ISO/IEC 15149-1:2014

Information technology - Telecommunications and information exchange between systems - Magnetic field area network (MFAN) - Part 1: Air interface

ISO/IEC 15149-1:2014 specifies the physical layer and media access control layer protocols of wireless network over a magnetic field in a low frequency band (~300 kHz) for wireless communication in harsh environment (around metal, underwater, underground, etc.). The physical layer protocol is designed for the following scope: low carrier frequency for large magnetic field area and reliable communication in harsh environment; simple and robust modulation for a low implementation cost and error performance; variable coding and bandwidth for a link adaptation. The media access control layer protocol is designed for the following scope: simple and efficient network topology for low power consumption; variable superframe structure for compact and efficient data transmission; dynamic address assignment for small packet size and efficient address management. ISO/IEC 15149-1:2014 supports several kbps data transmission in wireless network within a distance of several metres. It can be applied to various services such as the following areas: environmental industry to manage pollution levels in soil and water using wireless underground or underwater sensors; construction industry to monitor the integrity of buildings and bridges using wireless, inner-corrosion sensors; consumer-electronics industry to detect food spoilage in wet, airtight storage areas and transfer the sensing data from the inside to the outside; agricultural industry to manage the moisture level as well as mineral status in soil using wireless, buried sensors; transportation industry to manage road conditions and traffic information using wireless, underground sensors.

Technologies de l'information — Téléinformatique — Réseau de zone de champ magnétique (MFAN) — Partie 1: Interface radio

General Information

• Status: Published
• Publication Date: 01-Jul-2014
• ICS: 35.110 - Networking
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6/WG 1 - Physical and data link layers
• Current Stage: 9093 - International Standard confirmed
• Start Date: 23-May-2025
• Completion Date: 30-Oct-2025

Relations

• Revises: ISO/IEC 15149:2011 - Information technology - Telecommunications and information exchange between systems - Magnetic field area network (MFAN)
• Effective Date: 07-Oct-2012

Overview - ISO/IEC 15149-1:2014 (MFAN Air Interface)

ISO/IEC 15149-1:2014 defines the air interface for a Magnetic Field Area Network (MFAN) - a wireless communication standard that uses low-frequency magnetic fields (≈300 kHz) to enable reliable data exchange in harsh environments (around metal, underwater, underground). This part specifies the physical (PHY) layer and media access control (MAC) layer protocols to support several kbps data rates across distances of several metres, emphasizing robustness, low cost, and low power operation.

Key Topics and Technical Requirements

• Physical layer (PHY)

  • Low carrier frequency (~300 kHz) to create a large magnetic field area and penetrate metal/soil/water.
  • Simple, robust modulation schemes (example: BPSK) and noise-robust coding (examples: Manchester, NRZ‑L) to reduce error rates and implementation complexity.
  • Variable coding and bandwidth mechanisms to enable link adaptation and improve reliability.

• Media Access Control (MAC)

  • Simple, energy-efficient network topology (star-like with a single coordinator, MFAN‑C, and multiple nodes, MFAN‑N) to minimize power use.
  • Time Division Multiple Access (TDMA) with coordinator-assigned time slots and a variable superframe structure for compact, efficient data transfer.
  • Dynamic address assignment for small packet sizes and efficient address management; support for association/disassociation, group ID setup, and network state management.

• Network elements & behavior

  • Definitions for coordinator (MFAN‑C) and node (MFAN‑N), network association procedures, frame formats (PHY and MAC), and payload/acknowledgement handling.
  • Intended to operate reliably in harsh physical conditions and support adaptive link quality control.

Practical Applications and Who Uses It

ISO/IEC 15149-1 is designed for systems that require wireless communication where conventional RF performs poorly. Typical use cases:

• Environmental monitoring - buried or underwater sensors for soil/water pollution and parameter tracking.
• Construction and infrastructure - internal corrosion monitoring, building and bridge structural health sensors.
• Agriculture - buried sensors for soil moisture and mineral status management.
• Transportation and utilities - underground sensors for road/traffic condition and pipeline leak detection.
• Consumer electronics - sensing inside wet or airtight storage (e.g., food spoilage detection).

Primary users and stakeholders:

• Embedded system designers and firmware engineers building MFAN nodes and coordinators.
• Sensor network integrators for harsh-environment deployments.
• Industrial IoT architects, utility and infrastructure monitoring teams, and standards/quality engineers evaluating low-frequency magnetic communication solutions.

