Information technology — Telecommunications and information exchange between systems — Magnetic field area network (MFAN) — Part 2: In-band Control Protocol for Wireless Power Transfer

ISO/IEC 15149-2:2015 Standard establishes a system for an in-band network, from which both wireless power transfer and data transmission are carried out simultaneously at the same frequency band. It provides technical solution for a remote and consistent power supply, along with a stable network. For the purpose of this International Standard, the system is designed based on the principles described in ISO/IEC 15149 (Magnetic Field Area Network). In this way, it is expected to achieve superiority in control of devices, while managing wireless power transfer to multiple devices in request. The focus is on the physical and media access control layer protocol; it will not discuss matters on the upper layer protocols. As together, the PHY and MAC layers have to be able to carry out the following tasks: data transmission, signal control, wireless power transfer. This International Standard is applicable in various situations and environments, but is expected to perform excellently in the following certain use cases: - mobile phones: provide ubiquitous charging environments for portable devices; - home appliances: allow unrestrained placement of appliances with the elimination of wire cables and plugs for power supply. The media access control layer protocol is designed for the following scope: - variable superframe structure for wireless power transfer to multiple devices; - simple and effective network topology for efficient wireless power transfer; - dynamic address assignment for efficient timesharing among multiple devices. The physical layer protocol is designed for the following scope: - one frequency band for both wireless power transfer and magnetic field communication; - simple and robust modulation for low-cost implementation and minimized margin of error; - variable coding and bandwidth for dynamic charging environment.

Technologies de l'information — Téléinformatique — Réseau de zone de champ magnétique (MFAN) — Partie 2: Protocole de contrôle dans la bande pour le transfert de puissance sans fil

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INTERNATIONAL ISO/IEC
STANDARD 15149-2
First edition
2015-05-01
Information technology —
Telecommunications and information
exchange between systems —
Magnetic field area network (MFAN) —
Part 2:
In-band Control Protocol for Wireless
Power Transfer
Technologies de l’information — Téléinformatique — Réseau de zone
de champ magnétique (MFAN) —
Partie 2: Protocole de contrôle dans la bande pour le transfert de
puissance sans fil
Reference number
ISO/IEC 15149-2:2015(E)
ISO/IEC 2015
---------------------- Page: 1 ----------------------
ISO/IEC 15149-2:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2015, Published in Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

the requester.
ISO copyright office
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
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ii © ISO/IEC 2015 – All rights reserved
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ISO/IEC 15149-2:2015(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 Overview ....................................................................................................................................................................................................................... 4

6 Network elements ............................................................................................................................................................................................... 5

6.1 General ........................................................................................................................................................................................................... 5

6.2 Time element ............................................................................................................................................................................................ 5

6.2.1 General...................................................................................................................................................................................... 5

6.2.2 Time element for MPAN ........................................................................................................................................... .. 6

6.3 Physical element .................................................................................................................................................................................... 7

6.3.1 Coordinator .......................................................................................................................................................................... 7

6.3.2 Node ............................................................................................................................................................................................ 7

6.4 Address element .................................................................................................................................................................................... 8

6.4.1 MFAN ID ...................................................................... ............................................................................................................. 8

6.4.2 UID ............................................................................................................................................................................................... 8

6.4.3 Group ID .................................................................................................................................................................................. 8

6.4.4 Node ID ...................................................................... ............................................................................................................... 8

6.4.5 WPT ID ...................................................................................................................................................................................... 8

7 Network status ........................................................................................................................................................................................................ 9

7.1 General ........................................................................................................................................................................................................... 9

7.2 Network status for MPAN .............................................................................................................................................................. 9

7.2.1 Stabilization ......................................................................................................................................................................... 9

7.2.2 Invigoration .......................................................................................................................................................................... 9

7.2.3 Revitalization ...................................................................................................................................................................... 9

7.3 MPAN state ................................................................................................................................................................................................. 9

7.3.1 Coordinator state ..........................................................................................................................................................10

7.3.2 Node state ...........................................................................................................................................................................11

8 Physical layer frame format ...................................................................................................................................................................13

8.1 General ........................................................................................................................................................................................................13

8.2 Preamble ...................................................................................................................................................................................................14

8.3 Header .........................................................................................................................................................................................................14

8.4 Payload ........................................................................................................................................................................................................14

8.5 Frame check sequence ..................................................................................................................................................................14

9 MAC layer frame format .............................................................................................................................................................................14

9.1 General ........................................................................................................................................................................................................14

9.2 Frame format for MPAN ...............................................................................................................................................................14

9.2.1 Frame header ...................................................................................................................................................................15

