ARIB STD-T108
ARIB STD-T108

ENGLISH TRANSLATION
920MHz-BAND
TELEMETER, TELECONTROLAND DATA TRANSMISSION RADIOEQUIPMENT

ARIB
ARIB

STANDARD

STD-T108

Version 1.0
Version 1.2

Version 1. 2

February 14th 2012
January 22th 2018

Association of Radio Industries and Businesses

General Notes to the English translation of ARIB Standards and Technical Reports
1. The copyright of this document is ascribed to the Association of Radio Industries andBusinesses(ARIB).
2. All rights reserved. No part of this document may be reproduced, stored in a retrieval system, ortransmitted, in any form or by any means, without the prior written permission of ARIB.
3. The ARIB Standards and ARIB Technical Reports are usually written in Japanese and resolved by
the ARIB Standard Assembly. This document is a translation into English of the resolved document
for the purpose of convenience of users. If there are any discrepancies in the content, expressions,etc., between the Japanese original and this translated document, the Japanese original shallprevail.
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at the ARIB Standard Assembly, which meets several times a year. Adopted ARIB Standards andTechnical Reports, in their original language, are made publicly available in hard copy, CDs or
through web posting, generally in about one month after the date of approval. The original
document of this translation may have been further revised and therefore users are encouraged tocheck the latest version at an appropriate page under the following
URL:
http://www.arib.or.jp/english/index.html

ARIB STD-T108

Introduction
With participation of radio communication equipment manufacturers, broadcasting
equipment manufacturers, telecommunication operators, broadcasters and general equipment
users, Association of Radio Industries and Businesses (ARIB) defines basic technicalrequirements for standard specifications of radio equipment, etc. as an "ARIB STANDARD" inthe field of various radio systems.
In conjunction with national technical standards which are intended for effective spectrum
utilization and avoidance of interference with other spectrum users, an ARIB STANDARD isintended as a standard for use by a private sector compiling various voluntary standards
regarding the adequate quality of radio and broadcasting service, compatibility issues, etc., andaims to enhance conveniences for radio equipment manufacturers, telecommunication
operators, broadcasting equipment manufacturers, broadcasters and general users.
A

ARIB

STANDARD

hereinispublished

as"920MHz-BAND

TELEMETER,TELECONTROL AND DATA TRANSMISSION RADIO EQUIPMENT " In order to ensure
fairness and transparency in the defining stage, the standard was set by consensus of thestandard council with participation of interested parties including radio equipment
manufacturers, telecommunication operators, broadcasters, testing organizations, generalusers, etc. with impartiality.
Radio equipment defined in this standard utilize 915 to 930 MHz. With the radio systemdescribed in the ARIB STANDARD herein, the electrical power spreads over a wide bandwidth,
and therefore it is necessary to avoid radio interference to various radio systems in the band. Inorder to avoid harmful radio interferences to other radio systems, "Operational rule" is also
documented and attached hereto as a appendix material.
It is our sincere hope that the standard would be widely used by radio equipment
manufacturers, testing organizations, general users, etc.
This standard has been newly established, following the amendment notification of RadioLaw on December 14, 2011. This standard is based on ARIB STD-T96, “950 MHz-Band
Telemeter, Telecontrol and Data Transmission Radio Equipment for Specified Low PowerRadio Station,” the version 1.0 of which was established on June 6, 2008 and revised to theversion 1.1 on July 15, 2010. Thereafter, this standard has been revised to the version 1.1 in
response to the amendment notification Radio Low on September 11, 2017. Furthermore, it has
been revised to the version 1.2 for expansion of radio usage.

ARIB STD-T108

The radio channel assignment of radio stations with antenna power no greater than 1 mW
and with central frequencies 916.0 MHz to 926.8 MHz, and the boundary frequency (922.3 MHz
in this standard) between different channel sharing techniques defined on radio stations withantenna power no greater than 1 mW, 20 mW or 250 mW, may be revised in future, reflectingchanges of international regulations or prevalence of each category of radio stations.

ARIB STD-T108

Contents
Introduction
Part 1 Land mobile stations. ........................................................................................................... 1-1
Part 2 Specified low-power radio stations ...................................................................................... 2-1
Appendix Operational rule .............................................................................................................. 3-1

ARIB STD-T108

Part 1 Land mobile stations

ARIB STD-T108

Contents

Chapter 1 General items ............................................................................................................. 1
1.1 Overview ............................................................................................................................. 1
1.2 Scope of application ........................................................................................................... 1
1.3 Definitions of terminology ................................................................................................. 1
Chapter 2 Overview of the standard system ............................................................................. 3
2.1 Standard system ................................................................................................................ 3
2.1.1 Structure of the standard system .............................................................................. 3
2.1.2 Operation of the standard system.............................................................................. 4
2.2 Key parameters and functionality of the standard system ............................................ 6
Chapter 3 Technical requirements for radio equipment .......................................................... 7
3.1 General conditions ............................................................................................................. 7
3.1.1 Communication method .............................................................................................. 7
3.1.2 Contents of communications ...................................................................................... 7
3.1.3 Emission class ............................................................................................................. 7
3.1.4 Operating frequency band...................................................................................... 7

3.1.5 Usage environment condition..................................................................................... 7
3.2 Transmitter ........................................................................................................................ 7
3.2.1 Antenna power....................................................................................................... 7

3.2.2 Tolerance for antenna power
3.2.3 Radio channel.................................................................................. 7......................................................................................................... 7

3.2.4 Frequency tolerance................................................................................................ 9

3.2.5 Modulation method ................................................................................................... 10
3.2.6 Permissible value for occupied bandwidth
3.2.7 Adjacent channel leakage power......................................................... 10........................................................................ 11

3.2.8 Permissible Values for Spurious Emission / Unwanted Emission Intensity ....... 13
3.3 Receiver ............................................................................................................................ 13
3.4 Controller.......................................................................................................................... 14
3.4.1 Transmission time control equipment .................................................................. 14
3.4.2 Carrier sense.......................................................................................................... 15

3.4.3 Skipping carrier sense in a response............................................................... 15

3.4.4 Interference prevention function ............................................................................. 16
3.5 Cabinet.............................................................................................................................. 17－1-i－

ARIB STD-T108

3.6 Connection to telecommunication circuit ....................................................................... 17
3.7 Antenna ............................................................................................................................ 17
Chapter 4 Compliance of radiation protection ........................................................................ 19
Chapter 5 Measurement methods ......................................................................................... 21－1-ii－

ARIB STD-T108

Chapter 1 General items
1.1 Overview
Among the land mobile service defined in Article 16 of the Regulations for Enforcement of theRadio Law (No 62 of the Ordinance of the Ministry of Internal Affairs and Communications,2017) (Notification 405 of the Ministry of Posts and Telecommunications, 1994 : Revision by
Notification 288 of Ministry of Internal Affairs and Communications, 2017), this standard
specifies on the telemeter, telecontrol and data transmission radio equipment that uses thefrequency of 920.5MHz or more and 923.5MHz or less specified in Article 49, Clause 34 of theOrdinance Regulating Radio Equipment Regulations.

1.2 Scope of application
A telemeter, telecontrol and data transmission radio equipment consists of radio equipment,
data processing equipment and power supply equipment as shown in Figure 1-1. This standard
specifies the technical requirements of the radio equipment.

Radio equipment
Antenna
Data processing
equipment

Transmitter
Controlequipment
ReceiverPower supply
Chassisequipment

Figure 1-1 Structure of telemeter, telecontrol and data transmission radio equipment

1.3 Definitions of terminology
In this standard, ‘RL’ refers to the Radio Law, ‘RERL’ refers to the Regulations for Enforcementof the Radio Law, ‘ORE’ refers to the Ordinance Regulating Radio Equipment, ‘OTRCC’ refers
to the Ordinance Concerning Technical Regulations Conformity Certification etc. of Specified
Radio Equipmentand ‘NT’ refers to a Notification of the Ministry of Posts and－1-1－

ARIB STD-T108

Telecommunications before 2000 or a Notification of the Ministry of Internal Affairs andCommunications after 2001.

－1-2－

ARIB STD-T108

Chapter 2 Overview of the standard system
2.1 Standard system
Standard systems are categorized into a short range communication system and an active tag
system. In the following section these systems are described respectively.

2.1.1 Structure of the standard system(1) Short range communication system
The standard system of a short range communication consists of plural radio stations asshown in Figure 2-1.
Radio
stationRadio
stationRadio
station
Radio

Radio

stationstationFigure 2-1 Structure of a standard short range communication system

In this system, radio stations are connected each other and construct a network. In thisnetwork, both of pier to pier communication and broadcast communication are possible.
Besides, not only direct transmission but also multi hop transmission is possible.

－1-3－

ARIB STD-T108(2) Active tag system
The standard system of active tags consists of a reader/writer and plural active tags as shownin Figure 2-2.
Active tag

Active tag

Reader/Writ

Active tag

Figure 2-2

Active tag

Structure of a standard active tag system

In this system, one way or two way transmission between an active tag and a reader/writeror between active tags in arbitrary timing is possible.

2.1.2 Operation of the standard system(1) Short range communication system
Short range communication system is a short-range and low rate wireless PAN (Personal
Area Network) system with the purpose of low power consumption and low cost
implementation such as IEEE802.15.4 which is an existing standard in USA.

As an

example of low rate wireless PAN system using IEEE802.15, there is Wi-SUN which is used
for Smart meter or various IoT (Internet of Things).
Recently, new various standards which can cover wide area with low power as LPWA (LowPower Wide Area) are proposed and these standards are also included.
It is supposed to be used for home security, safety and security of children and elder people,
personal healthcare, home and building control, factory automation and monitoring, hospitalmanagement, auto meter reading and outdoor monitoring on the network consisting of
wireless sensor nodes and/or wireless actuator nodes which control various kinds ofequipment－1-4－

ARIB STD-T108(2) Active tag system
The active tag system is a system that is able to emit a radio signal autonomously by using
energy stored within itself such as battery. In comparison with the passive tag system whose
reader/writer needs large output power to activate a tag, the active tag system can reduce theoutput power and extend the communication area to the wide range.
Most of the existing active tag systems in Japan use 300MHz band (Specified low power radio
station or extremely low power radio station), 400MHz band (Specified low power radio
station) and 2.4GHz band. 433MHz band is opened only for international transportation use.
Currently most of the domestically existing active tag system is used to transmit a tag ID
from an active tag. However, advanced functionalities such as tags with sensor, localization,
bi-directional communication, as well as rewriting the information to tag are developing. It is
supposed to be used for security support to children on their way, security support in
shopping mall, admission control to dangerous area, asset management, management ofvehicles and parking lots and process control.
There are passive tag systems in 920MHz band. In these systems responder (tag) can notemit radio signal autonomously and transmit a response signal by using only power of carrier
signal received from the interrogator. These systems are out of scope of this standard. Thesekind of passive tag systems are specified in ARIB STD-T106 and ARIB STD-T107.

－1-5－

ARIB STD-T108

2.2 Key parameters and functionality of the standard system
Key parameters and functionality of the standard system are shown in Table 2-1.

Table 2-1 Key parameters and functionality of the standard system

Item

Parameters and functionality

Frequency band

920.5MHz or more and 923.5MHz orless (note)

Transmission power

250 mW or lessTransmission
methodContents

Data signal

Modulation
systemNot specified

Antenna gain

3dBi or less (absolute gain)
However, in case EIRP is less than
27dBm (the value of 3 dBi plus 250
mW of antenna power), it is allowed
to fill in the gap by the antenna gain.

(Note) EIRP defined as the product of transmitter power and the antenna gain, andshould be take into account the deviation in transmitter power characteristic.

－1-6－

ARIB STD-T108

Chapter 3 Technical requirements for radio equipment
The standard includes both “national technical criteria (mandatory)” and “private optional
criteria”. A regulation and an article providing a legal basis are quoted for the former..