Related Standards

• ISO/IEC 15149-2 - In-band Control Protocol for Wireless Power Transfer (companion control protocol).
• Future parts planned: Relay protocol (extended range) and Security/Authorization protocol (Parts 3 and 4).

Keywords: ISO/IEC 15149-1, MFAN, magnetic field area network, air interface, low frequency (~300 kHz), physical layer, MAC layer, BPSK, TDMA, underground sensors, underwater communication, harsh environment.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 15149-1
First edition
2014-07-01
Information technology —
Telecommunications and information
exchange between systems —
Magnetic field area network (MFAN) —
Part 1:
Air interface
Technologies de l’information — Téléinformatique — Réseau de zone
de champ magnétique (MFAN) —
Partie 1: Interface radio
Reference number
©
ISO/IEC 2014
© ISO/IEC 2014
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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2014 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
3 Symbols and abbreviated terms . 2
4 Overview . 3
5 Network elements . 5
5.1 General . 5
5.2 Time element . 6
5.3 Physical element . 7
5.4 Address element . 8
6 Network status . 9
6.1 General . 9
6.2 Network configuration . 9
6.3 Network association . 9
6.4 Network disassociation . 9
6.5 Data transmission. 9
6.6 Network release .10
6.7 MFAN device state .10
7 PHY layer.12
7.1 PHY layer frame format .12
7.2 Coding and modulation .14
8 MAC layer frame format .18
8.1 General .18
8.2 Frame format .18
8.3 Frame type .20
8.4 Payload format .22
9 MAC layer function .30
9.1 General .30
9.2 Network association and disassociation .30
9.3 Data transmission.32
9.4 Group ID set-up .33
10 Air interface .33
10.1 Frequency .33
10.2 Signal waveform . .33
Bibliography .36
© ISO/IEC 2014 – All rights reserved iii

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, Subcommittee SC 6, Telecommunications
and information exchange between systems.
This first edition of ISO/IEC 15149-1 cancels and replaces ISO/IEC 15149:2011, of which it constitutes a
minor revision.
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
Relay Protocol for Extended Range and Security Protocol for Authorization will form the subjects of future
Parts 3 and 4, respectively.
iv © ISO/IEC 2014 – All rights reserved

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.
This part of ISO/IEC 15149 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 secuity protocol to authorize nodes to communicate in magnetic field
area network.
© ISO/IEC 2014 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 15149-1:2014(E)
Information technology — Telecommunications and
information exchange between systems — Magnetic field
area network (MFAN) —
Part 1:
Air interface
1 Scope
This part of ISO/IEC 15149 specifies the physical layer and media access control layer protocols of
wireless network over a magnetic field in a low frequency band (~300 KHz) for wireless communication
in harsh environment (i.e., around metal, underwater, underground, etc.).
The physical layer protocol is designed for the following scope:
— low carrier frequency for large magnetic field area and reliable communication in harsh environment;
— simple and robust modulation for a low implementation cost and error performance;
— variable coding and bandwidth for a link adaptation.
The media access control layer protocol is designed for the following scope:
— simple and efficient network topology for low power consumption;
— variable superframe structure for compact and efficient data transmission;
— dynamic address assignment for small packet size and efficient address management.
This part of ISO/IEC 15149 supports several Kbps data transmission in wireless network within a
distance of several meters. It can be applied to various services such as the following areas:
— environmental industry to manage pollution levels in soil and water using wireless underground or
underwater sensors;
— construction industry to monitor the integrity of buildings and bridges using wireless, inner-
corrosion sensors;
— consumer-electronics industry to detect food spoilage in wet, airtight storage areas and transfer
the sensing data from the inside to the outside;
— agricultural industry to manage the moisture level as well as mineral status in soil using wireless,
buried sensors;
— transportation industry to manage road conditions and traffic information using wireless,
underground sensors.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
© ISO/IEC 2014 – All rights reserved 1

2.1
magnetic field area network
MFAN
wireless network that provides reliable communication in harsh environments using magnetic field
2.2
magnetic field area network coordinator
MFAN-C
device that manages the connection and release of nodes within the communication area and the sending
and receiving time of data in an MFAN
2.3
magnetic field area network node
MFAN-N
device, except the coordinator, that forms a network in an MFAN
3 Symbols and abbreviated terms
The following acronyms are used in this part of ISO/IEC 15149:
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
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
2 © ISO/IEC 2014 – All rights reserved

