN-D fails to receive ARA packet due to ARA packet error, or PTN-B fails to receive ARs packet, ARq packets are sent to every superframe until all selected iWPTN-D receive ARA packets without error. Send continuously. The connection process to iWPTN-D is completed when iWPTN-D receives an ARA packet from iWPTN-B.

The connection process is shown in Figure 48.

10.2.2 Separation

When iWPTN-B sends a DaRq packet in the request section to iWPTN-D connected to iWPTN, iWPTN-D sends a DaRs packet to iWPTN-B in the response section. iWPTN-B determines whether to separate iWPTN-D from iWPTN, and notifies the result through DaRA packet. If separation is permitted, the node ID of the DaRA packet is recorded as the non-joined node ID 0xFFFE, and if separation is rejected, the assigned node ID is recorded. If the iWPTN-D cannot receive the DaRA packet due to a DaRA packet error or the iWPTN-B cannot receive the DaRs packet, iWPTN-D continuously retransmits the DaRs packet in every superframe until it receives the DaRA packet. Separation is complete when iWPTN-D receives a DaRA packet from iWPTN-B.

The separation procedure is shown in Figure 49.

10.2.3 Check connection status

When iWPTN-B sends an ASRq packet to iWPTN-D connected to the request section, iWPTN-D sends an ASRs packet to iWPTN-B in the response section. iWPTN-B Check the connection status of iWPTN-D to iWPTN and send an ASRA packet. If iWPTN-D fails to receive ASRA packet due to packet error or iWPTN-B fails to receive ASRs packet, iWPTN-D continuously transmits ASRs packet in every time slot until it receives ASRA packet. Checking the connection status of iWPTN-D is completed when iWPTN-D receives an ASRA packet from iWPTN-B.

The procedure for checking the connection status is shown in FIG. 50.

10.3 Data Transfer

In iWPTN, data may be transmitted in a response period or an autonomous period. Data is transmitted in the response section at the request of iWPTN-B or in the autonomous section without request of iWPTN-B.

10.3.1 Transmission in response section

When iWPTN-B transmits a DRq packet to the iWPTN-D connected to the iWPTN in the request period, iWPTN-D transmits a DRs packet in the response period. iWPTN-B receives a DRs packet from iWPTN-D, and then sends a DRA packet. If iWPTN-D cannot receive a DRA packet due to a packet error or iWPTN-B cannot receive a DRs packet, iWPTN-D continuously transmits DRs packets in every time slot until it receives a DRA packet.

The data transmission procedure in the response period is completed when the iWPTN-D receives the DRA packet from iWPTN-B.

The data transmission procedure in the response section is shown in FIG. 51.

10.3.2 Transmission in autonomous section

The autonomous period starts if the iWPTN-D does not transmit a response packet during the timeout period, and becomes this period. It remains until iWPTN-B sends the RR packet. iWPTN-D can transmit data even if there is no request from iWPTN-B during autonomous period. When a system interruption occurs, iWPTN-D can transmit data without requesting iWPTN-B. If the iWPTN-D cannot receive a DA packet due to a packet error or if the iWPTN-B cannot receive a data packet, iWPTN-D continues to transmit the data packet until it receives the DA packet. The data transmission procedure in the autonomous section is completed when the iWPTN-D receives the DA packet from the iWPTN-B.

The data transmission procedure in the autonomous section is shown in FIG. 52.

10.4 Group ID Setup

When iWPTN-B sends a GSRq packet to iWPTN-D in the request section, iWPTN-D sends a GSRs packet in the response section. iWPTN-B checks the group ID setup status of iWPTN-D and sends a GSRA packet.

The group ID setup procedure is shown in FIG. 53.

10.5 Wireless Power Transmission

When iWPTN-B sends a PTRq packet to iWPTN-D, iWPTN-D sends a PTRs packet to iWPTN-B. iWPTN-B performs WPT scheduling with received data in PTRs packet. iWPTN-B broadcasts the PTS packet with the calculated scheduling information to the desired iWPTN-D. When iWPTN-D receives the PTS packet, it follows the scheduling sequence. iWPTN-B provides WPT to iWPTN-D scheduled in the first order. During WPT, another iWPTN-D goes into a power off state to increase power transmission efficiency. When power reception of the first iWPTN-D is finished, iWPTN-B creates a PS beacon in PSFI and transmits it to all iWPTN-Ds. When the PSFI is started, another iWPTN-D is activated to receive the PS beacon. When iWPTN-D receives the PS beacon, iWPTN-D selected by iWPTN-B generates a PSF packet and sends it to iWPTN-B. After confirming the PSF packet from the selected iWPTN-D, iWPTN-B starts WPT for the second iWPTN-D. If the iWPTN-B detects an error during the WPT, the WPT is stopped, and the iWPTN-D recognizes the WPT interruption and then becomes active. When PSFI is started, iWPTN-B sends a PS beacon to notify other iWPTN-Ds of the error detection. This process is repeated until all desired iWPTN-Ds receive power, and iWPTN-B receives PSF packets from iWPTN-D in the last time slot of the response period.

The wireless power transfer procedure is shown in FIG. 54.