3.1 General conditions
3.1.1 Communication method
One-way method, simplex method, duplex method, semi-duplex method or broadcast

3.1.2 Contents of communications
Primarily the signals for telemeter, telecontrol and data transmission system.

3.1.3 Emission class
Not specified.
(ORE: article 49-34)

3.1.4 Operating frequency band

(Ministerial ordinance of MIC No.62, 2017)
920.5 MHz or more and 923.5 MHz or less

3.1.5 Usage environment condition
Not specified.

3.2 Transmitter(ORE: article 49-34)

3.2.1 Antenna power(Ministerial ordinance of MIC No.62, 2017)
It shall be 250 mW or less.
(ORE: article 14)

3.2.2 Tolerance for antenna power(Ministerial ordinance of MIC No.62, 2017)+20%, -80%
(ORE: article 49-34)

3.2.3 Radio channel(Ministerial ordinance of MIC No.62, 2017)
A radio channel shall consist of up to 5 consecutive unit radio channels which are defined that
their center frequencies are located from 920.6.MHz to 923.4 MHz with 200 kHz separation and－1-7－

ARIB STD-T108

their bandwidth are 200 kHz.
However, it is prohibited to simultaneously use both the unit radio channels giving priority topassive tag system whose center frequencies are located from 920.6 MHz to 922.2 MHz(Channel numbers are from 24 to 32) and the unit radio channels whose center frequencies arelocated 922.4 MHz or more (Channel numbers are 33 or more)
The center frequencies of radio channels are shown through Table 3-1 to Table 3-5.
(1) The case of using one unit radio channel

Table 3-1 Center frequency of radio channel using one unit radio channel(Bandwidth: 200 kHz)

Unit radio channel
number
24
25
26
27
28
29
30
31

Center frequency
(MHz)
920.6
920.8
921.0
921.2
921.4
921.6
921.8
922.0

Unit radio channel
number
32
33
34
35
36
37
38

Center frequency
(MHz)
922.2
922.4
922.6
922.8
923.0
923.2
923.4

(2) The case of using two unit radio channels
Table 3-2 Center frequency of radio channel using two unit radio channels(Bandwidth:400 kHz）

Unit radio channel
number
24,25
25,26
26,27
27,28
28,29
29,30
30,31

Center frequency
(MHz)
920.7
920.9
921.1
921.3
921.5
921.7
921.9

Unit radio channel
number
31,32
33,34
34,35
35,36
36,37
37,38

Center frequency
(MHz)
922.1
922.5
922.7
922.9
923.1
923.3

(3) The case of using three unit radio channels
Table 3-3 Center frequency of radio channel using three unit radio channels－1-8－ARIB STD-T108(Bandwidth: 600 kHz）

Unit radio channel
number24,25,26
25,26,27
26,27,28
27,28,29
28,29,30
29,30,31

Center frequency
(MHz)
920.8
921.0
921.2
921.4
921.6
921.8

Unit radio channel
number30,31,32
33,34,35
34,35,36
35,36,37
36,37,38

Center frequency
(MHz)
922.0
922.6
922.8
923.0
923.2

(4) The case of using four unit radio channels

Table 3-4 Center frequency of radio channel using four unit radio channels(Bandwidth: 800 kHz）

Unit radio channel
number24,25,26,27
25,26,27,28
26,27,28,29
27,28,29,30
28,29,30,31

Center frequency
(MHz)
920.9
921.1
921.3
921.5
921.7

Unit radio channel
number29,30,31,32
33,34,35,36
34,35,36,37
35,36,37,38

Center frequency
(MHz)
921.9
922.7
922.9
923.1

(5) The case of using five unit radio channels

Table 3-5 Center frequency of radio channel using five unit radio channels(Bandwidth: 1000 kHz)

Unit radio channel
number24,25,26,27,28
25,26,27,28,29
26,27,28,29,30
27,28,29,30,31

Center frequency
(MHz)
921.0
921.2
921.4
921.6

Unit radio channel
number28,29,30,31,32
33,34,35,36,37
34,35,36,37,38

Center frequency
(MHz)
921.8
922.8
923.0

(ORE: article 5, attached table No.1)

3.2.4 Frequency tolerance(Ministerial ordinance of MIC No.62, 2017)
It shall be within 20 x 10-6.
However, in case of using one unit radio channel, the frequency band width is defined as“Designated Frequency Bandwidth”, and the definition of frequency tolerance as above shallnot be applied. (Designated Frequency Bandwidth: is defined as frequency band width which is－1-9－

ARIB STD-T108

equal to the sum of allowable occupied frequency bandwidth and the twice of absolute frequency
bandwidth, under the condition that the center frequency of the designated frequency
bandwidth is equal to the center frequency of the radio channel.)

3.2.5 Modulation method
It shall not be specified.
(ORE: article 6, attached table No.2)

3.2.6 Permissible value for occupied bandwidth(Ministerial ordinance of MIC No.62, 2017)
It shall be (200 x n) kHz or less. (n is a number of unit radio channels constituting the radio
channel and is an integer from 1 to 5.)－1-10－

ARIB STD-T108(ORE: article 49-34)

3.2.7 Adjacent channel leakage power(Ministerial ordinance of MIC No.62, 2017)(1) Frequency band of signal in use is from 920.5MHz to 922.3MHz.
i)

Spectral power at the edge of a radio channel: It shall be +4dBm or less.

ii)

Leakage power in unit radio channel adjacent to a radio channel (200kHz):It shall be –5dBm or less.
Unit : dBm / 100kHz

200 kHz(200×n) kHz

200 kHz30
Power at the edge:+４dBm or less

20
10
0

Spurious emission strength(920.3MHz to 924.3MHz)－29dBm／100ｋHz

-10
-20
-30
-40

Adjacent channel
leakage power:–5dBm or less

Unit:
kHz

-50
Lower adjacentunit channel

fc(Centerfrequency)(中心周波数)fc－200－100×(n－1)

Upper adjacentunit channel

fc＋200＋100×(n－1)(Note: Center frequency is one of frequencies shown in Table 3.1 to Table 3.5 of
3.2.3 Radio channel and n is the number of unit radio channels
constructing a radio channel.)Figure 3-1 Channel mask of a radio channel whose frequency is from 920.5MHz to 922.3MHz.

－1-11－

ARIB STD-T108

Frequency band of signal in use is from 922.3MHz and to 923.5MHz.
i)

Leakage power in unit radio channel adjacent to a radio channel (200kHz):It shall be –5dBm or less.

Unit : dBm / 100kHz

200kHz(200×n)kHz

200kHz30
20
10
Spurious emission
strength(920.3MHz to 924.3MHz):–29dBm / 100kHz

0
-10
-20
-30
-40

Unit :
kHz-50
Adjacent channel
leakage power :–5dBm or less

Lower adjacentunit channel

fc(中心周波数)(Centerfrequency)

fc－100×n

fc＋100×n

Upper adjacentunit channel(Note: Center frequency is one of frequencies shown in Table 3.1 to Table 3.5 of
3.2.3 Radio channel and n is a number of unit radio channels constructing
a radio channel.)Figure 3-2 Channel mask of a radio channel whose frequency is from 922.3MHz to 923.5MHz.

－1-12－

ARIB STD-T108

3.2.8 Permissible Values for Spurious Emission / Unwanted Emission Intensity(ORE: article 7, Attached table No.3-24)(Ministerial ordinance of MIC No.62, 2017)
Spurious Emission / Unwanted Emission Intensity at the antenna input shall be less than thevalue in Table 3-6.

Table 3-6 Permissible Values for Spurious Emission / Unwanted Emission Intensity (Antenna input)

Spurious Emission /Unwanted Emission
Intensity (average power)－36 dBm

Frequency bandf <= 710 MHz

Reference
bandwidth
100 kHz

710 MHz < f <= 900 MHz－55 dBm

1 MHz

900 MHz < f <= 915 MHz－55 dBm

100 kHz915 MHz < f <= 920.3 MHz
920.3 MHz < f <= 924.3 MHz(except for |f-fc| <= (200+100xn) kHz)924.3 MHz < f <= 930 MHz－36 dBm

100 kHz－29 dBm

100 kHz－36 dBm

100 kHz930 MHz < f <= 1000 MHz－55 dBm

100 kHz

1000 MHz < f <= 1,215 MHz－45dBm1 MHz

1,215 MHz < f－30 dBm

1 MHz

3.3 Receiver
Limit on Secondary Radiated Emissions, etc.

(ORE: article 24-15)(Ministerial ordinance of MIC No.62, 2017)

Limit on Secondary Radiated Emissions shall be value in Table 3-7 or less.

Table 3-7 Limit on Secondary Radiated Emissions at receiver

Limit on Secondary
Radiated Emissions(Antenna input)－54 dBm

Frequency bandf <= 710 MHz

Reference
bandwidth
100 kHz

710 MHz < f <= 900 MHz－55 dBm

1 MHz

900 MHz < f <= 915 MHz－55 dBm

100 kHz915 MHz < f <= 930 MHz－54 dBm

100 kHz930 MHz < f <= 1000 MHz－55 dBm

100 kHz

1000MHz < f－47 dBm

1 MHz－1-13－

ARIB STD-T108

3.4 Controller
Controller shall have functions that comply with the conditions specified in this section
described below.
(ORE: article 49-34, NT: No.292, 2017)

3.4.1 Transmission time control equipment(1) In case the 5ms or more carrier sense is required:If the center frequency is from 920.6MHz to 923.4MHz, radio equipment shall stop its
emission of radio wave less than 4s after it starts to emit radio wave. It shall wait 50ms ormore for the consecutive emission.
Meanwhile, it may emit radio wave again without waiting 50ms, if the emission time is lessthan 4s after its first emission, and this re-emission is started after 128µs or more carrier
sense, and is finished less than 4s after its first emission.
In case the center frequency is between 922.4MHz and 923.4MHz, the total transmission
time per an hour shall be 360 sec or less.
(2) In case the 128µs or more and less than 5ms carrier sense time is required:If the center frequency is from 922.4MHz to 923.4MHz, the following conditions shall besatisfied.
1. Using one unit radio channel: radio equipment shall stop its emission of radio wave lessthan 400ms after it starts to emit radio wave. The sum of emission time per arbitrary one
hour shall be 360s or less.
Meanwhile, if the emission time is more than 200ms, it shall wait for ten times or more of
the former emission time. If the emission time is more than 6ms and is 200 ms or less, it shallwait for 2ms for the consecutive emission.
In case the next emission is different from the previous center frequency channel, it is notnecessary to wait for ten times, and the next emission can be performed after 2ms of previous
emission.
2. Using two unit radio channels: radio equipment shall stop its emission of radio wave lessthan 200ms after it starts to emit radio wave. The sum of emission time per arbitrary one
hour shall be 360s or less. Meanwhile if the emission time is more than 3ms, it shall wait for
2ms for the consecutive emission.
3. Using 3, 4, or 5 unit radio channels: radio equipment shall stop its emission of radio wave
less than 100ms after it starts to emit radio wave. The sum of emission time per arbitrary one
hour shall be 360s or less. Meanwhile if the emission time is more than 2ms, it shall wait 2ms－1-14－

ARIB STD-T108

for the consecutive emission.
(ORE: article 49-34, NT: No.292, 2017)

3.4.2 Carrier sense(1) Radio equipment shall check if the interference exists by the career sense procedure
before its new transmission.
(2) Carrier sense time shall be 128 µs or more.
(3) Carrier sense level that is amount of received power at all of unit radio channels
included in the radio channel to emit shall be -80 dBm at the antenna input. When the
carrier sense level is not less than -80 dBm, radio equipment shall not transmit any
radio wave.
(ORE: article 49-34, NT: No.292, 2017)

3.4.3 Skipping carrier sense in a response

If the emission is a response to request by other radio equipment, and following conditions are
satisfied, carrier sense is not necessary, and the response time is not included in the sum ofemission time per arbitrary one hour.
1. Using one unit radio channel: the emission starts within 2ms after the reception of therequest is completed, and the emission ends within 50ms.
2. Using 2, 3, 4, or 5 unit radio channels: the emission starts within 2ms after the reception of
the request is completed, and the emission ends within 5ms.
Figure 3-3 shows concept of a response that does not require carrier sense.

Carrier sense
Station A

Data transfer(Note1)

Response completion time
Station B

Response(Note2)

Response start time
Figure 3-3

Concept of a response that does not require carrier sense(Note1) In Station A, measurement of pause duration shall start at completion of emission－1-15－

ARIB STD-T108

at Station A.
(Note2) In Station B, measurement of pause duration shall start at completion of responseat Station B.

Table 3-8 shows possible combinations of sending control parameters specified by 3.4.1 Sending
control, 3.4.2 Carrier sense and 3.4.3 Skipping carrier sense in a response.