GSRA group ID set-up response acknowledgement
HCS header check sequence
LSB least significant bit
MAC media access control
MFAN magnetic field area network
MFAN-C magnetic field area network coordinator
MFAN-N magnetic field area network node
NRZ-L non-return-to-zero level
PHY physical layer protocol
RA response acknowledgement
RR response request
SIFS short interframe space
TDMA time division multiple access
UID unique identifier
4 Overview
MFAN is a wireless communication network that can transmit and receive data over a magnetic field in
a low frequency band. Wireless communication over a magnetic field enables reliable communication
and extends the communication system coverage around metal, soil, and water. It is designed using
those characteristics of the magnetic field communication. It uses a low carrier frequency for reliable
communication and large magnetic field area in harsh environments, a simple and robust modulation
like BPSK for a low implementation cost and error probability, and a dynamic coding technique like
Manchester or NRZ-L coding for noise robustness. In essence, it provides several kbps data transmission
within a distance of several meters.
Also, it uses a simple and efficient network topology like a star topology for low power consumption.
The dynamic address assignment is used for the small packet size and efficient address management,
and the adaptive link quality control is considered with variable data transmission speed and coding.
The devices in MFAN are specified into two elements according to the role: MFAN-C for a coordinator,
and MFAN-N for a node. In a network, there can be one coordinator. When a node joins the network,
the coordinator assigns the time-slots for each device upon the node’s request and the coordinator’s
decision. So, TDMA is considered for the data transmission.
As shown in Figure 1, MFAN-Ns are buried under the ground, and MFAN-C is placed above the ground.
If MFAN-N receives the sensing data from the sensors, MFAN-N sends its received data to MFAN-C over
a magnetic field. MFAN-C sends the received data from MFAN-N to the monitoring center by either
wireless or wired communication for long distance.
© ISO/IEC 2014 – All rights reserved 3

Figure 1 — Underground monitoring system
Wireless communication in harsh environment has been significantly required in various industries. It
is difficult for a sensor node to transmit its data by a radio frequency around metal, soil, and water with
the existing standards of wireless communication. MFAN is an alternative standard that enables several
sensor nodes inside metal, soil, and water to transfer their data to a coordinator outside using the
characteristics of magnetic field. Therefore it can be applied to various services in harsh environment.
For example, in ground status monitoring as shown in Figure 2, the sensor nodes can be buried under
the ground to sense ground cave-in, ground sinking, land sliding, and so on. Another example of MFAN is
the underground infrastructure management in Figure 3. In this example, the sensor nodes are attached
to the pipes, and can detect gas or water leaks and notify its location. For the building and bridge
management in Figure 4, the sensor nodes can be placed on beams and columns to detect the integrity
of the structure. In pollution monitoring as shown in Figure 5, the sensor nodes can detect the quality
of the soil and water. It can detect poisonous chemical, pH(Hydrogen ion exponent), and temperature by
sensor nodes that are placed below ground and water.
Figure 2 — Ground status monitoring
4 © ISO/IEC 2014 – All rights reserved

Figure 3 — Underground infrastructure management
Figure 4 — Building & bridge management
Figure 5 — Pollution monitoring
5 Network elements
5.1 General
The main elements of MFAN are divided into time and physical element. The time element refers to
the superframe consisting of a request period, a response period, and a spontaneous period, and the
physical element refers to the network consisting of MFAN-C and MFAN-Ns. The most basic one in the
physical element is the node. Node is classified into two types: MFAN-C to manage the network and
MFAN-N to communicate with MFAN-C.
Figure 6-7 show the structures of superframe and network which are the time and physical elements,
respectively. The node that needs to be decided first in MFAN is MFAN-C, and the superframe begins
with MFAN-C transmitting a request packet in the request period. MFAN-C is charged of managing the
association, disassociation, release, and scheduling of MFAN-Ns. One MFAN can use one channel where
only one node is utilized as MFAN-C and the rest of them become MFAN-N. The rest of the nodes in
© ISO/IEC 2014 – All rights reserved 5

