1 
 Outline of Proposed Amendment to Ministerial Ordinance 
 
１ Item 
Partial amendment of Regulations for Radio Equipment etc. 
 
２ Amendment to Ministerial Ordinance 
    Regulations for Radio Equipment  
    Concerning Technical Regulations Conformity Certification of Specified Radio 
Equipment 
 
３ Reasons for amendment 
   The 920 MHz band Active Low Power Wireless systems are widely used for mobile 
identification, smart meters, sensor networks, etc. Recently, the Low Power Wide Area 
system (LPWA) which enables long-distance transmission with low power consumption 
is prevailing as sensor network, in addition to existing communication systems such as 
telemetry and telecommand. There is a growing demand for Active Low Power Wireless 
systems.  
While Japan requires that Active Low Power Wireless systems have a function of 
Carrier Sense (Listen-Before-Talk (LBT) system) to share frequencies among different 
wireless systems, other countries require that these systems have a function of 
Frequency Hopping (FH) system or Low Duty Cycle (LDC) system. This difference 
makes it necessary for Japan to adjust their functions of these systems imported by 
other countries. 
Considering this growing needs of new usage and international harmonization, Japan 
will amend the current technical regulations for 920MHz band Active Low Power 
Wireless systems.  
2 
 ４ Amendment Outline 
Item Technical requirements 
Name 920MHz band Active Low Power Wireless systems 
Frequency Allocation 920.5－923.5MHz 920.5－925.1MHz 
Occupied Bandwidth 200kHz 
Wireless channel mask The power emitted into the unit channel adjacent to the radio channel must 
be -15dBm or less. 
Antenna Power 20mW (13dBm) or less. However, if the transmitting antenna is contained in 
the housing of the radio equipment, it can't be opened easily and its 
equivalent isotropic radiation power is 16dBm (including the allowable 
deviation of the airborne power) or less, its transmitting power can be 
250mW or less. 
Allowable deviation of  
Antenna Power Max +20%，Min -80% 
Antenna Gain 3dBi or less. However, if equivalent isotropic radiation power is 16dBm 
(including the allowable deviation of the aerial power) or less, its antenna 
gain can be increased to compensate for the decrease of transmitting power. 
Allowable deviation of 
Frequency Within 20 × 10-6 or to be in the 
range of the designated frequency 
band including the occupied 
bandwidth. In the latter case, the 
center frequency of the unit channel 
is regarded as the assigned 
frequency, and the bandwidth of the 
unit channel is regarded to the 
width of the specified frequency 
band. Within 20 × 10-6 or to be in the range 
of the designated frequency band 
including the occupied bandwidth. In 
the latter case, the center frequency 
of the unit channel is regarded as the 
assigned frequency. 
Unwanted Emission 
Strength Appendix 1 
Secondary Radiated 
Emission Strength of 
receiving device Appendix 2  
3 
 Transmission spending 
Time Control The sum of the transmission time 
per hour of the transmission device 
must be 36 seconds or less. The sum of the transmission time per 
hour of the transmitter must be 720 
seconds or less.  
Crosstalk Prevention 
Function Automatically send or receive a code 
(identification code) to identify 
receiver/sender. 
Also it must have a LDC method 
function as follows: 
To stop the fire within 4 seconds of 
firing the radio wave, and not to 
transmit it after the 50-millisecond 
transmission pause time has 
elapsed. 
However, transmission can be 
performed without providing the 
transmission suspension time only 
when retransmission is performed 
within 4 seconds after the first radio 
wave is emitted (limited to 
retransmission that stops within 
the time). Automatically send or receive a code 
(identification code) to identify 
receiver/sender. Also it must have a 
FH method function as follows: 
To stop firing a specific frequency of 
radio waves within 400 milliseconds 
and, not to transmit radio waves of 
the same frequency until 4 seconds 
have elapsed. 
However, transmission can be 
performed without providing the 
transmission suspension time only 
when retransmission is performed 
within 400 milliseconds after the first 
radio wave is emitted (limited to 
retransmission that stops within the 
time). 
 
 Appendix 1（Unwanted Emission Strength） 
Frequency Limit value (Average) Reference Bandwidth 
 710MHz or less -36dBm 100kHz 
Over 710MHz - 900MHz or less -55dBm 1MHz 
Over 900MHz - 915MHz or less -55dBm 100kHz 
Over 915MHz - 930MHz or less -36dBm 100kHz 
Over 930MHz - 1GHz or less -55dBm 100kHz 
Over 1GHz - 1.215GHz or less -45dBm 1MHz 
Over 1.215GHz -30dBm 1MHz 
  
4 
 Appendix 2（Secondary Radiated Emission Strength of receiving device） 
Frequency Limit value (Average) Reference Bandwidth 
 710MHz or less -54dBm 100kHz 
Over 710MHz - 900MHz or less -55dBm 1MHz 
Over 900MHz - 915MHz or less -55dBm 100kHz 
Over 915MHz - 930MHz or less -54dBm 100kHz 
Over 930MHz - 1GHz or less -55dBm 100kHz 
Over 1GHz -47dBm 1MHz 
 
５ Proposed date of entry into force 
May, 2020