10.6 Battery discharge

If iWPTN-D is a battery discharge, WPT is received from iWPTN-B even if the considered node is not known. The battery discharge, iWPTN-D, divides a small portion of the power to be delivered by iWPTN-B to the original destination iWPTN-D. When the current time slot ends, iWPTN-B transmits a PS beacon. The original destination, iWPTN-D, sends a PSF packet in response to the PS beacon and goes to sleep. On the other hand, iWPTN-D, which is a battery discharge, has low battery power, so it remains in a power saving state even after receiving the PS beacon. When the autonomous section starts, the emergency iWPTN-D enters a power saving packet generation state and transmits a BPTRq packet. When iWPTN-B receives a packet, it sends a BPTRs packet in response and provides WPT as an emergency iWPTN-D.

The procedure of battery discharge is shown in FIG. 55.

11 Air interface

11.1 Frequency

The center frequency (fc) of iWPTN is between 80 kHz and 400 kHz; The maximum tolerance can be 88 kHz, 128 kHz, and 370 kHz at ±20 ppm.

11.2 Signal Waveform

56 shows the envelope waveform, and the envelope parameters are defined in Table 13. The amplitude in Table 13 indicates the amplitude of the envelope. The envelope amplitude varies within 10% of the amplitude from the negative variance Mi to the positive variance Mh. tr and tf represent the amplitude increase time of the amplitude from 10% to 90% and the time of decreasing the envelope of the amplitude from 90% to 10%, respectively. The bit interval (Tbit) varies depending on the data rate, and tr and tf cannot exceed 30% of the Tbit.

[Table 13] BPSK envelope parameters

BPSK modulation is used for transmission between iWPTN-B and iWPTN-D. The transmission signal is BPSK modulated according to the envelope defined in this section, as shown in FIG.

Figure 57 shows the BPSK-modulated signal, Figure 58 shows the ASK-modulated signal.

[Table 14] ASK envelope parameters

11.3 WPT signal waveform

59 shows the WPT signal waveform, and envelope parameters are defined in Table 15. In the case of WPT, a common sine wave is used because it provides high efficiency for power transmission. The amplitude in Table 15 indicates the amplitude of the envelope. The envelope amplitude varies within 10% of the amplitude from the negative variance Mi to the positive variance Mh.

[Table 15] WPT envelope parameters

Although the present invention has been described based on the preferred embodiment, the apparatus and method of the present invention are not necessarily limited to the above-described embodiments, and various modifications or variations can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the appended claims will include such modifications or variations as long as they fall within the spirit of the present invention.

Claims (11)

A base station for managing wireless power transmission to the device, connection and disconnection of devices in the charging and communication area, and transmission and reception time of data and wireless power transmission in the wireless power transmission network; And
A device excluding the base station constituting the wireless power transmission network, including a plurality of nodes that are devices receiving wireless power from the base station,
Wireless power transmission and magnetic field communication are performed using one frequency band having a center frequency between 80 kHz and 400 kHz, and as a temporal component, a request period, a response period, and an autonomous period (spontaneous period) Performs wireless power transmission and magnetic field communication through a superframe composed of,
The base station transmits a power transmission request packet to at least one node during the request period, and receives a power transmission response packet from a node receiving the power transmission request packet during the response period, and during the response period, The wireless power transmission schedule information is transmitted to the node receiving the power transmission response packet, and the wireless power is transmitted to the node in response to the wireless power transmission schedule information during the response period.
The response period includes a power status feedback period for power status update and abnormal situation detection,
When receiving a power state beacon within the power state feedback period during wireless power transmission, the node transmits the power state feedback packet informing of the updated power state in response to the power state beacon to the base station,
When the base station detects an abnormal condition of the power status feedback packet, it notifies the node of the abnormal condition,
The base station transmits wireless power during the response period even when the node in the battery discharge state is not included in the scheduling information when the node in the battery discharge state enters the wireless power transmission network,
During the response period, the node in the battery discharge state receives power greater than or equal to a predetermined value required to perform a basic function of magnetic field communication, stops receiving power, and transmits a power transmission request packet during the autonomous period to additional power When receiving, and receiving power above the threshold, stop receiving power, and wait for the request section to join the wireless power transmission network
Electric vehicle charging station management system using phosphorus PLC. delete According to claim 1,
The base station divides the response section into a plurality of slots to correspond to the number of nodes for wireless power transmission, and allocates the divided plurality of slots to the node, an electric vehicle charging station management system using a PLC. delete delete According to claim 1,
When receiving the response request packet from the base station in the active state, the node analyzes the response request packet and switches to the packet generation state when the destination ID matches the ID of the base station, transmits the response packet to the base station, and waits Electric vehicle charging station management system using PLC to switch to the state. The method of claim 6,
The node switches to the power save state when it receives its response acknowledgment packet in the standby state, when a timeout period ends without a slot number being assigned, or when the slot number is allocated and the N+1th timeout period ends. Electric vehicle charging station management system using PLC. The method of claim 6,
When the node receives the response confirmation packet of another node in the standby state, the slot number is allocated and the timeout period ends, or when the response packet is regenerated and retransmitted to the base station, the node switches to the packet generation state. Electric vehicle charging station management system using. The method of claim 6,
The node is an electric vehicle charging station management system using a PLC that is switched to an active state when a wake-up sequence is detected in a power saving state. The method of claim 6,
When the node receives the power state beacon from the base station in the standby state, the node switches to a packet analysis state, generates a power state feedback packet for power state update, transmits it to the base station, and a time time slot is used for the wireless power. Electric vehicle charging station management system using a PLC that is to switch to a power cut-off state or a power transmission state based on whether or not the section is receiving. The method of claim 6,
When the node does not transmit the response packet to the base station during the timeout period, the autonomous section starts and maintains until the base station transmits a response request packet.

Images