MFAN excluding MFAN-C become MFAN-N. Note that any nodes can become either MFAN-C or MFAN-N
depending upon its role. Basically, a peer-to-peer connection between MFAN-C and MFAN-N is considered.
5.2 Time element
The time element used in MFAN is the time slot of the TDMA method. MFAN-C manages the MFAN-N
group that transmits data in the response period, and the time slots are self-arranged by the selected
MFAN-Ns. The superframe of MFAN, as shown in Figure 6, consists of a request period, a response
period, and a spontaneous period, and the lengths of the request and response period are variable. The
superframe begins with MFAN-C transmitting a RR packet to MFAN-Ns in the request period.
The RR packet has information which MFAN-Ns can send response packets during response periods,
and the selected MFAN-Ns can transmit the response packet in the response period according to the RR
packet information.
Figure 6 — MFAN superframe structure
5.2.1 Request period
In the request period, MFAN-C transmits the RR packet with the information about the usage of MFAN-
Ns in order for MFAN-N to send the response packet during response periods.
5.2.2 Response period
In the response period, MFAN-N can transmit response packet according to the received RR packet of
MFAN-C, and the response period can be divided into several time slots according to the number of the
selected MFAN-Ns in MFAN. Each time slot length is variable according to the length of the response
frame and the acknowledgement. If the MFAN-C schedules a response period, the slot number is decided
by the order of the divided time slot. Otherwise the slot number is zero. MFAN-C assigns time slots to
either MFAN-N or a particular group for the use of the response period, and the nodes in the assigned
group independently transmit the data frame in the response period.
6 © ISO/IEC 2014 – All rights reserved

5.2.3 Spontaneous period
The spontaneous period begins when there is no node transmitting the response packet for a certain
period of time. In this period, nodes can transmit data even without MFAN-C’s request. This period is
maintained until MFAN-C transmits a request packet.
5.2.4 Network activation
The superframe of MFAN is divided into the request period, the response period, and the spontaneous
period. MFAN-C and MFAN-Ns in MFAN operate in each period as follows:
5.2.4.1 Request packet transmission within the request period
In the request period, MFAN-C sends the RR packet to MFAN-Ns. Based on this, the MFAN-N that have
received the RR packet decide whether to transmit response packets in the response period. MFAN-C
can determine the MFAN-N group to transmit in the response period.
5.2.4.2 Response packet transmission within the response period
The MFAN-Ns selected by MFAN-C can transmit the response packet in the response period. When
MFAN-N transmits the response packet in the response period, MFAN-C that has received the response
packet transmits the RA packet. MFAN-N that has not received the RA packet transmits response packets
every time-slot until it receives a RA packet from MFAN-C.
5.2.4.3 Data packet transmission in the spontaneous period
A spontaneous period begins if MFAN-N does not transmit any response packets for a certain period
of time, and this period is maintained until MFAN-C transmits a RR packet. In the spontaneous period,
MFAN-N can transmit data without the request of MFAN-C.
5.3 Physical element
The physical element configuring MFAN is divided into MFAN-C and MFAN-N in which all MFAN-Ns are
connected into MFAN-C (i.e. a central connectivity device). The basic element, node, is distinguished
into MFAN-C and MFAN-N according to its role. MFAN-C manages the whole MFAN and there must exist
only one MFAN-C per one network. MFAN-C manages MFAN-N by sending the RR packet. MFAN-N must
transmit response packets according to MFAN-C’s management. MFAN can be configured as shown in
Figure 7.
5.3.1 MFAN-C
MFAN-C is a node that manages MFAN; only one MFAN-C exists per one network, and it manages and
controls MFAN-N by the RR packet.
5.3.2 MFAN-N
MFAN-N is a node that resides within an MFAN (excluding MFAN-C), and a maximum of 65,519 MFAN-Ns
can exist per network. It transmits response packets according to the RR packet transmitted by MFAN-C.
© ISO/IEC 2014 – All rights reserved 7

Figure 7 — MFAN
5.4 Address element
In order to identify MFAN-Ns, MFAN uses address systems such as MFAN ID, UID, group ID and node ID.
5.4.1 MFAN ID
MFAN has its own ID that identifies each network from the others; the value should not be duplicated
in other MFANs, and the value is maintained as long as MFAN exists. Its value is defined by user to
distinguish networks.
5.4.2 UID
UID is a unique identifier consisting of 64 bits; it consists of group ID, IC manufacturer’s code, and IC
manufacturer’s serial number. MFAN-N is identified by UID.
Unit: Byte
Figure 8 — UID structure
5.4.3 Group ID
MFAN-N can be grouped by applications. Group ID is the identifier for the grouped MFAN-Ns within the
network. MFAN-C can request a response to a specific MFAN-N group in order to mitigate the packet
collision. Some group IDs are reserved in Table 1. Its value is defined by user to distinguish groups.
8 © ISO/IEC 2014 – All rights reserved