Table 3-8 Possible combinations of sending control parameters specified by 3.4.1 Sending control, 3.4.2
Carrier sense and 3.4.3 Skipping carrier sense in a response

Antennapower

AppliedCH
number24-32
33-38

Unit CH
bandwidth

CH usedin abundleCarriersense time

Sending
duration

Pause
duration

1～5ch

5ms ormore

4s(Note1)

50ms

200kHzTen times ormore of theMore thanformer200ms, andtransmitting
400ms or lesstime or2ms (Note3)
More than
6ms, and2ms
200ms or less
6ms or less
None
More than
3ms, and2ms
200ms or less
3ms or less
None
More than2ms, and
2ms
100ms or less
2ms or less
None

1ch
250mW or
less
33-38

128μs
or more200kHz2ch

3～5ch

The sum of Conditions of response to(Note 2)emission time skip carrier sense
per arbitrary Completion
Start time
1 hourtime
24-32:None33-38:360sec――
or less

50ms or less360sec or
less

2ms or less

5ms or less

(Note1) It may emit again without waiting 50ms, if it is within 4s after its first emission. The
emission shall start after carrier sense is performed for 128µs or more and the emission
shall finish within this 4s interval.
(Note2) Emission time of a response that satisfies the conditions is not included in the sum ofemission time per arbitrary one hour.
(Note3) Instead of ten times, 2ms can be applied in case the next emission is different center
frequency channel as the previous one.

3.4.4 Interference prevention function
The radio equipment shall automatically transmit/receive identification codes.

－1-16－

ARIB STD-T108(ORE: article 49-34)

3.5 Cabinet(Ministerial ordinance of MIC No.62, 2017)
The high frequency circuit and modulation modules except for antenna shall be structured not
to be opened easily.

3.6 Connection to telecommunication circuit(OCTF: article 9, NT: No.295, 2017)
Radio equipment shall satisfy the following conditions.
(1) It shall have identification code which shall be 32 bits length or more.
(2) Except for particular case which is defined outside of the specification, it shall makedecision if channel is used or not before using that channel. Only if that decision is "channel
is not used", it can set a communication path on its channel.
(ORE: article 49-34)

3.7 Antenna(Ministerial ordinance of MIC No.62, 2017)
Antenna gain

3dBi or less (absolute gain)
However, in case EIRP is less than 27dBm, it is allowed to fill in the gap
by the antenna gain.
EIRP defined as the product of transmitter power and the antenna gain,
and should be take into account the deviation in transmitter power
characteristic.

－1-17－

ARIB STD-T108(Intentionally blanked)－1-18－

ARIB STD-T108

Chapter 4 Compliance of radiation protection
RERL article 21-3Signal intensity means electric field strength, power flux density and magnetic field strength（hereinafter the same）.
It is set forth as that the place at which the signal intensity coming from radio equipment
exceed the value shown in table 4-1, protection facilities are required to guard person who are
there except for operator.
RERL attached table 2-3-2
Table 4-1 Reference value of electromagnetic field strength (RERL article 21-3)

Frequency
More than 300MHzand lessthan 1.5GHz

Electric
field
strength(V/m)
1.585 f1/2

Magnetic
field
strength(A/m)
1/2
f ／237.8

Power flux
density(mW/cm2)

Average Time(minute)f／15006Note1: Unit of f is in MHz.
Note 2: Electric field strength and Magnetic field strength should be filled in effective values.
NT: No.300,1999
S=(PG)/(40πR2)･K
P(W):Antenna power
G :Antenna gain
K : coefficient of reflectiona) no reflection K=1b) taking account of the refection from the ground K=2.56 (Frequency is higher than
76MHz)c) In case there are some buildings, towers, and something metal structure closearound the calculation points, please 6dB add from calculation results.
K=2.56×106/10 =10.2
The power flux density S at 923MHz is given as、
S=f/1500=923/1500=0.6153(mW/cm2)－1-19－

ARIB STD-T108

Therefore、The limited distance of radiation protection guideline can be described as
R=(PGK/40πS)1/2
The example of calculation results in case of 0.25W antenna power with 3dBi of antenna gain isshown in table 4-2.

Table 4-2 The example of calculation results of the limited distance by radiation protection guideline

Coefficientof reflection

Reflection circumstanceK

No-reflection
From the ground
From buildings towers, something of
metal that has possibility to makestrong reflection.

The limited distance ofradiation protection
guideline

1
2.56

R
0.08m
0.13m

10.2

0.26m

Some uncertain factors such as the layout and structure around the calculation point must be
considered. Especially some metallic objects located nearby antenna may make an impact on
calculation results.
Calculation requires the correspondence united with the situation of the field.
RERL article 21-3 doesn’t apply the following radio equipment.
Mobile radio equipment
Temporally radio equipment that is used in emergency case such as earthquake ortyphoonWhile the operation of Land mobile stations, if there is the area around the antenna at which
can not be meet radiation protection guideline, it is need to provision such as safety fence.
In fact, the maximum continues radiation time is limited as 4 second in this standard, it is
impossible to continue transmitting 6 minute shown in table 4-1.

－1-20－

ARIB STD-T108

Chapter 5 Measurement

methods

TELEC-T258, which is established based on Notification No. 88-2 of MIC by Telecom
Engineering Center, shall be applied. If the other method is specified by Notification of MIC orothers, it shall be also applied.

－1-21－

ARIB STD-T108

Part 2 Specified low-power radio stations

ARIB STD-T108

Contents
Chapter 1 General items ............................................................................................................. 1
1.1 Overview ............................................................................................................................. 1
1.2 Scope of application ........................................................................................................... 1
1.3 Definitions of terminology ................................................................................................. 1
Chapter 2 Overview of the standard system ............................................................................. 3
2.1 Standard system ................................................................................................................ 3
2.1.1 Structure of the standard system .............................................................................. 3
2.1.2 Operation of the standard system.............................................................................. 4
2.2 Key parameters and functionality of the standard system ............................................ 6
Chapter 3 Technical requirements for radio equipment .......................................................... 7
3.1 General conditions ............................................................................................................. 7
3.1.1 Communication method .............................................................................................. 7
3.1.2 Contents of communications ...................................................................................... 7
3.1.3 Emission class ............................................................................................................. 7
3.1.4 Operating frequency band...................................................................................... 7

3.1.5 Usage environment condition..................................................................................... 7
3.2 Transmitter ........................................................................................................................ 7
3.2.1 Antenna power......................................................................................................... 7

3.2.2 Tolerance for antenna power.................................................................................. 8

3.2.3 Radio channel ........................................................................................................... 8
3.2.4 Frequency tolerance.............................................................................................. 16

3.2.5 Modulation method ................................................................................................... 16
3.2.6 Permissible Value for Occupied Bandwidth
3.2.7 Adjacent channel leakage power........................................................ 16.......................................................................... 17

3.2.8 Permissible Values for Spurious Emission / Unwanted Emission Intensity........ 22
3.3 Receiver ............................................................................................................................ 23
3.4 Controller.......................................................................................................................... 23
3.4.1 Transmission time control equipment
3.4.2 Carrier sense............................................................. 23.......................................................................................................... 25

3.4.3 Skipping carrier sense in a response .................................................................... 25
3.4.4 Interference prevention function.......................................................................... 28

3.5 Cabinet.............................................................................................................................. 28
3.6 Connection to telecommunication circuit ....................................................................... 28－2-i－

ARIB STD-T108

3.7 Antenna ............................................................................................................................ 28
Chapter 4 Measurement methods ......................................................................................... 29－2-ii－

ARIB STD-T108

Chapter 1 General items
1.1 Overview
Among the Specified Low-Power Radio Stations defined in Article 6 of the Regulations for
Enforcement of the Radio Law (Revision by Ministerial ordinance No. 65 of Ministry of Internal
Affairs and Communications, 2008) and Notification 42 of Ministry of Posts andTelecommunications, 1989 (Revision by Notification 516 of Ministry of Internal Affairs andCommunications, 2011), this standard specifies on the telemeter, telecontrol and datatransmission radio equipment that uses the frequency of 915.9 MHz or more 929.7 MHz or lessspecified in Article 49, Clause 14-7 and Clause 14-8 of Ordinance Regulating Radio Equipment
Regulations.

1.2 Scope of application
A telemeter, telecontrol and data transmission radio equipment consists of radio equipment,
data processing equipment and power supply equipment as shown in Figure 1-1. This standard
specifies the technical requirements of the radio equipment.

Radio equipment
Antenna
Data processing
equipment

Transmitter
Controlequipment

Power

ReceiversupplyChassisequipment

Figure 1-1 Structure of telemeter, telecontrol and data transmission radio equipment

1.3 Definitions of terminology
In this standard, ‘RL’ refers to the Radio Law, ‘RERL’ refers to the Regulations for Enforcementof the Radio Law, ‘ORE’ refers to the Ordinance Regulating Radio Equipment, ‘OTRCC’ refers－2-1－ARIB STD-T108
to the Ordinance Concerning Technical Regulations Conformity Certification etc. of Specified
Radio Equipment, ‘OCTF’ refers to the Ordinance Concerning Terminal Facilities Etc. and ‘NT’refers to a Notification of the Ministry of Posts and Telecommunications before 2000 or a
Notification of the Ministry of Internal Affairs and Communications after 2001.

－2-2－

ARIB STD-T108

Chapter 2 Overview of the standard system
2.1 Standard system
Standard systems are categorized into a short range communication system and an active tag
system. In the following section these systems are described respectively.

2.1.1 Structure of the standard system(1) Short range communication system
The standard system of a short range communication consists of plural radio stations asshown in Figure 2-1.
Radio
stationRadio
stationRadio
station
Radio

Radio

stationstationFigure 2-1 Structure of a standard short range communication system

In this system, radio stations are connected each other and construct a network. In thisnetwork, both of pier to pier communication and broadcast communication are possible.
Besides, not only direct transmission but also multi hop transmission is possible.

－2-3－

ARIB STD-T108(2) Active tag system
The standard system of active tags consists of a reader/writer and plural active tags as shownin Figure 2-2.
Active tag

Active tag

Reader/Writ

Active tag

Figure 2-2

Active tag

Structure of a standard active tag system

In this system, one way or two way transmission between an active tag and a reader/writeror between active tags in arbitrary timing is possible.

2.1.2 Operation of the standard system(1) Short range communication system
Short range communication system is a short-range and low rate wireless PAN (Personal
Area Network) system with the purpose of low power consumption and low cost
implementation such as IEEE802.15.4 which is an existing standard in USA.
Wi-SUN etc. used in smart meters and various IoT (Internet of Things) networks is as an
example of the low rate wireless PAN system using IEEE802.15.4.
Moreover, various standards have been proposed in recent years as LPWA (Low Power WideArea) having high coverage area at lower power consumption and these are also included as apart of the short range communication system.
It is supposed to be used for home security, safety and security of children and elder people,
personal healthcare, home and building control, factory automation and monitoring, hospitalmanagement, auto meter reading and outdoor monitoring on the network consisting of
wireless sensor nodes and/or wireless actuator nodes which control various kinds ofequipment－2-4－

ARIB STD-T108(2) Active tag system
The active tag system is a system that is able to emit a radio signal autonomously by using
energy stored within itself such as battery. In comparison with passive tag system whose
reader/writer needs large output power to activate a tag, the active tag system can reduce theoutput power and extend the communication area to the wide range.
Most of the existing active tag systems in Japan use 300MHz band (Specified low power radio
station or extremely low power radio station), 400MHz band (Specified low power radio
station) and 2.4GHz band. 433MHz band is opened only for international transportation.
Currently most of the domestically existing active tag system is used to transmit a tag ID
from an active tag. However, advanced functionalities such as tags with sensor, localization,
bi-directional communication, as well as rewriting the information to tag are developing. It is
supposed to be used for security support to children on their way, security support in
shopping mall, admission control to dangerous area, asset management, management ofvehicles and parking lots and process control.
There are passive tag systems in 920 MHz band. In these systems responder (tag) can notemit radio signal autonomously and transmit a response signal by using only power of carrier
signal received from the interrogator. These systems are out of scope of this standard. Thesekind of passive tag systems are specified in ARIB STD-T106 and ARIB STD-T107.