9.2.2 Frame body ........................................................................................................................................................................15

9.2.3 Frame type .........................................................................................................................................................................15

9.2.4 Payload format ................................................................................................................................................................16

9.3 Frame format for power status feedback ......................................................................................................................25

9.3.1 Frame header ...................................................................................................................................................................25

9.3.2 Frame body ........................................................................................................................................................................26

9.3.3 Frame type .........................................................................................................................................................................26

9.3.4 Payload format ................................................................................................................................................................27

10 MAC layer function ...........................................................................................................................................................................................28

10.1 General ........................................................................................................................................................................................................28

© ISO/IEC 2015 – All rights reserved iii
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ISO/IEC 15149-2:2015(E)

10.2 Stabilization ............................................................................................................................................................................................28

10.3 Invigoration ............................................................................................................................................................................................29

10.4 Revitalization .........................................................................................................................................................................................30

11 Air interface ............................................................................................................................................................................................................31

11.1 Frequency .................................................................................................................................................................................................31

11.2 Signal waveform for WPT ...........................................................................................................................................................31

iv © ISO/IEC 2015 – All rights reserved
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ISO/IEC 15149-2:2015(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that are

members of ISO or IEC participate in the development of International Standards through technical

committees established by the respective organization to deal with particular fields of technical

activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international

organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the

work. In the field of information technology, ISO and IEC have established a joint technical committee,

ISO/IEC JTC 1.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for

the different types of document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject

of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.

Details of any patent rights identified during the development of the document will be in the Introduction

and/or on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT), see the following URL: Foreword — Supplementary information.

The committee responsible for this document is ISO/IEC JTC 1, Information technology, Subcommittee SC

6, Telecommunications and information exchange between systems.

ISO/IEC 15149 consists of the following parts, under the general title Information

technology — Telecommunications and information exchange between systems — Magnetic field area

network (MFAN):
— Part 1: Air interface
— Part 2: In-band control protocol for wireless power transfer
— Part 3: Relay protocol for extended range
— Part 4: Security protocol for authorization
© ISO/IEC 2015 – All rights reserved v
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ISO/IEC 15149-2:2015(E)
Introduction

This International Standard provides protocols for magnetic field area network (MFAN). MFAN can support

the service based on wireless communication and wireless power transfer in harsh environment. MFAN is

composed of four protocols; air interface, in-band control protocol, relay protocol, and security protocol.

ISO/IEC 15149–1 specifies the physical layer and media access control layer protocols of wireless

network over a magnetic field.

ISO/IEC 15149–2 specifies the control protocol for wireless power transfer based on magnetic field

area network.

ISO/IEC 15149–3 specifies the relay protocol to extend effective network coverage of magnetic field

area network.

ISO/IEC 15149–4 specifies the security protocol to authorize nodes to communicate in magnetic field

area network.
vi © ISO/IEC 2015 – All rights reserved
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INTERNATIONAL STANDARD ISO/IEC 15149-2:2015(E)
Information technology — Telecommunications and
information exchange between systems — Magnetic field
area network (MFAN) —
Part 2:
In-band Control Protocol for Wireless Power Transfer
1 Scope

This International Standard establishes a system for an in-band network, from which both wireless

power transfer and data transmission are carried out simultaneously at the same frequency band. It

provides technical solution for a remote and consistent power supply, along with a stable network.

For the purpose of this International Standard, the system is designed based on the principles described

in ISO/IEC 15149 (Magnetic Field Area Network). In this way, it is expected to achieve superiority in

control of devices, while managing wireless power transfer to multiple devices in request. The focus is

on the physical and media access control layer protocol; it will not discuss matters on the upper layer

protocols. As together, the PHY and MAC layers have to be able to carry out the following tasks: data

transmission, signal control, wireless power transfer.

This International Standard is applicable in various situations and environments, but is expected to

perform excellently in the following certain use cases:
— mobile phones: provide ubiquitous charging environments for portable devices;

— home appliances: allow unrestrained placement of appliances with the elimination of wire cables

and plugs for power supply.
The media access control layer protocol is designed for the following scope:
— variable superframe structure for wireless power transfer to multiple devices;
— simple and effective network topology for efficient wireless power transfer;
— dynamic address assignment for efficient timesharing among multiple devices.
The physical layer protocol is designed for the following scope:

— one frequency band for both wireless power transfer and magnetic field communication;

— simple and robust modulation for low-cost implementation and minimized margin of error;