Table 1 — Reserved group ID
Group ID Content Remarks
0xFF All groups When selecting all groups
0xF0 – 0xFE Reserved —
5.4.4 Node ID
Node ID is an identifier used instead of UID to identify nodes, and it has a 16 bit address assigned by
MFAN-C. Some node IDs are reserved in Table 2.
Table 2 — Reserved node ID
Node ID Content Remarks
0xFFFF All nodes When broadcasting or transmitting all nodes
0xFFFE Unjoined node Default ID for MFAN-N
0xFFF0 – 0xFFFD Reserved —
6 Network status
6.1 General
In an MFAN, MFAN-N may enter the active states of network configuration, network association,
response transmission, data transmission, network disassociation, and network release.
6.2 Network configuration
MFAN-C configures a network by transmitting a request packet to MFAN-N in the request period. MFAN
ID is included in the request packet so that MFAN-N can identify the connecting network. The minimum
period of network means when only MFAN-C exists, and it consists of only the request period and the
spontaneous period.
6.3 Network association
When MFAN-C sends the ARq packet in the request period, MFAN-N probes the received packet and
then if it is the ARq packet for the desired MFAN, MFAN-N sends the ARs packet to the MFAN-C in the
response period. MFAN-C, having received the ARs packet, transmits the ARA packet to MFAN-N. The
network association of MFAN-N is completed upon receiving the ARA packet from MFAN-C.
6.4 Network disassociation
MFAN-N, associated with MFAN, can be disassociated either by MFAN-C’s request or by itself. MFAN-C
can send the DaRq packet to MFAN-N according to the current network status for a forced disassociation.
In the case of spontaneous disassociation due to shutting down and going out of the network coverage,
MFAN-C can know the association status of MFAN-N by the response of ASRq from MFAN-C.
6.5 Data transmission
When MFAN-C sends the DRq packet in the request period to MFAN-N, MFAN-N sends DRs packet to
MFAN-C according to the requested data type. Upon receiving the DRs packet, MFAN-C sends the DRA
packet to MFAN-N, and MFAN-N, having received the DRA packet, completes the data transmission.
© ISO/IEC 2014 – All rights reserved 9

6.6 Network release
MFAN release can be divided into normal release through the request of MFAN-Ns and abnormal release
due to a sudden situation. Normal release refers to MFAN-C releasing the network by its own decision
and by sending the DaRq packet to all MFAN-Ns. Abnormal network release refers to MFAN-C shutting
down or going out of the network coverage.
6.7 MFAN device state
MFAN device state includes the MFAN-C state and the MFAN-N state. In detail, MFAN-C states are divided
into the standby state, the packet analysis state, and the packet generation state whereas MFAN-N states
are composed of the hibernation state, the activation state, the standby state, the packet analysis state,
and the packet generation state.
6.7.1 MFAN-C state
The state of MFAN-C goes to the standby state when the power turns on. In the standby state, when the
application system commands sending the RR packet or the superframe begins, the state of MFAN-C
goes to the packet generation state and MFAN-C sends the RR packet to MFAN-Ns. And then the state of
MFAN-C goes back to the standby state. If MFAN-C receives the packet (either response or data packet)
from MFAN-Ns while doing the carrier detection in the standby state, the state of MFAN-C goes to the
packet analysis state. If the destination ID of the received packet and the node ID of MFAN-C are the same,
the state of MFAN-C goes to the packet generation state, and then MFAN-C generates the RA or DA packet
and sends it to MFAN-N in the packet generation state. After that, the state of MFAN-C goes back to the
standby state. On the other hand, if there are errors in the data packet, the state of MFAN-C goes back
directly to the standby state. In the packet analysis state, when there are errors in the received response
packet or destination ID of the received response packet and node ID of MFAN-C do not correspond,
MFAN-C regenerates the RR packet in the packet generation state and retransmits it to MFAN-Ns, and
then the state goes to the standby state. If these failures occur consecutively, the procedure of the packet
analysis state is repeated as many times as needed (maximum N times). In (N+1)th procedure, the state
of MFAN-C goes from the packet analysis state to the standby state. MFAN-C state diagram is as Figure 9.
Figure 9 — MFAN-C state diagram
10 © ISO/IEC 2014 – All rights reserved