－2-5－

ARIB STD-T108

2.2 Key parameters and functionality of the standard system
Key parameters and functionality of the standard system are shown in Table 2-1.

Table 2-1 Key parameters and functionality of the standard system

Item
Frequency band

Transmission power

Contents
Transmission
methodParameters and functionality
915.9 MHz or more and 916.9 MHz or
lessand 920.5 MHz or more and 929.7
MHz or less
20 mW or less.
However, 1mW or less if radio
channel in use includes 916.0 MHz –916.8 MHz or 928.15 MHz – 929.65
MHz
Moreover, given the radio equipment
is housed in a single cabinet and shallnot be opened easily, and its EIRP
(Note) is 16dBm or 3dBm or less(value when applying 20mW or 1mWof antenna power to the transmitting
antenna having absolute gain of
3dBi), transmission power of 250mW
or less is allowed.
Data signal

Modulation
systemAntenna gain

Not specified

3dBi or less (absolute gain)
However, in case EIRP (Note) is morethan 16dBm or 3dBm (value when
applying 20mW or 1mW of antenna
power to the transmitting antenna
having absolute gain of 3dBi), theexcess amount should be reduced by
the antenna gain and if it is 16 dBmor 3 dBm, and if it is 16dBm or 3dBmor less, it is allowed to fill in the gap
by the antenna gain

(Note) EIRP (Equivalent Isotropic Radiated Power) is the value when antenna power
is applied to the antenna gain and it includes the deviation of the antenna power.

－2-6－

ARIB STD-T108

Chapter 3 Technical requirements for radio equipment
The standard includes both “national technical criteria (mandatory)” and “private optional
criteria”. A regulation and an article providing a legal basis are quoted for the former.

3.1 General conditions
3.1.1 Communication method
One-way method, simplex method, duplex method, semi-duplex method or broadcast

3.1.2 Contents of communications
Primarily the signals for telemeter, telecontrol and data transmission system.

3.1.3 Emission class
Not specified.
(RERL: article 6-4)

3.1.4 Operating frequency band

(Ministerial ordinance of MIC No.162, 2011)
915.9 MHz or more and 916.9 MHz or less, and 920.5 MHz or more and 929.7 MHz or less

3.1.5 Usage environment condition
Not specified.

3.2 Transmitter(RERL: article 6, NT: No.42, 1989)

3.2.1 Antenna power(Revised NT: No.516, 2011)
It shall be 20 mW or less. However, it shall be 1 mW or less for radio channels consisting of atleast one of channels whose center frequencies are located from 916.0 MHz to 916.8 MHz orfrom 928.15 MHz to 929.65 MHz.
Moreover, given the radio equipment is housed in a single cabinet and shall not be opened
easily, and its EIRP is 16dBm or 3dBm or less (value applying 20mW or 1mW of antenna power
to the transmitting antenna having absolute gain of 3dBi) , transmission power of 250mW orless is allowed). Here, EIRP is the value when antenna power is applied to the antenna gain
and it includes the deviation of the antenna power.

－2-7－

ARIB STD-T108(ORE: article 14)

3.2.2 Tolerance for antenna power(Ministerial ordinance of MIC No.162, 2011)+20%, -80%
(ORE: article 49-14)

3.2.3 Radio channel(Ministerial ordinance of MIC No.162, 2011)
A radio channel shall consist of up to 5 consecutive unit channels which are defined that theircenter frequencies are located from 916.0 MHz to 916.8 MHz and from 920.6 MHz to 928.0 MHz
with 200 kHz separation and their bandwidth are 200 kHz or which are defined that theircenter frequencies are located from 928.15 MHz to 929.65 MHz with 100 kHz separation andtheir bandwidth are 100 kHz.
However, it is prohibited to simultaneously use both the unit channels giving priority toprioritized passive tag system whose center frequencies are located from 920.6 MHz to 922.2
MHz (Channel numbers are from 24 to 32) and the unit channels whose center frequencies arelocated 922.4 MHz or more (Channel numbers are 33 or more)
The center frequencies of radio channels are shown through Table 3-1 to Table 3-15.
(1) In the case of antenna power is 1mW or less(without carrier sense)
A The case of using one unit channel

Table 3-1 Center frequency of radio channel using one unit channel(Antenna power: 1 mW or less(without carrier sense), Bandwidth: 200 kHz)

Unit channel
number
1
2
3
4
5
33
34
35
36
37
38
39
40
41
42

Center frequency
(MHz)
916.0
916.2
916.4
916.6
916.8
922.4
922.6
922.8
923.0
923.2
923.4
923.6
923.8
924.0
924.2

－2-8－

Unit channel
number
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59

Center frequency
(MHz)
924.8
925.0
925.2
925.4
925.6
925.8
926.0
926.2
926.4
926.6
926.8
927.0
927.2
927.4
927.6

ARIB STD-T108
43
44

924.4
924.6

60
61

927.8
928.0

Table 3-2 Center frequency of radio channel using one unit channel(Antenna power: 1 mW or less(without carrier sense), Bandwidth: 100 kHz)

Unit channel
number
62
63
64
65
66
67
68
69

Center frequency(MHz)928.15928.25928.35928.45928.55928.65928.75928.85

Unit channel
number
70
71
72
73
74
75
76
77

Center frequency(MHz)928.95929.05929.15929.25929.35929.45929.55929.65B The case of using two unit channels
Table 3-3 Center frequency of radio channel using two unit channels(Antenna power: 1 mW or less(without carrier sense), Bandwidth: 400 kHz）

Unit channel
number
1,2
2,3
3,4
4,5
33,34
34,35
35,36
36,37
37,38
38,39
41,42
42,43
43,44
44,45
39,40
40,41

Center frequency
(MHz)
916.1
916.3
916.5
916.7
922.5
922.7
922.9
923.1
923.3
923.5
924.1
924.3
924.5
924.7
923.7
923.9

－2-9－

Unit channel
number
45,46
46,47
47,48
48,49
49,50
50,51
51,52
52,53
53,54
54,55
55,56
56,57
57,58
58,59
59,60
60,61

Center frequency
(MHz)
924.9
925.1
925.3
925.5
925.7
925.9
926.1
926.3
926.5
926.7
926.9
927.1
927.3
927.5
927.7
927.9

ARIB STD-T108
Table 3-4 Center frequency of radio channel using two unit channels(Antenna power: 1 mW or less(without carrier sense), Bandwidth: 200 kHz）

Unit channel
number
62,63
63,64
64,65
65,66
66,67
67,68
68,69
69,70

Center frequency
(MHz)
928.2
928.3
928.4
928.5
928.6
928.7
928.8
928.9

Unit channel
number
70,71
71,72
72,73
73,74
74,75
75,76
76,77

Center frequency
(MHz)
929.0
929.1
929.2
929.3
929.4
929.5
929.6

C The case of using three unit channels
Table 3-5 Center frequency of radio channel using three unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 600 kHz）

Unit channel
number
1,2,3
2,3,4
3,4,5
33,34,35
34,35,36
35,36,37
36,37,38
37,38,39
38,39,40
39,40,41
40,41,42
41,42,43
42,43,44
43,44,45
44,45,46Center frequency
(MHz)
916.2
916.4
916.6
922.6
922.8
923.0
923.2
923.4
923.6
923.8
924.0
924.2
924.4
924.6
924.8

－2-10－

Unit channel
number
45,46,47
46,47,48
47,48,49
48,49,50
49,50,51
50,51,52
51,52,53
52,53,54
53,54,55
54,55,56
55,56,57
56,57,58
57,58,59
58,59,60
59,60,61

Center frequency
(MHz)
925.0
925.2
925.4
925.6
925.8
926.0
926.2
926.4
926.6
926.8
927.0
927.2
927.4
927.6
927.8

ARIB STD-T108

Table 3-6 Center frequency of radio channel using three unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 300 kHz）

Unit channel
number62,63,64
63,64,65
64,65,66
65,66,67
66,67,68
67,68,69
68,69,70

Center frequency(MHz)928.25928.35928.45928.55928.65928.75928.85

Unit channel
number
69,70,71
70,71,72
71,72,73
72,73,74
73,74,75
74,75,76
75,76,77

Center frequency(MHz)928.95929.05929.15929.25929.35929.45929.55

D The case of using four unit channels
Table 3-7 Center frequency of radio channel using four unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 800 kHz）

Unit channel
number
1,2,3,4
2,3,4,533,34,35,36
34,35,36,37
35,36,37,38
36,37,38,39
37,38,39,40
38,39,40,41
39,40,41,42
40,41,42,43
41,42,43,44
42,43,44,45
43,44,45,46
44,45,46,47

Center frequency
(MHz)
916.3
916.5
922.7
922.9
923.1
923.3
923.5
923.7
923.9
924.1
924.3
924.5
924.7
924.9

－2-11－

Unit channel
number
45,46,47,48
46,47,48,49
47,48,49,50
48,49,50,51
49,50,51,52
50,51,52,53
51,52,53,54
52,53,54,55
53,54,55,56
54,55,56,57
55,56,57,58
56,57,58,59
57,58,59,60
58,59,60,61

Center frequency
(MHz)
925.1
925.3
925.5
925.7
925.9
926.1
926.3
926.5
926.7
926.9
927.1
927.3
927.5
927.7

ARIB STD-T108

Table 3-8 Center frequency of radio channel using four unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 400 kHz）

Unit channel
number62,63,64,65
63,64,65,66
64,65,66,67
65,66,67,68
66,67,68,69
67,68,69,70
68,69,70,71

Center frequency
(MHz)
928.3
928.4
928.5
928.6
928.7
928.8
928.9

Unit channel
number
69,70,71,72
70,71,72,73
71,72,73,74
72,73,74,75
73,74,75,76
74,75,76,77

Center frequency
(MHz)
929.0
929.1
929.2
929.3
929.4
929.5

E The case of using five unit channels
Table 3-9 Center frequency of radio channel using five unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 1000 kHz）

Unit channel number
1,2,3,4,5
33,34,35,36,37
34,35,36,37,38
35,36,37,38,39
36,37,38,39,40
37,38,39,40,41
38,39,40,41,42
39,40,41,42,43
40,41,42,43,44
41,42,43,44,45
42,43,44,45,46
43,44,45,46,47
44,45,46,47,48

Centerfrequency
(MHz)
916.4
922.8
923.0
923.2
923.4
923.6
923.8
924.0
924.2
924.4
924.6
924.8
925.0

－2-12－

Unit channel number
45,46,47,48,49
46,47,48,49,50
47,48,49,50,51
48,49,50,51,52
49,50,51,52,53
50,51,52,53,54
51,52,53,54,55
52,53,54,55,56
53,54,55,56,57
54,55,56,57,58
55,56,57,58,59
56,57,58,59,60
57,58,59,60,61

Centerfrequency
(MHz)
925.2
925.4
925.6
925.8
926.0
926.2
926.4
926.6
926.8
927.0
927.2
927.4
927.6

ARIB STD-T108

Table 3-10 Center frequency of radio channel using five unit channels(Antenna power: 1mW or less(without carrier sense), Bandwidth: 500 kHz）

Unit channel
number62,63,64,65,66
63,64,65,66,67
64,65,66,67,68
65,66,67,68,69
66,67,68,69,70
67,68,69,70,71

Center frequency(MHz)928.35928.45928.55928.65928.75928.85

Unit channel
number
68,69,70,71,72
69,70,71,72,73
70,71,72,73,74
71,72,73,74,75
72,73,74,75,76
73,74,75,76,77

Center frequency(MHz)928.95929.05929.15929.25929.35929.45(2) In the case of antenna power is 20mW or less(with carrier sense)
A The case of using one unit channel

Table 3-11 Center frequency of radio channel using one unit channel(Antenna power: 20mW or less(with carrier sense), Bandwidth: 200 kHz）

Unit channel
number
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42

Center frequency
(MHz)
920.6
920.8
921.0
921.2
921.4
921.6
921.8
922.0
922.2
922.4
922.6
922.8
923.0
923.2
923.4
923.6
923.8
924.0
924.2

－2-13－

Unit channel
number
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61

Center frequency
(MHz)
924.4
924.6
924.8
925.0
925.2
925.4
925.6
925.8
926.0
926.2
926.4
926.6
926.8
927.0
927.2
927.4
927.6
927.8
928.0