— variable coding and bandwidth for dynamic charging environment.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO/IEC 15149-1:2014, Information technology — Telecommunications and information exchange between

systems — Magnetic field area network (MFAN) — Part 1: Air interface
© ISO/IEC 2015 – All rights reserved 1
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ISO/IEC 15149-2:2015(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
wireless power transfer
WPT

method of consistent and simultaneous power supply to multiple devices within a range without

physical contact
3.2
magnetic field area network
MFAN

wireless network that provides reliable communication in harsh environments using magnetic field

3.3
magnetic power network
MPAN

in-band wireless power transfer network that incorporates magnetic field area network (MFAN) in its

communication and wireless power transfer within a single frequency band
3.4
magnetic power area network–coordinator
MPAN-C

device that carries out integral operations for magnetic power area network; wireless power transfer,

connection and release of devices, and time scheduling of power transfer and data

3.5
magnetic power area network–node
MPAN-N
devices that comprises magnetic power area network and that is not a coordinator
4 Symbols and abbreviated terms
The following acronyms are used in this document:
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
CRC Cyclic Redundancy Check
DA Data Acknowledgement
DaRq Disassociation Request
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ISO/IEC 15149-2:2015(E)
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
LSB Least Significant Bit
MAC Media Access Control
NRZ-L Non-Return-to-Zero Level
PHY Physical Layer Protocol
PLRC Power Level Request Command
PLRCA Power Level Request Command Acknowledgement
PS Power Status
PSF Power Status Feedback
PSFI Power Status Feedback Interval
PT Power Transfer
PTBRq Power Transfer Beacon Request
PTEC Power Transfer Execution Command
PTECA Power Transfer Execution Command Acknowledgement
PTPC Power Transfer Permission Command
PTRC Power Transfer Request Command
PTRq Power Transfer Request
PTRs Power Transfer Response
RA Response Acknowledgement
RR Response Request
SIFS Short Inter Frame Space
TDMA Time Division Multiple Access
UID Unique Identifier
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ISO/IEC 15149-2:2015(E)
5 Overview

MPAN is an in-band wireless network system that enables wireless communication and wireless power

transfer within a single frequency band. Data and control commands are communicated according to the

MFAN system; power is transferred wirelessly according to the consistent WPT system, both at the same

frequency band. Due to the characteristics of magnetic field and legal regulations on the power level, the

range of MFAN is wider than that of WPT. Within the MPAN, the maximum WPT efficiency is achieved

with an MPAN-C taking in charge of every scheduling accordingly for devices in most effective orders.

The MFAN has a low carrier frequency bandwidth of 30 KHz to 300 KHz; the same frequency band is

used for WPT. It uses a simple and robust modulation method like BPSK for low cost implementation

and low error probability. Also dynamic coding methods like Manchester and NRZ-L are considered

in specific against noises. It can provide data transmission speed of several kbps within a distance of

several meters. For WPT, unmodulated sine sinusoidal signal is used to enhance WPT efficiency. The

MPAN uses a simple and efficient network topology like the ‘star topology‘ for low power consumption.

It uses dynamic address assignment for small packet size, so to manage address efficiently as well. Also it

incorporates an adaptive link quality control by using various transmission speeds, and coding methods

suitable for various MPAN environments.

There are two kinds of devices participating in an MPAN according to their functions: MPAN-C and

MPAN-N. Only one MPAN-C may exist within an MPAN, where a number of MPAN-Ns may be registered

to. As a base station of MPAN, MPAN-C manages connection and release of MPAN-Ns when there is

response to its request. For the data transmission, MPAN uses TDMA method; When an MPAN-N joins

MPAN managed by MPAN-C, MPAN-C allocates time-slots for the MPAN-N. WPT and data transmission

would begin as MPAN-C requests for the responses of MPAN-Ns.

As shown in Figure 1, MPAN-C and MPAN-Ns are to be located elsewhere within the network. If MPAN-C

receives relevant data for WPT — ID, battery information, etc. — from MPAN-Ns, it examines factors

like power transfer sequences or the number of time slots for an appropriate WPT. MPAN-C then sends

control data back to MPAN-Ns to manage overall WPT operations.
Figure 1 — Wireless Power Transfer System

MPAN can be applied to various industries. It may be applied to a situation where electric devices are

in need of constant power supply to function properly. For some industries, significant improvement in

efficiency is attainable simply by providing power wirelessly. In any cases, duration of battery life no

longer becomes a problem; no need to spare broad space for spacious batteries and charging equipment.

As for an example, there has always been a battery issue when it comes to using mobile devices

(Figure 2) due to its running time. MPAN is able to provide a ubiquitous charging environment while on

a stable network service. Also for the home appliances (Figure 3), complex wire cables and plugs can be

eliminated; a placement of home appliances at one’s convenience becomes possible with MPAN.