6.7.2 MFAN-N state
The state of MFAN-N goes into the hibernation state when the power turns on. In the hibernation state,
when the wake-up sequence is detected, the state goes into the activation state. The wake-up sequence
is defined in 7.1. When MFAN-N receives the RR packet, the state of MFAN-N goes into the packet analysis
state and MFAN-N analyzes the received RR packet. If the destination ID of the RR packet and MFAN-N
ID (group ID and node ID) correspond, the state of MFAN-N goes into the packet generation state and
MFAN-N sends the response packet to MFAN-C, and then the state of MFAN-N moves into the standby
state. If not, the state goes back to the hibernation state.
While doing the carrier detection in the standby state, the state of MFAN-N goes to the hibernation
state when MFAN-N receives the RA packet of its own node or to the packet generation state when
MFNA-N receives the RA packet of other nodes. And the state of MFAN-N goes to the hibernation state
when the slot-number is not allocated and the time-out period is over in the standby state or to the
packet generation state when the slot-number is allocated and the time-out period is over (up to N
times consecutively). However, the state goes to the hibernation state when the slot-number is allocated
and the time-out period at N+1th is over. If the slot-number is allocated and MFAN-N does not receive
RA packet during the time-out period, the state of MFAN-N goes from the standby state to the packet
generation state. And then MFAN-N regenerates and retransmits the response packet to MFAN-C and
the state of MFAN-N goes from the packet generation state to the standby state. The retransmission of
the response packet is repeated as many times as needed (maximum N times). In the (N+1)th time-out
period, the state goes from the standby state to the hibernation state. If MFAN-N receives the RR packet
in the standby state while doing the carrier detection, the state is moved to the packet analysis state.
When the system interrupt occurs in the hibernation state, the state of MFAN-N is changed to the
activation state. If MFAN-N receives data from the system, the state goes to the packet generation state.
And then MFNA-N generates and sends data packet to the MFAN-C, and the state of MFAN-N goes to the
standby state. If MFAN-N receives the DA packet, the state goes back to the hibernation state. If not, the
state goes to the packet generation state and MFAN-N retransmits the data and then the state goes back
to the standby state up to N times. MFAN-N state diagram is as Figure 10.
Figure 10 — MFAN-N state diagram
© ISO/IEC 2014 – All rights reserved 11

7 PHY layer
7.1 PHY layer frame format
7.1.1 General
This section describes the physical layer frame format. As shown in Figure 11, the PHY layer frame
consists of three components: the preamble, the header, and the payload. When transmitting the packet,
the preamble is sent first, followed by the header and finally by the payload. An LSB is the first bit
transmitted.
Figure 11 — PHY layer frame format
7.1.2 Preamble
As shown in Figure 12, the preamble consists of two portions: a 8-bit wake-up sequence of [0000 0000]
and a 16-bit synchronization sequence consisting of a 12-bit sequence of [000000000000] followed by
a 4-bit sequence of [1010]. The wake-up sequence is only included in the preamble of RR packet in the
request period. The synchronization sequence can be used for the packet acquisition, the symbol timing
and the carrier frequency estimation.
The preamble is coded using the TYPE 0 defined in 7.1.3. The wake-up sequence is modulated by ASK,
but the synchronization sequence by BPSK.
Figure 12 — Preamble format
7.1.3 Header
The header is added after the preamble to convey information about a payload. As shown in Figure 13,
the header is composed of 24 bits. Bits 0-2 are the data rate and coding field. Bits 3-10 are the payload
data length field. Bits 16-23 are a CRC-8 HCS. The details are defined in Table 3.
The header is coded using the TYPE 0 defined in 7.1.3.
12 © ISO/IEC 2014 – All rights reserved