ARIB STD-T108
B The case of using two unit channels

Table 3-12 Center frequency of radio channel using two radio channels(Antenna power: 20mW or less(with carrier sense), Bandwidth: 400 kHz)

Unit channel
number
24,25
25,26
26,27
27,28
28,29
29,30
30,31
31,32
33,34
34,35
35,36
36,37
37,38
38,39
39,40
40,41
41,42
42,43

Center frequency
(MHz)
920.7
920.9
921.1
921.3
921.5
921.7
921.9
922.1
922.5
922.7
922.9
923.1
923.3
923.5
923.7
923.9
924.1
924.3

Unit channel
number
43,44
44,45
45,46
46,47
47,48
48,49
49,50
50,51
51,52
52,53
53,54
54,55
55,56
56,57
57,58
58,59
59,60
60,61

Center frequency
(MHz)
924.5
924.7
924.9
925.1
925.3
925.5
925.7
925.9
926.1
926.3
926.5
926.7
926.9
927.1
927.3
927.5
927.7
927.9

C The case of using three unit channels

Table 3-13 Center frequency of radio channel using three unit channels(Antenna power: 20mW or less(with carrier sense), Bandwidth: 600 kHz)

Unit channel
number24,25,26
25,26,27
26,27,28
27,28,29
28,29,30
29,30,31
30,31,32
33,34,35
34,35,36
35,36,37
36,37,38
37,38,39
38,39,40Center frequency
(MHz)
920.8
921.0
921.2
921.4
921.6
921.8
922.0
922.6
922.8
923.0
923.2
923.4
923.6

－2-14－

Unit channel
number43,44,45
44,45,46
45,46,47
46,47,48
47,48,49
48,49,50
49,50,51
50,51,52
51,52,53
52,53,54
53,54,55
54,55,56
55,56,57

Center frequency
(MHz)
924.6
924.8
925.0
925.2
925.4
925.6
925.8
926.0
926.2
926.4
926.6
926.8
927.0

ARIB STD-T108
39,40,41
40,41,42
41,42,43
42,43,44

923.8
924.0
924.2
924.4

56,57,58
57,58,59
58,59,60
59,60,61

927.2
927.4
927.6
927.8

D The case of using four unit channels

Table 3-14 Center frequency of radio channel using four unit channels(Antenna power: 20mW or less(with carrier sense), Bandwidth: 800 kHz)

Unit channel
number24,25,26,27
25,26,27,28
26,27,28,29
27,28,29,30
28,29,30,31
29,30,31,32
33,34,35,36
34,35,36,37
35,36,37,38
36,37,38,39
37,38,39,40
38,39,40,41
39,40,41,42
40,41,42,43
41,42,43,44
42,43,44,45

Center frequency
(MHz)
920.9
921.1
921.3
921.5
921.7
921.9
922.7
922.9
923.1
923.3
923.5
923.7
923.9
924.1
924.3
924.5

Unit channel
number43,44,45,46
44,45,46,47
45,46,47,48
46,47,48,49
47,48,49,50
48,49,50,51
49,50,51,52
50,51,52,53
51,52,53,54
52,53,54,55
53,54,55,56
54,55,56,57
55,56,57,58
56,57,58,59
57,58,59,60
58,59,60,61

Center frequency
(MHz)
924.7
924.9
925.1
925.3
925.5
925.7
925.9
926.1
926.3
926.5
926.7
926.9
927.1
927.3
927.5
927.7

E The case of using five unit channels

Table 3-15 Center frequency of radio channel using five unit channels(Antenna power: 20mW or less(with carrier sense), Bandwidth: 1000 kHz)

Unit channel
number24,25,26,27,28
25,26,27,28,29
26,27,28,29,30
27,28,29,30,31
28,29,30,31,32
33,34,35,36,37
34,35,36,37,38
35,36,37,38,39
36,37,38,39,40

Center frequency
(MHz)
921.0
921.2
921.4
921.6
921.8
922.8
923.0
923.2
923.4

－2-15－

Unit channel
number43,44,45,46,47
44,45,46,47,48
45,46,47,48,49
46,47,48,49,50
47,48,49,50,51
48,49,50,51,52
49,50,51,52,53
50,51,52,53,54
51,52,53,54,55

Center frequency
(MHz)
924.8
925.0
925.2
925.4
925.6
925.8
926.0
926.2
926.4

ARIB STD-T108
37,38,39,40,41
38,39,40,41,42
39,40,41,42,43
40,41,42,43,44
41,42,43,44,45
42,43,44,45,46

923.6
923.8
924.0
924.2
924.4
924.6

52,53,54,55,56
53,54,55,56,57
54,55,56,57,58
55,56,57,58,59
56,57,58,59,60
57,58,59,60,61

926.6
926.8
927.0
927.2
927.4
927.6

(ORE: article 5, attached table No.1)

3.2.4 Frequency tolerance(NT: No.50, 1988)(Revised NT: No.533, 2011)
It shall be within 20 x 10-6.
However, above rule may not apply in case of using a single unit channel where the bandwidthof the unit channel shall be the bandwidth of the designated frequency band. ("Designatedfrequency band" means that the frequency at the center of the frequency band coincides with theallocated frequency band and the frequency bandwidth is equal to the sum of the acceptance ofoccupied frequency band width and twice the absolute value of the permissible deviation of thefrequency.)

3.2.5 Modulation method
It shall not be specified.

3.2.6 Permissible Value for Occupied Bandwidth(ORE: article 6, attached table No.2)(NT: No.659, 2006)(Revised NT: No.535, 2011)

It shall be (200 x n) kHz or less. However, in the case that the center frequency is from 928.15
MHz to 929.65 MHz, it shall be (100 x n) kHz or less. (n is a number of unit channels
constituting the radio channel and is an integer from 1 to 5.)－2-16－

ARIB STD-T108(ORE: article 49-14)

3.2.7 Adjacent channel leakage power(Ministerial ordinance of MIC No.162, 2011)(1) Frequency band of signal in use is from 915.9MHz to 916.9MHz(Antenna power is 1mWor less(without carrier sense))i)Spectral power at the edge of a radio channel: It shall be –20dBm or less.

ii)

Leakage power in unit channel adjacent to a radio channel: It shall be –26dBm or
less.

Unit : dBm / 100kHz
200kHz (200×n)kHzPower at the edge:–20dBm or less

200kHz0-10-20
Spurious emission strength(915MHz to 930MHz):－36dBm／100ｋHz

-30
-40
Unit:
kHz

-50
Adjacent channel
leakage power :–26dBm or less

Lower adjacentunit channel

fc(Center frequency)

fc－200－100×(n－1)

Upper adjacentunit channel

fc＋200＋100×(n－1)（Note: Center frequency is one of frequencies shown in Table 3.1, Table 3.3, Table
3.5, Table 3.7 and Table 3.9 of 3.2.3 Radio channel and n is a number ofunit radio channels constructing a radio channel.)Figure 3-1 Channel mask of a radio channel whose frequency is from 915.9MHz to916.9MHz(Antenna power is 1mW or less(without carrier sense)).

－2-17－

ARIB STD-T108(2) Frequency band of signal in use is from 920.5MHz to 922.3MHz(Antenna power
is 20mW or less(with carrier sense))i)Spectral power at the edge of a radio channel: It shall be –7dBm or less.

ii)

Leakage power in unit channel adjacent to a radio channel: It shall be –15dBm or
less. If antenna power is reduced by 1mW or less, each adjacent channel leakage
power is -26dBm or less.

Unit : dBm / 100kHz
Power at the edge:–7dBm or less

200kHz(200×n)kHz

200kHz20
10

Spurious emission
strength(920.3MHz to 924.3MHz):–36dBm / 100kHz

0
-10
-20
-30
-40

Unit
kHz

-50

Adjacent channel
leakage power :fc
Lower adjacentUpper adjacent–15dBm or less(Centerfrequency)(中心周波数)unit
channelunit channel(If the case of 1mW orless, -26dBm or less)fc－200－100×(n－1)
fc＋200＋100×(n－1)（Note: Center frequency is one of frequencies shown in Table 3.11 to Table 3.15 of
3.2.3 Radio channel and n is a number of unit radio channels constructing aradio channel.)Figure 3-2 Channel mask of a radio channel whose frequency is from 920.5MHz to922.3MHz(Antenna power is 20mW or less(with carrier sense)).

－2-18－

ARIB STD-T108(3) Frequency band of signal in use is from 922.3MHz to 928.1MHz. (Antenna power is 1mWor less(without carrier sense).)i)

Leakage power in unit channel adjacent to a radio channel: It shall be –26dBm or
less.
Unit: dBm / 100kHz(200×n)kHz

200kHz200kHz0-10
Spurious emission
strength(915MHz to 930MHz):–36dBm / 100kHz

-20
-30
-40
Unit
kHz

-50
Adjacent channel
leakage power :–26dBm or less

Lower adjacentunit channel

fc(Center frequency)

fc－100×n

Upper adjacentunit channel

fc＋100×n（Note: Center frequency is one of frequencies shown in Table 3.1, Table 3.3, Table
3.5, Table 3.7 and Table 3.9 of 3.2.3 Radio channel and n is a number ofunit radio channels constructing a radio channel.)Figure 3-3 Channel mask of a radio channel whose frequency is from 922.3MHz and to928.1MHz (Antenna power is 1mW or less(without carrier sense)).

－2-19－

ARIB STD-T108(4) Frequency band of signal in use is from 922.3MHz to 928.1MHz. (Antenna power is
20mW or less(with carrier sense).)i)

Leakage power in unit channel adjacent to a radio channel: It shall be –15dBm or
less.

Unit: dBm / 100kHz(200×n)kHz

200kHz200kHz20
100
Spurious emission
strength(915MHz to 930MHz):–36dBm / 100kHz

-10
-20
-30
-40

Unit:
kHz

-50
Adjacent channel
leakage power :–15dBm or less

Lower adjacentunit channel

fc－100×nfc(中心周波数)(Centerfrequency)

Upper adjacentunit channel

fc＋100×n（Note: Center frequency is one of frequencies shown in Table 3.11 to Table 3.15 of
3.2.3 Radio channel and n is a number of unit radio channels constructing aradio channel.)Figure 3-4 Channel mask of a radio channel whose frequency is from 922.3MHz to 928.1MHz(Antenna power is 20mW or less(with carrier sense).)－2-20－

ARIB STD-T108(5) Frequency band of signal in use is from 928.1MHz to 929.7MHz. (Antenna power is 1mWor less(without carrier sense).)i)

Leakage power in unit channel adjacent to a radio channel: It shall be –26dBm or
less.
Unit: dBm / 100kHz(100×n)kHz

100kHz

100kHz0-10
Spurious emission
strength(915MHz to 930MHz):–36dBm / 100kHz

-20
-30
-40
Unit
kHz

-50
Adjacent channel
leakage power :–26dBm or less

Lower adjacentunit channel

fc(Center frequency)

fc－50×nUpper adjacentunit channel

fc＋50×n（Note: Center frequency is one of frequencies shown in Table 3.2, Table 3.4, Table
3.6, Table 3.8 and Table 3.10 of 3.2.3 Radio channel and n is a number ofunit radio channels constructing a radio channel.)Figure 3-5 Channel mask of a radio channel whose frequency is from 928.1MHz to929.7MHz(Antenna power is 1mW or less(without carrier sense))－2-21－

ARIB STD-T108

3.2.8 Permissible Values for Spurious Emission / Unwanted Emission Intensity(ORE: article 7, Attached table No.3-25)(Ministerial ordinance of MIC No.162, 2011)
Permissible Values for Spurious Emission / Unwanted Emission Intensity at the antenna input
shall be less than the value in Table 3-16.