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ISO/IEC 15149-2:2015(E)
Figure 2 — Mobile Devices
Figure 3 — Home Appliances
6 Network elements
6.1 General

The elements of MPAN, based on the elements of MFAN, are classified in two: time and physical element.

The time element refers to the superframe structure consisting of request period, response period, and

spontaneous period. The physical element refers to the MPAN devices: MPAN-C and MPAN-Ns. The most

basic unit in the physical element is device. A device may be defined according to its role either as an

MPAN-C that manages network, or an MPAN-N that communicates with MPAN-C.

When an MPAN is set up, a node is allocated to be an MPAN-C: the device in charge of the perfect control

of association, disassociation, release, and time scheduling for MPAN-Ns. The superframe begins when

a device is set as an MPAN-C, and starts to transmit request packets during the request period. Within

MPAN, only a single channel is permitted by an MPAN-C; the rest devices within the MPAN become

MPAN-Ns. Note that a device within an MPAN may participate as an MPAN-C or MPAN-N depending upon

its role. For the connection between an MPAN-C and an MPAN-N, a peer-to-peer connection is used.

6.2 Time element
6.2.1 General

The MPAN inherits the same time elements used in MFAN, ISO/IEC 15149-1, which is much similar to

the method used in TDMA time slot; MPAN-C arranges times slots for individual MPAN-Ns. MPAN-C

manages data from the group of MPAN-Ns during response period. There are some new features newly

introduced from ISO/IEC 15149-2 in relation to WPT.
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ISO/IEC 15149-2:2015(E)
6.2.2 Time element for MPAN

The time element of MPAN, as shown in Figure 4, consists of request period, response period, and

spontaneous period. The lengths of request and response period are varied; the length of spontaneous

period is subject to the length of request and response period.

The superframe begins when MPAN-C transmits a PTRq packet to MPAN-Ns during the request period.

When MPAN-N receives the packet, it sends PTRs packet back as a response. According to the PTRs

packets received, MPAN-C sends PTBRq packet with information on the WPT time schedule. In that case,

relevant MPAN-Ns can receive WPT during the following response periods. During the power status

feedback interval, MPAN-Ns will transmit the PSF packet as a response to the PS beacon from MPAN-C.

Figure 4 — MPAN superframe structure
6.2.2.1 Request period

During the request period, MPAN-C transmits PTRq packet to invite MPAN-Ns to WPT time schedule.

Receiving PTRq packet, MPAN-Ns prepare to take WPT from MPAN-C.
6.2.2.2 Response period

The response period can be divided into several time slots by the number of MPAN-Ns for WPT. The

length of each time slot varies according to the total length of WPT. When MPAN-C schedules for a

response period, MPAN-C allocates slot numbers to each time slots in a numerical order; if there is not an

MPAN-N, the slot number will be zero. MPAN-C may assign each time slot either to an individual MPAN-N

or to a group of MPAN-Ns. According to a sequence of the schedule, an MPAN-N or all the MPAN-Ns in a

group may receive wireless power simultaneously.

During the response period of MPAN, MPAN-Ns send PTRs to MPAN-C if the node is in need of WPT. The

MPAN-Ns put in schedule by MPAN-C can receive WPT during the response period. MPAN-C, with the

information received, calculates distance to MPAN-Ns. MPAN-C will then return PTBRq to MPAN-Ns to

provide detailed time schedule and start WPT at a power level appropriate for the distance.

Distinguishable to the MFAN response period, the response period of MPAN has PSFI. After each time

slot, there is a PSFI for quick power status update and abnormal situation. During WPT, when MPAN-N

receives the PS beacon in the PSFI, it transmits the PSF packet to MPAN-C for notifying the updated

power status as the response for the PS beacon in the PSFI. When abnormal situation is sensed by the

MPAN-C, it is notified to all MPAN-Ns in the PSFI by the MPAN-C. When the MPAN-Ns recognize error by

receiving the PS beacon, they wait until receiving a request from the MPAN-C.
6 © ISO/IEC 2015 – All rights reserved
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ISO/IEC 15149-2:2015(E)
Figure 5 — PSFI in response period
6.2.2.3 Spontaneous period

The spontaneous period begins when MPAN-C confirms all PSF packets from MPAN-Ns in the last

time slot of the response period and broadcasts PTPC. It will last until MPAN-C will transmit a RR

packet again. During this period, low power devices can request power transfer without MPAN-C’s

request. When MPAN-C receives PTRC packet, it returns PTEC packet. As MPAN-C receives PTECA,

the acknowledgement, it provides WPT to low power devices for a certain length of time. Afterward,

MPAN-C
...

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