Figure 13 — Header format
Table 3 — Header definition of physical layer
Bit Content Description
Specifies the data rate and coding at which the payload is received
b2-b0 Data rate and coding
(see Table 4)
Specifies the number of octets in the payload (which does not include
b10-b3 Payload data length
the FCS)
b15-b11 Reserved Reserved and set to zero
b23-b16 HCS Provides a CRC-8 HCS (see 7.1.3.3)
7.1.3.1 Data rate and coding
Depending on the data rate and coding used, bits 0-2 are set according to the values in Table 4. The
details of TYPE 0~7 are described in 7.2.2.
Table 4 — Definition of the data rate and coding
Type Value (b2 b1 b0) Data rate Coding method
TYPE 0 000 1 Kbps Manchester
TYPE 1 001 2 Kbps Manchester
TYPE 2 010 4 Kbps Manchester
TYPE 3 011 2 Kbps NRZ-L + Scrambling
TYPE 4 100 4 Kbps NRZ-L + Scrambling
TYPE 5 101 8 Kbps NRZ-L + Scrambling
TYPE 6 110 Reserved —
TYPE 7 111 Reserved —
7.1.3.2 Payload data length
The payload data length is an unsigned 8-bit integer that indicates the number of octets in the payload,
which does not include the FCS. It ranges from 0x00 to a maximum of 0xFF bytes.
7.1.3.3 Header check sequence (HCS)
The header is checked for errors using a CRC-8 HCS. The HCS covers a data rate and coding, a payload
data length and a reserved 5-bit. The primitive polynomial is given as,
2 3 4 7 2 5 7 8
g(D) = (1 + D) (1 + D + D + D + D ) = 1 + D + D + D + D + D
A schematic of the processing order is shown in Figure 14. The registers are initialized to all zeros.
Data is accumulated while the switch S in Figure 14 is being placed at ‘1’; when the last bit has been
accumulated, the switch S goes to ‘2’ and HCS is transmitted from the register beginning with in D .
© ISO/IEC 2014 – All rights reserved 13

Figure 14 — Encoder of header check sequence
7.1.4 Payload
As shown in Figure 15, the payload consists of a variable length data and the FCS. If the payload data
length field in the header has zero, FCS is not sent.
Figure 15 — Format of payload
7.1.5 Frame check sequence (FCS)
The payload is checked for errors using a CRC-16 FCS defined in Table 5. The FCS covers a variable length
16 12 5
data. The primitive polynomial is X + X + X + 1. The registers are initialized to all ones. The frame
check sequence is obtained by inverting the calculated CRC-16 bits.
Table 5 — Cyclic redundancy check for frame check sequence
CRC type Length Polynomial Preset Residue
16 12 5
ISO/IEC 13239 16 Bit X + X + X + 1 0xFFFF 0x1D0F
7.2 Coding and modulation
7.2.1 Coding
7.2.1.1 Manchester coding
Manchester code has a transition in the middle of every bit interval whether a one or a zero is being sent.
A zero is represented by a half-bit-wide pulse positioned during the first half to the bit interval. A one is
represented by a half-bit-wide pulse positioned during the second half to the bit interval.
14 © ISO/IEC 2014 – All rights reserved

Figure 16 — Definition of Manchester coding
7.2.1.2 NRZ-L coding
With NRZ-L(Level) a zero is represented by zero level and a one is represented by one level.
Figure 17 — Definition of NRZ-L coding
7.2.1.3 Scrambling
A scrambler is used to whiten only a payload data encoded by NRZ-L. The primitive polynomial g(D) is
given as,
14 15
g(D) = 1 + D + D
where D is a bit delay element. Figure 18 shows the scrambler’s block diagram. d is generated as follows,
k
dd=⊕d
kk−−14 k 15
where ''⊕ denotes modulo-2 addition. The scrambler is initialized to a seed value, 0xFFFF. The scrambled
data bit, b , is obtained as:
k
bs=⊕d
kk k
where s represents the non-scrambled data bit.
k
© ISO/IEC 2014 – All rights reserved 15

Figure 18 — Scrambler block diagram
7.2.2 The data rate and coding type
The physical layer supports 8 Types as shown in Table 4.
Preamble and header are encoded by TYPE 0 using Manchester coding at a data rate of 1Kbps, however
payload is encoded using the appropriate data rate of 1, 2, 4, or 8 Kbps and coding. The data rate and
coding type of the payload are specified in the data rate and coding field in the header.
7.2.3 Modulation
The communications between MFAN-C and MFAN-N uses either ASK modulation or BPSK modulation.
7.2.3.1 ASK modulation
As shown in Figure 19, the encoded serial input data is converted into a number representing one of the
two ASK constellation points. (ω is the carrier frequency of MFAN.)
c
Figure 19 — ASK modulation diagram
7.2.3.2 BPSK modulation
The transmission between MFAN-C and MFAN-N uses the BPSK modulation. As shown in Figure 20, the
encoded serial input data is converted into a number representing one of the two BPSK constellation
points. (ω is the carrier frequency of MFAN.)
c
16 © ISO/IEC 2014 – All rights reserved