Table 3-16 Permissible Values for Spurious Emission / Unwanted Emission Intensity (Antenna input)

Spurious emission /Unwanted Emission
Intensity (average power)－36 dBm

Frequency bandf <= 710 MHz

Reference
bandwidth
100 kHz－55 dBm

1M Hz－55 dBm

100 kHz－36 dBm

100 kHz－55 dBm

100 kHz

1000MHz < f <= 1,215 MHz－45 dBm

1M Hz

1,215 MHz < f－30 dBm

1M Hz

710 MHz < f <= 900 MHz
900 MHz < f <= 915 MHz
915 MHz < f <= 930 MHz(Except for |f-fc| <= (200+100×n) kHz
if bandwidth of unit channel is 200 kHz,except for |f-fc| <= (100+50×n) kHz if
bandwidth of unit channel is 100 kHz.
Except for |f-fc| <= (100+100×n)kHz if
frequency band is 915.9MHz <= f <=916.9MHz and 920.5MHz <= 922.3MHz.
Where n is a number of unit channels
constituting the radio channel and is an
integer from 1 to 5)
930 MHz < f <= 1000 MHz－2-22－

ARIB STD-T108

3.3 Receiver
Limit on Secondary Radiated Emissions, etc.

(ORE: article 24-16)(Ministerial ordinance of MIC No.162, 2011)

Limit on Secondary Radiated Emissions shall be value in Table 3-17 or less.

Table 3-17 Limit on Secondary Radiated Emissions

Frequency bandf <= 710 MHz

Limit on Secondary
Radiated Emissions(Antenna input)－54 dBm

Reference
bandwidth
100 kHz

710 MHz < f <= 900 MHz－55 dBm

1 MHz

900 MHz < f <= 915 MHz－55 dBm

100 kHz915 MHz < f <= 930 MHz－54 dBm

100 kHz930 MHz < f <= 1000 MHz－55 dBm

100 kHz

1000 MHz < f－47 dBm

1 MHz

3.4 Controller
Controller shall have the functions that comply with the conditions specified in this section
described below.
(ORE: article 49-14, NT: No.49, 1989)

3.4.1 Transmission time control equipment(Revised NT: No.531, 2011)(1) In case the 5ms or more carrier sense is required:If the center frequency is from 920.6MHz to 922.2MHz, or if the center frequency is from922.4MHz to 923.4MHz, radio equipment shall stop its transmission of radio wave less than4s after it starts to emit radio wave. It shall wait 50ms or more for the consecutive
transmission.
Meanwhile, it may emit radio wave again without waiting 50ms, if the transmission time isless than 4s after its first transmission, and this re-transmission is started after 128µs or
more carrier sense, and is finished less than 4s after its first transmission.
(2) In case the 128µs or more and less than 5ms carrier sense time is required:If the center frequency is from 922.4MHz to 928.0MHz, the following conditions shall besatisfied.
1. Using one unit channel: radio equipment shall stop its transmission of radio wave less－2-23－

ARIB STD-T108
than 400ms after it starts to emit radio wave. The sum of transmission time per arbitrary one
hour shall be 360s or less.
Meanwhile, if the transmission time is more than 6ms and is 200ms or less, it shall wait for
2ms for the consecutive transmission. If the transmission time is more than 200ms, it shallwait for ten times or more of the former transmission time. When a transmission using
different center frequency is used after the previous transmission is completed, transmission
in a different frequency channel is allowed after 2ms of the completion of transmission in theformer channel without waiting for ten times or more of the former transmission time.
2. Using two unit channels: radio equipment shall stop its transmission of radio wave lessthan 200ms after it starts to emit radio wave. The sum of transmission time per arbitrary one
hour shall be 360s or less. Meanwhile if the transmission time is more than 3ms, it shall wait
for 2ms for the consecutive transmission.
3. Using 3, 4, or 5 unit channels: radio equipment shall stop its transmission of radio wave
less than 100ms after it starts to emit radio wave. The sum of transmission time per
arbitrary one hour shall be 360s or less. Meanwhile if the transmission time is more than2ms, it shall wait 2ms for the consecutive transmission.
(3) In case non carrier sense is required:
The following conditions shall be satisfied.
1. If the center frequency is from 916.0MHz to 916.8MHz, or from 922.4MHz to 928.0MHz,
and the antenna power is 1mW or less, radio equipment shall stop its transmission of radio
wave less than 100ms after it starts to emit radio wave. It shall wait 100ms or more for theconsecutive transmission. The sum of transmission time per arbitrary one hour shall be 3.6s
or less.
Meanwhile, it may emit radio wave again without waiting 100ms, if the transmission timeless than 100ms after its first transmission
2. If the center frequency is from 928.15MHz to 929.65MHz, radio equipment shall stop its
transmission of radio wave less than 50ms after it starts to emit radio wave. It shall wait
50ms or more for the consecutive transmission.
Meanwhile, it may emit radio wave again without waiting 50ms, if the transmission time isless than 50ms after its first transmission and the re-transmission is finished less than 50ms
after its first transmission.

－2-24－

ARIB STD-T108(ORE: article 49-14, NT: No.49, 1988)

3.4.2 Carrier sense(Revised NT: No.531, 2011)(1) Radio equipment shall check if the interference exists by the career sense procedure
before its new transmission.
(2) Carrier sense time shall be 128µs or more.
(3) Carrier sense level, amount of received power at all of unit channels included in theradio channel to emit, shall be -80dBm at the antenna input. When the carrier senselevel is more than -80dBm, radio equipment shall not emit any radio wave. However, incase were transmission power exceeds 20mW, the carrier sense level shall be further
deduced from -80dBm by the exceeding power above 20mW.
(4) Carrier sense is not necessary if the antenna power is 1mW or less and the conditions of
3.4.1 (3) are satisfied(ORE: article 49-14, NT: No.49, 1989)

3.4.3 Skipping carrier sense in a response(Revised NT: No.531, 2011)
If the transmission is a response to request by other radio equipment, and following conditions
are satisfied, carrier sense is not necessary, and the response time is not included in the sum oftransmission time per arbitrary one hour.
1. Using one unit channel: the transmission starts within 2ms after the reception of therequest is completed, and the transmission ends within 50ms after the reception of the request
is completed.
2. Using 2, 3, 4, or 5 unit channels: the transmission starts within 2ms after the reception of
the request is completed, and the transmission ends within 5ms after the reception of therequest is completed.
Figure 3-6 shows concept of a response that does not require carrier sense.

－2-25－

ARIB STD-T108

Carrier sense
Station A

Data transfer(Note1)

Response completion time
Station B
Response(Note2)

Response start time
Figure 3-6 Concept of a response that does not require carrier sense(Note1) In Station A, measurement of pause duration shall start at completion oftransmission at Station A.
(Note2) In Station B, measurement of pause duration shall start at completion of responseat Station B.

－2-26－

ARIB STD-T108

Table 3-18 shows possible combinations of sending control parameters specified by 3.4.1
Sending control, 3.4.2 Carrier sense and 3.4.3 Skipping carrier sense in a response.

Table 3-18 Possible combinations of sending control parameters specified by 3.4.1 Sending control, 3.4.2
Carrier sense and 3.4.3 Skipping carrier sense in a response

Antennapower(Note5)

1mW or less

Unit CH
bandwidth

CH usedCarrier
in asense timebundleSending
duration

1-5
33-61

200kHz1～5ch

100ms orless(Note2)

100ms

62-77

100kHz50ms orless(Note3)

24-38

None

200kHz

1～5ch
1～5ch

5ms or
more

33-61

128μs
or more200kHz2ch

3～5ch

Conditions of response to
skip carrier sense (Note 4)
Completiontime

Start time

3.6sec or
less

―

―

50ms

None

―

―

4s(Note1)

50ms

None

―

―

More than
200ms, and400ms or less

Ten times ormore of theformertransmission
time or2ms (Note6)1chMore than
1mW andless than orequal to20mW

The sum oftransmission
time perPause duration
arbitrary one
hour

AppliedCH
numberMore than
6ms, and200ms or less
6ms or lessMore than
3ms, and200ms or less
3ms or lessMore than2ms, and
100ms or less
2ms or less

50ms or less

2ms
None

360sec or
less

2ms or less

2ms
None

5ms or less

2ms
None

(Note1) It may emit again without waiting 50ms, if it is within 4s after its first transmission.
The transmission shall start after carrier sense is performed for 128µs or more and thetransmission shall finish within this 4s interval.
(Note2) It may emit again without waiting 100ms, if it is within 100ms after its firsttransmission and the transmission is finished within this 100ms interval.
(Note3) It may emit again without waiting 50ms, if it is within 50ms after its firsttransmission and the transmission is finished within this 50ms interval.
(Note4) Transmission time of a response that satisfies the conditions is not included in thesum of transmission time per arbitrary one hour.
(Note5) 250mW or less is allowed given the radio equipment housed in a single cabinet andshall not be opened easily, and its EIRP (Note) is 16dBm or 3dBm or less (value when
applying 20mW or 1mW of antenna power to the transmitting antenna having absolute
gain of 3dBi). Here, EIRP is the value when antenna power is applied to the antenna
gain and it includes the deviation of the antenna power.

－2-27－

ARIB STD-T108(Note6) When a transmission using different center frequency is used after the previoustransmission is completed, transmission in a different frequency channel is allowed after
2ms of the completion of transmission in the former channel without waiting for ten
times or more of the former transmission time.
(RL: article 4-3, RERL: article 6-2)

3.4.4 Interference prevention function

The radio equipment shall automatically transmit/receive identification codes.
(ORE: article 49-14)

3.5 Cabinet(Ministerial ordinance of MIC No.66, 2008)
The high frequency circuit and modulation modules except for antenna shall be structured not
to be opened easily.

3.6 Connection to telecommunication circuit(OCTF: article 9, NT: No.424, 1994)
Radio equipment shall satisfy the following conditions.
(1) It shall have identification code which shall be 32 bits length or more.
(2) Except for particular case which is defined outside of the specification, it shall makedecision if channel is used or not before using that channel. Only if that decision is "channel
is not used", it can set a communication path on its channel.
(ORE: article 49-14)

3.7 Antenna(Ministerial ordinance of MIC No.66, 2008)
Antenna gain

3dBi or less (absolute gain)
However, in case EIRP is more than 16dBm or 3dBm (value when
applying the antenna power set forth in 3.2(1) to the transmitting
antenna having absolute gain of 3dBi), the excess amount should be
reduced by the antenna gain, and if it is 16dBm or 3dBm or less, it isallowed to fill in the gap by the antenna gain. Here, EIRP is the value
when antenna power is applied to the antenna gain and it includes thedeviation of the antenna power.

－2-28－

ARIB STD-T108

Chapter 4 Measurement

methods

TELEC-T245, which is established based on Notification No. 88-2 of MIC by Telecom
Engineering Center, shall be applied. If the other method is specified by Notification of MIC orothers, it shall be also applied.

－2-29－

ARIB STD-T108

Appendix

Operational rule

ARIB STD-T108

Contents
1 Overview.................................................................................................................................... 1
1.1 Purpose ............................................................................................................................... 1
1.2 Scope of Application ........................................................................................................... 1
1.3 Target Systems .................................................................................................................. 1
2 Interference Avoidance Method............................................................................................... 1
2.1 Channel Assignment ......................................................................................................... 1
2.1.1 915.9 MHz to 916.9 MHz ............................................................................................ 1
2.1.2 920.5 MHz to 922.3 MHz ............................................................................................ 1
2.1.3 922.3 MHz to 929.7 MHz ............................................................................................ 2
2.2 Interference to aeronautical radio systems ..................................................................... 2
2.3 Coexistence to systems using different carrier sense times ........................................... 2
2.4 Recommended operating Practice for 250mW category stations ................................... 3
2.4.1 Interference mitigation ............................................................................................... 3
2.4.2 Interconnection with specified low-power radio stations ......................................... 4
2.5 Implementing functionality of frequency channel switch............................................... 4
3 Influence to medical equipment .............................................................................................. 4
4 Protection of privacy ................................................................................................................. 45 Radio equipment operates under multiple provisions ........................................................... 5
5.1 Type of provision ................................................................................................................ 5
5.2 Radio equipment specified in this chapter ....................................................................... 5
5.3 Operation of the equipment .............................................................................................. 5
5.3.1 The principle of operation ........................................................................................... 5
5.3.2 Clear indication of operation of equipment ............................................................... 6
5.3.3 The example of operating equipment ........................................................................ 6
5.3.4 Equipment operated by changing conditions under the same provision ................ 7
6 Changes on revision up ............................................................................................................ 8
6.1 Updates from ARIB STD-T96 to ARIB STD-T108 v1.0 .................................................. 8
6.1.1 Improvement of usability for active tag system........................................................ 8
6.1.2 Sharing with passive tag systems .............................................................................. 8
6.1.3 Antenna power ............................................................................................................ 9
6.2 Updates from ARIB STD-T108 v1.0 to ARIB STD-T108 v1.1 ...................................... 10
6.2.1 Use of narrow band frequency.................................................................................. 10
6.2.2 Revise of 1mW and 20mW stations ......................................................................... 10－3-i－

ARIB STD-T108

6.2.3 Adoption of EIRP method ......................................................................................... 11
6.3 Updates from ARIB STD-T108 v1.1 to ARIB STD-T108 v1.2 ...................................... 13
7 Channel plan for 920MHz-band radio equipment ............................................................... 15－3-ii－

ARIB STD-T108

Appendix

Operational rule

1 Overview
1.1 Purpose
These guidelines aim to avoid undesired interference to other neighboring wireless systems,
to effectively utilize frequency resource and to guarantee user’s convenience when a user
operates 920 MHz-band convenience radio stations or specified low-power radio stations fortelemeter, telecontrol and data transmission (these are abbreviated to “convenience radio
stations” and “specified low-power radio stations” respectively in the following sentences).

1.2 Scope of Application
These guidelines are directed to users, manufacturers, sellers, constructors, operators andmaintenance persons.

1.3 Target Systems
These guidelines target following systems: 920 MHz-band telemeter, telecontrol and datatransmission radio equipment (ARIB STD-T108).

2 Interference Avoidance Method
2.1 Channel Assignment
Radio stations targeted in this standard shares 920 MHz-band with STD-T106(920MHz-band RFID equipment for premises radio station) or STD-T107 (920MHz-band RFID
equipment for specified low power radio station) radio stations. In an effort to avoid
interference with those radio stations, this standard specifies the following channel
assignment.

2.1.1 915.9 MHz to 916.9 MHz
Internationally circulating radio stations with its antenna power 1 mW or less shallexclusively use this band.

2.1.2 920.5 MHz to 922.3 MHz
As is described in Part I 3.4.1-(1) and Part II 3.4.1-(1), radio stations shall conform to thetechnical rules specified in STD-T106 (high power passive tag readers) and STD-T107 (lowpower passive tag readers), and in addition, shall conduct carrier sense for 128 µs or more

－3-1－

ARIB STD-T108

before retransmission even if that retransmission is within 4 s after having completed carrier
sense for not less than 5ms. If a radio station uses a portion of this band as part of the bundledunit channels, it shall also conform to the rules specified above.

2.1.3 922.3 MHz to 929.7 MHz
Radio stations must conform to the rules specified in Part I 3.4.1-(2) and Part II 3.4.1-(2) ofthis standard.

2.2 Interference to aeronautical radio systems
Electronic equipment that is prohibited from being activated on aircraft to maintain the safetyof aircraft pursuant to the provisions of Civil Aeronautics Act which falls under the radio
stations specified in this standard shall have either of the following structures if it is to be
carried on aircraft:•

The equipment shall be deactivated by removing the batteries or being switched off•

The equipment shall have a structure such that it cannot be activated without being
switched on.

However, it is not necessary for radio equipment assessed using the test procedures describedin DO-294 published by the RTCA and confirmed to be free from the risk of interference to havethe above-mentioned structures.
Related laws and regulations•

Civil Aeronautics Act Article 73-4•

Ordinance for Enforcement of the Civil Aeronautics Act Article 164-15 Safety
impending acts•

Notification No. 1346 of Ministry of Land, Infrastructure, Transport and Tourism(2003): Devices prohibited for use at all times

2.3 Coexistence to systems using different carrier sense times
As specified in this standard, there are two types of radio stations in the 920MHz- band;
short CS stations using carrier sense time of 128 µs or more and long CS stations using carrier
sense time of 5ms or more. Short CS stations are efficient to have low power consumption withbatteries, by means of short data communication with long duration. In this standard, totaltransmission time of short CS stations shall be 10% or less of duration.
However, as shown in Fig. S-1, there is a possibility that short CS stations within aninterference range, in which they affect their carrier senses each other, periodically repeat data

－3-2－

ARIB STD-T108

transmissions and occupy a channel more than long CS stations. In order to remove thepossibility, it is preferable for a system, in which multiple radio stations transmit data
periodically and affect their carrier sense with each other, to be designed or operated to havecontinuous margin time of 5ms or more.

Long CS stations

Carrier busy detection

Carrier busy detection

Carrier sense

Carrier busy detection

T : System duration

Short CS stations

S : Continuous transmission time
Fig. S-1 Time sequence diagram for a case in which short CS stations within an interference
range periodically repeat data transmissions and occupy a channel more than long CS stations.
For example, in the case of Fig. S-1, it is preferable for a system to be designed or operated tosatisfy
T > (N * S) + 5ms, where T is system duration, N is the number of radio stations which affect their carrier sensewith each other and S is averaged continuous transmission time per one radio station.

2.4 Recommended operating Practice for 250mW category stations
2.4.1 Interference mitigation
In order to minimize the possible interference, it is strongly recommended especially for
250mW category stations to operate under its requisite minimum transmission power. To－3-3－

ARIB STD-T108

this end, using a directional antenna to ensure the sufficient emission strength with
reduced transmission power is a typical preferred practice, in which less transmission
power than allowable maximum value is compensated by antenna gain. In the place where
each system sharing same frequency band is operating in close proximity or within limitedarea, introducing an electromagnetic shield to avoid the mutual interference is alsofavorable as well.
2.4.2 Interconnection with specified low-power radio stations
Land

mobilestations

andspecified

low-powerradio

stationsaremutuallyinterconnected.
2.5 Implementing functionality of frequency channel switch
In case that any possible interference is anticipated between the systems sharing same
frequency band, or in place where any frequent interference tends to happen on a specificfrequency channel, it is recommended for all category of stations except for 1mW or lesscategory to implement the channel switch function in automatic manner or even by manualmeans, so as to select and utilize other channels.

3 Influence to medical equipment
To avoid the influence to medical equipment, it is desirable to act properly according to theguideline of action described in “Study Report on the Effect of Radio Waves on Medical
Devices”(Note1).
(Note1): When issuing version 1.0 of this standard (February 14th, 2012), it indicates thereport issued by MIC on March, 2007. However, when it is revised, it indicates the latest
version.

4 Protection of privacy
For protection of privacy, it is desirable to act properly according to “Guidelines for Privacy
Protection with Regard to RFID Tags”(Note2).
(Note2): When issuing version 1.0 of this standard (February 14th, 2012), it indicates theguideline issued by MIC and METI on 8th June, 2004. However, when it is revised, it
indicates the latest version.

－3-4－

ARIB STD-T108

5 Radio equipment operates under multiple provisions
The provisions of technical requirements which radio equipment shall follow differs according
to its technical conditions such as antenna power and/or frequency channels to use. In thischapter, priorities and correlation among provisions are defined clearly to avoid complicatedprocedures on certification.
5.1 Type of provision
In this chapter, the "type of provision" means the combination of each parameter which is
specified as "3.4.1 Sending duration" and "3.4.2 Carrier sense time" which were shown in Table
3-8 in part 1 and Table 3-18 in part 2.

5.2 Radio equipment specified in this chapter
In this chapter, the radio equipment operates under multiple provisions means equipment
which Technical Regulations Conformity Certification is granted for more than one type ofprovisions, and other condition is as described below:(1) A radio equipment whose type of provision is designed to be specified upon its shipment
or installation.
(2) A radio equipment whose type of provision is designed to be switched according to thedirections from external.
(3) A radio equipment whose type of provision is designed to be switched according to thedirections from the other communication equipment or autonomously.

5.3 Operation of the equipment
5.3.1 The principle of operation
Radio equipment is required to be designed to operate according to the following
principles.
(1) Never transmit multiple signals simultaneously, except only the case of transmitting
signal using multiple consecutive unit radio channels as specified in this standard.
(2) In transmission operation, the series of operation from the carrier sense to the pause
shall be performed in accordance with same type of provision.
(3) Regardless of the provision under which the transmission operation performed, theamount of sending time shall be determined as the amount of all transmitted durationfrom 3600 seconds before starting transmission. However, for the transmission using thechannel whose center frequency is 928MHz or below, the transmitted duration using only

－3-5－

ARIB STD-T108

the channels whose center frequency is over 928.15MHz is not required to beaccumulated.

5.3.2 Clear indication of operation of equipment
When you apply for obtaining Technical Regulations Conformity Certification of equipment
which operates under multiple provisions, following parameters shall be clearly indicated.
(1) In changing a transmitting channel by the channel consist only of unit channels whose
center frequency is 928MHz or less and the channel consist only of unit channels whose
center frequency is 928.15MHz or more, its sending duration, pause duration, theamount of sending time summed for 1 hour, carrier sense level and carrier sense time foreach frequency range.
(2) In changing antenna power by 1mW or less and more than 1mW and 20mW or less, itssending duration, pause duration, the amount of sending time summed for 1 hour,carrier sense level and carrier sense time for each power range.
(3) In changing a carrier sense time by 5ms or more, and, 128us or more and less than 5ms,
its frequency range, sending duration, pause duration and the amount of sending timesummed for 1 hour for each carrier sense time. Preferably, annotate that the amount ofsending time is accumulated across all the sending time regardless of carrier sense time,or annotate that the amount of sending time summed for 1 hour never exceeds specified
value by equipment configuration.

5.3.3 The example of operating equipment(1) The example of transmitting channel No.50 and No.70 by turns
Radio equipment is operated by following procedures.
a) Radio equipment checks that the total transmitting time for the past 3600s in
the unit channel No.1 to No.61 is 359.6s or less.
b) Radio equipment checks not giving interference to other system in the channel
No.50 (200kHz bandwidth) by carrier sense 128us or more.
c) Radio equipment transmits channel No.50 (200kHz bandwidth) in 400ms.
d) Radio equipment waits for 4s.
e) Radio equipment transmits channel No.70(100kHz bandwidth) in 50ms.
f) Radio equipment waits for 50ms.

－3-6－

ARIB STD-T108(2) The example of transmitting with 5ms carrier sense and 128us carrier sense by turns.
Radio equipment is operated by following procedures.
a) Radio equipment checks not giving interference to other system in the channel
No.32 by carrier sense 5ms or more.
b) Radio equipment transmits channel No.32 in 4s.
c) Radio equipment checks that the total transmitting time for the past 3600s in theunit channel No.1 to No.61 is 359.6s or less.
d) Radio equipment checks not giving interference to other system in the channel
No.33 by carrier sense more than 128us.
e) Radio equipment transmits channel No.33 in 400ms.
f) Radio equipment waits for 4s.
5.3.4 Equipment operated by changing conditions under the same provision
Equipment is allowed to operate changing its operating condition such as frequency andconsecutive unit channels to use, following the single provision of carrier sense and sending
duration. In this case, the operating condition shall not be changed during the transmission
and until the following response signal for which the carrier sense is exempted according to“3.4.3 Skipping carrier sense in a response” is received.

Also, in the case of retransmission

without pause period according to “3.4.1 Transmission time control equipment”, the operating
condition shall not be changed on retransmission.
Some permissible examples are shown as follows.
(1) Example of changing frequencies underthe same provisiona) Equipment executes carrier sense for 128µs or more on unit channels No.33 and 34, so
confirms no possible interference.
b) Equipment transmits for up to 200ms on unit channels No.33 and 34.
c) Equipment receives a response signal which is returned within 5ms from thedestination on unit channels No.33 and 34.
d) Taking a certain transmission pause period, then, equipment executes carrier sense
for 128µs or more on unit channels No. 35 and 36, so confirms no possible interference.
e) Equipment transmits for up to 200ms on unit channels No.35 and 36.
f) Equipment receives a response signal which is returned within 5ms from thedestination on unit channels No. 35 and 36.
(2) Example of changing the number of consecutive channels under the same provisiona) Equipment executes carrier sense for 128µs or more on unit channels No.33, 34 and－3-7－

ARIB STD-T108

35 and confirms no possible interference.
b) Equipment transmits for up to 100ms on unit channels No.33, 34 and 35.
c) Taking a certain transmission pause period, then, equipment executes carrier sense
for 128µs or more on unit channels No. 33, 34 ,35, 36 and 37, so confirms no possible
interference.
d) Equipment transmits for up to 100ms on unit channels No. 33, 34 ,35, 36 and 37.