Figure 20 — BPSK modulation diagram
7.2.4 The coding and modulation process
7.2.4.1 The coding and modulating process of the preamble
The preamble sequence (see 7.1.2) is encoded using the TYPE 0 (see 7.2.2). The wake-up sequence, if any,
is modulated by ASK and the synchronization sequence by BPSK.
Figure 21 — The coding and modulation process of the preamble
7.2.4.2 The coding and modulation process of the header
As shown in Figure 22, header is formatted by appending a data rate and coding, a payload data length,
a 5-bit zero (see 7.1.3) and HCS value. The resulting combination is encoded using the TYPE 0 (see 7.2.2)
and then modulated by BPSK.
Figure 22 — The coding and modulation process of header
7.2.4.3 The coding and modulation process of the payload
As shown in Figure 23, payload is formatted by appending data and FCS value, which is calculated over
the data. The resulting combination is encoded using the TYPE I (I = 0~7) (see 7.2.2) and then modulated
by BPSK.
Figure 23 — The coding and modulation process of payload
© ISO/IEC 2014 – All rights reserved 17

8 MAC layer frame format
8.1 General
The MAC frame of MFAN consists of the frame header and the frame body. The frame header has
information for data among MFAN-Ns, and the frame body has the data for transmissions between
MFAN devices.
8.2 Frame format
All frame of MAC consists of the frame header and the frame body as shown in Figure 24.
a) Frame header: Consists of the MFAN ID, frame control, source node ID, destination node ID, and
sequence number. The frame header can be used for the data transmission.
b) Frame body: Consists of the payload that contains the data for transmissions between MFAN devices
and the FCS used to check errors within the payload.
Unit: Byte
Figure 24 — MAC layer frame format
8.2.1 Frame header
Frame header has information for the transmission/reception of frames and flow control.
8.2.1.1 MFAN ID
As shown in Figure 24, MFAN ID field consists of 1 byte and is used to identify networks.
8.2.1.2 Frame control
Frame control fields consist of the frame type, the acknowledgement policy, the first fragment, the last
fragment, and the protocol version; its format is shown in Figure 25.
Unit: Bit
Figure 25 — Format of frame control field
Each field is explained as follows:
a) Frame type field consists of 3 bits; refer to 8.3 for the details on frame types.
18 © ISO/IEC 2014 – All rights reserved

b) Acknowledgement policy field consists of 2 bits; in the case where the received frame is an
acknowledgement frame, it indicates the policy of the received acknowledgement frame,
otherwise it indicates the policy of the acknowledgement frame for a destination node.
The following shows the acknowledgement policy:
1) No acknowledgement: Destination node does not acknowledge the transmitted frame, and the
source node considers the transmission successful regardless of the transmission result. Such
method can be used in the frame that is transmitted for 1:1 or 1:N, transmission which do not
required the acknowledgement.
2) Single acknowledgement: The destination node that received the frame sends an
acknowledgement frame as a response to the source node after an SIFS. This acknowledgement
policy can only be used for 1:1 transmission.
3) Multiple acknowledgement: The destination node that received the frames sends an
acknowledgement frame as a response to the multiple source nodes after an SIFS. This
acknowledgement policy can be used for 1:N transmission.
4) Data acknowledgement: The destination node that received the data frame sends data
acknowledgement frame as a response to the source node after an SIFS. This acknowledgement
policy can only be used for 1:1 data transmission.
c) First fragment field is 1 bit; ‘1’ indicates that frame is the start of the request, response or data
packet from a higher layer, while ‘0’ means that it is not the start.
d) End fragment field is 1 bit; ‘1’ indicates that frame is the end of the request, response or data packet
from a higher layer, while ‘0’ means that it is not the end.
e) Protocol version field consists of 2 bits, and the size and location are fixed regardless of the protocol
version of the system. The present value is 0,
...