6 Changes on revision up

6.1 Updates from ARIB STD-T96 to ARIB STD-T108 v1.0
This standard has been newly established, following the amendment notification of RadioLaw on December 14, 2011. This standard is based on ARIB STD-T96, “950 MHz-Band
Telemeter, Telecontrol and Data Transmission Radio Equipment for Specified Low PowerRadio Station,” the version 1.0 of which was established on June 6, 2008 and revised to theversion 1.1 on July 15, 2010.
The deliberation for the amendment of Radio Law and the creation of this standard were
undertaken to suffice following requirements.
6.1.1 Improvement of usability for active tag system
Except for the channels shared with passive tag systems, the carrier sense time should be
unified to 128μs and the pause duration after each transmission should be set to short timesuch as 2 ms to improve fairness of frame transmission.
To avoid channel monopolization by a particular system, the maximum frame size should be
set to requisite minimum and carrier sense should be invoked before each transmission.
Except for the channels shared with passive tag systems, the percentage of the transmission
time should be restricted to 10 % to improve shared use of a single channel by multi systems.
By dropping down the transmission power, no carrier sense should be allowed forinexpensive systems without receiver circuit such as a remote controller or a tag system.
6.1.2 Sharing with passive tag systems
For the channels shared with passive tag systems, carrier sense time and sending control
should be set in consideration of the condition of passive tag systems same as before.

－3-8－

ARIB STD-T108

6.1.3 Antenna power
950MHz active tag systems are specified as specified low-power radio stations. Its maximum
antenna power is 10 mW. This transmission power is sufficient for a certain amount ofapplication systems but is not sufficient for particular application systems.
For example, there are communication systems between towers of an electrical power line,
monitoring systems of a structural object such as a bridge, tunnel or highway and observation
systems of environment of mountain area, human behavior or the ecology of wild animals. For
many sensor systems in outdoor, a few hundreds mW of transmission power is necessary toachieve a long distance and stable transmission against the influence of shielding by landscapeand structural objects. Smart meters or water meters are essential to have a small built-in
antenna and are located in poor propagation environment such as inside a pipe shaft or under
the ground. So, they get a lot of propagation loss. To compensate these propagation losses,
about a few tens or a few hundreds mW of transmission power should be allowable.
In USA or Europe, allowable transmission power is higher than that in Japan. In USA, 1 W
of maximum transmission power is specified in FCC. In Europe, 25 mW (ERP) of transmission
power for SRD (Short Range Device) in 915MHz band is discussed in ETSI. For international
cooperation, these specifications of transmission power need to be considered for Japanese 920
MHz regulation.
In consideration of above condition, the following is specified for active tag systems.
For long transmission in suburban environment, 250 mW of antenna power which has been
specified for passive tag systems is also applied for active tag systems. However, to avoid
interference to LTE, MCA and other low power systems, available channels get to be limited.
In consideration of 25 mW (ERP) of transmission power being discussed in ETSI, antenna
power is increased to 20 mW from 10 mW assuming 3dBi antenna.
In consideration of international cooperation, channels of 1 mW antenna power are specifiedin part of 915 MHz – 921 MHz which is common frequency band with USA and Europe and 928
MHz – 930 MHz which is guard band with MCA.

－3-9－

ARIB STD-T108
6.2 Updates from ARIB STD-T108 v1.0 to ARIB STD-T108 v1.1
This standard has been revised to v1.1 following the amendment notification of Radio Law on
September 11th, 2017.
During the discussions for the amendment of Radio Law and for this standard, the following
requirements are considered.
6.2.1 Use of narrow band frequency
Radio Law and ARIB STD-T108 specify a unit channel as 100kHz/200kHz and the tolerance
from center frequency as 20ppm or less, however, some specifications such as LPWA enhance
the frequency utilization efficiency by using extremely narrow band around 100Hz.
In order to make use of such narrow band frequencies, it is deregulated to apply designatedfrequency band with condition of using unit channel of 100kHz/200kHz.
To avoid interference with existing radio stations which use single unit channel orconsecutive multiple unit channels, a radio station using narrow band frequency shall execute a
carrier sense across a unit channel of 100kHz/200kHz width.

Figure S-2 Adoption of designated frequency band
(Quoted from a report at Land Mobile Division, Telecommunication Bureau, MIC)

6.2.2 Revise of 1mW and 20mW stations
Radio Law and ARIB STD-T108 v1.0 specified 20mW station as “a station with over 1mW
and less than or equal to 20mW power” which prevents equipment with 1mW or less power fromusing the technical conditions for 20mW stations below;
1)

Basic condition of active tag: 128µs-CS, 400ms-transmission, 2ms-pause, transmit total

time 360s per 1 hour.
2)

Condition to share with passive tag: 5ms-CS, 4s-transmission, 50ms-pause－3-10－

ARIB STD-T108

In order for a station with 1mW or less power to use the above-mentioned technicalconditions, the lower limitation for 20mW station is removed.

As this may lead to

duplicated provisions regarding the former 1mW station, ARIB STD-T108 clarifies them byusing following categories;“1mW or less (with no carrier sense)” : the former “1mW or less”

“20mW or less (with carrier sense)” : the former “over 1mW and less than or equal to20mW” and old “1mW or less” with conditions 1) and 2) above.
However, as for a radio channel mask for equipment with 1mW or less power, in case that a
carrier sense is required, the radio channel mask for equipment with 20mW or less power isapplied.
6.2.3 Adoption of EIRP method
Radio Law and ARIB STD-T108 specify antenna power of radio equipment and antenna gain
respectively. However, it has been allowed to compensate for the loss by increasing antenna
gain if the antenna power is lower than the limit.
In this revision, it is mitigated that the loss of poor antenna gain can be compensated for byincreasing the antenna power as Figure S-3 depicts.

Figure S-3 Adoption of EIRP method(Quoted from a report at Land Mobile Division, Telecommunication Bureau, MIC)

－3-11－

ARIB STD-T108[EIRP conditions]
20mW or less: Equivalent isotropic radiated power (antenna power + antenna gain) ≤16dBm
1mW or less:Equivalent isotropic radiated power (antenna power + antenna gain) ≤3dBm
where an equivalent isotropic radiated power is a sum of transmit antenna gain andantenna power and it includes the tolerance of antenna power.
[Condition to use / Notes]
Antenna shall be integrated with radio equipment.

Therefore, EIRP provision is notapplicable to equipment which uses external/removal antennas.
Maximum antenna power is 250mW.



In a test like Technical Regulations Conformity Certification, antenna power andantenna gain are measured separately the same as before. Especially, when antenna power isoperated more than 20mW/1mW as per mitigation in this revision, it is essential to measurecharacteristics of antenna gain.
[Adjustment of carrier sense level]
Because reception performance tends to be degraded when low gain antenna is used, thecarrier sense level shall be lowered according to the amount of the increase of antenna power inorder to ensure the carrier sense capability within communication area, as depicted in FigureS-4.

－3-12－

ARIB STD-T108

Figure S-4 Adjustment of carrier sense level

6.3 Updates from ARIB STD-T108 v1.1 to ARIB STD-T108 v1.2
This standard was revised to version 1.2 for the purpose of smooth operation of LPWA.
6.3.1 Channel extension of land mobile station (250 mW) passive sharing condition
In STD-T108 v1.1, a passive sharing condition (a condition to perform transmission of 4 s orless after 5 ms carrier sense and pause for 50 ms or more after 5 ms carrier sense) is performed
on a frequency channel with a center frequency of 920.6 MHz or more and 922.2 MHz or less inorder to implement uplink and downlink with the same channel, it was necessary to use afrequency channel with a center frequency of 920.6 MHz or more and 922.2 MHz or less.
However, since this frequency channel is a frequency channel mainly used by the passive tag
system, there is a possibility of interference.
To avoid that, the frequency channel that can use the passive sharing condition in the land
mobile station is extended to the same center frequency 920.6 MHz or more and 923.4 MHz orless as the ministerial ordinance.
However, for frequency channels with a center frequency of 922.4 MHz or more and 923.4
MHz or less, considering the influence on existing radio stations, the total transmission time perhour shall be 360 seconds or less. Also, it is desirable not to perform continuous transmission.
6.3.2 Conditions for frequency channel change
In order to improve the utilization efficiency of a system which operates while transiting a－3-13－

ARIB STD-T108
plurality of frequency channels, the provision of "pause of 10 times transmission time", which
was essential at the time of using a unit channel, is deleted
In addition, when moving over frequency channels, it is desirable to shift to a channel with afrequency as far as possible, in consideration of the influence on adjacent channels.

－3-14－

7 Channel plan for 920MHz-band radio equipment
Figure S-5 shows Channel allocation for 920MHz-band telemeter, telecontrol and data transmission radio equipment for convenience
radio stations and specified low power radio stations (Active system) and 920MHz-band RFID equipment for premises radio stations andspecified low power radio stations (Passive system).

T106

１W
Passive
１W・LBT Passive

930.0

927.8

928.0
928.15928.25928.35928.45928.55928.65928.75928.85928.95929.05929.15929.25929.35929.45929.55929.65
929.8

927.6

927.4

927.2

927.0

926.8

926.6

926.4

926.2

926.0

925.8

925.6

925.4

925.2

925.0

924.8

924.6

924.4

924.2

924.0

923.8

923.6

923.4

923.2

923.0

922.8

922.6

922.4

922.2

922.0

921.8

921.6

921.4

921.2

921.0

920.8

920.6

917.6

920.4

917.4

920.2

917.2

920.0

917.0

919.8

916.8

919.6

916.6

919.4

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
919.2

8

919.0

7

918.8

6

918.6

5

918.4

4

918.2

3

918.0

2

917.8

1

916.4

915.8

915.6

915.4

915.2

－3-15－

Center frequency

915.0

ch

916.2

250mW
Passive
250mW
Priority on active

916.0

T107

1mW

T108

20mW
Active20mW
Priory on passive
250mW
Active250mW
Priority on passive
C C C C C D D D D D D D D D D D D D D D D D D A A A A A A A A A B B B B B B
Passive tag system
Premises radio station（1W licensed station）

Premises radio station（1W registered station）

Specified low power
radio station （250ｍW）

Active system
Convenience radio
station （250ｍW）

Specified low power
radio station （20ｍW)

Specified low power
radio station （1ｍW）

Backscatter channels of
passive tag systems

Restrictions for A,B,C,D are specified in ARIB STD.

・〇(52ch－77ch）：1mW of transmission power is available before July 25th.
・◎（57ch-61ch）：20mW of transmission power is available before July 25th.
Other channels are not available before July 25th.

Channel plan for 920MHz-band radio equipment

ARIB STD-T108

・Freq. band A(24ch－32ch）：Priority channels for passive tag systems.
・Freq. band B（33ch-38ch）：Priority channels for active systems.
・Freq. band C（1ch-5ch）：Channels available for active tag systems for international logistics provided that backscatter channels of passive tag
systems (1ch-4ch) are securely protected.
・Freq. band D（6ch-23ch）：Channels for passive tag systems for secure protection of backscatter. (Active tag systems are not used in the time
being)

Figure S-5◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎○○○○○○○○○○○○○○○○

To: Secretariat of Standard Assembly Meeting of the Association of Radio Industries and Businesses
FAX: +81-3-3592-1103 E-mail:std@arib.or.jp
Nittochi Bldg. 11th Floor, 1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan

Communication Note of ARIB Standard-related Proposals, etc.
ARIB Standard
Name (No.)

920MHz-BAND TELEMETER, TELECONTROLAND DATA TRANSMISSION RADIO EQUIPMENT FOR
SPECIFIED LOW (ARIB STD-T108)
Sections to be completed by sender

Name:

Date

TEL:

FAX:

/

/

/

E-mail:Company name
Department name

Page / Section(Please describe your proposal or present your questions or comments in concrete terms.)

Sections to be completed by secretariat(Response)

Date of receipt
Ref. No.

//－Classification:
Remarks
Please send your ARIB Standard-related question in this format.
If you complete this form in English, please provide Japanese translation alongside the English.

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920MHz-BAND
TELEMETER, TELECONTROLAND DATA TRANSMISSION RADIO EQUIPMENT
ARIB STD-T108 Version 1.2

Version 1.0
Version 1.2

February 14th 2012
January 22th 2018

Published by
Association of Radio Industries and Businesses
11F, Nittochi Building,
1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, JapanTEL 03-5510-8590
FAX 03-3592-1103
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