RSS-102.SAR.MEAS — Measurement Procedure for Assessing Specific Absorption Rate (SAR) Compliance in Accordance with RSS-102

Issue 1
December 15, 2023

Gazette notice SMSE-015-23

Amendment (May 2024)

Bullet a. of Annex G.3.6 was edited to read: Single point SAR measurements need be performed only for changes in requested power, as described in sections G.3.7 to G.3.9 below.

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Preface

Radio Standards Specification RSS-102.SAR.MEAS, Measurement Procedure for Assessing Specific Absorption Rate (SAR) Compliance in Accordance with RSS-102, issue 1, replaces the following documents:

  1. Supplementary Procedure SPR-001, SAR Testing Requirements With Regard to Bystanders for Laptop Type Computers with Antennas Built-In On Display Screen (Laptop Mode/Tablet Mode), dated January 1, 2011
  2. SPR-004, Time-Averaged Specific Absorption Rate (TAS) Assessment Procedures for Wireless Devices Operating in the 4 MHz to 6 GHz Frequency Band, issue 1, dated June 18, 2021
  3. SPR-APD, Supplementary Procedure for Assessing Specific Absorption Rate (SAR) and Absorbed Power Density (APD) Compliance of Portable Devices in the 6 GHz Band (5925-7125 MHz), issue 1, dated June 2, 2022

This document is associated with the modernization of RSS-102, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands). SAR-related procedures are consolidated into this document to simplify the identification of procedures related to SAR testing.

The main changes are listed below:

  1. new requirements to assess compliance of hand SAR during voice calls
  2. revised maximum separation distance for SAR
  3. clarified accepted test procedure for foldable devices
  4. integration of the contents of SPR-001, the SAR-related provisions of SPR-002, SPR-004, SPR-APD, and various SAR-related notices
  5. various editorial changes

Inquiries may be submitted by one of the following methods:

  1. Online using the General Inquiry form (in the form, select the Directorate of Regulatory Standards radio button and specify “RSS-102” in the General Inquiry field)
  2. By mail to the following address:

    Innovation, Science and Economic Development Canada
    Engineering, Planning and Standards Branch
    Attention: Regulatory Standards Directorate
    235 Queen St
    Ottawa ON K1A 0H5
    Canada
  3. By email to consultationradiostandards-consultationnormesradio@ised-isde.gc.ca

Comments and suggestions for improving this standard may be submitted online using the Standard Change Request form, or by mail or email to the above addresses.

All Innovation, Science and Economic Development Canada publications related to spectrum management and telecommunications are available on the Spectrum management and telecommunications website.

Issued under the authority of

the Minister of Innovation, Science and Industry

____________________________________

Martin Proulx

Director General

Engineering, Planning and Standards Branch

1. Scope

This Radio Standards Specification (RSS) sets out the specific absorption rate (SAR) compliance requirements for all equipment operating in the 100 kHz to 6 GHz frequency band. Note that some provisions are included for the application of SAR measurements to evaluate compliance to absorbed power density (APD) limits of portable devices operating in the 6 GHz band (5925-7125 MHz).

1.1 Purpose and application

This standard shall be used with other applicable RSSs. This document outlines the measurement-based assessments of devices subject to SAR compliance limits. This document is intended to replace the SAR provisions contained in:

  • RSS-102, issue 5, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands)
  • Supplementary Procedure SPR-001, issue 1, SAR Testing Requirements With Regard to Bystanders for Laptop Type Computers With Antennas Built-In on Display Screen (Laptop Mode/Tablet Mode)
  • SPR-002, issue 2, Supplementary Procedure for Assessing Compliance of Equipment Operating from 3 kHz to 10 MHz with RSS-102
  • SPR-004, issue 1, Time-Averaged Specific Absorption Rate (TAS) Assessment Procedures for Wireless Devices Operating in the 4 MHz to 6 GHz Frequency Band
  • SPR-APD, issue 1, Supplementary Procedure for Assessing Specific Absorption Rate (SAR) and Absorbed Power Density (APD) Compliance of Portable Devices in the 6 GHz Band (5925-7125 MHz)

1.2 Transition period

This document will be in force as of the date of its publication on Innovation, Science and Economic Development Canada’s (ISED) website. However, a transition period of 12 months from the publication date will be provided, within which compliance with the SAR provisions in the documents listed in section 1.1, above, and RSS-102.SAR.MEAS, issue 1, will be accepted. After this period, only applications for the certification of equipment under the provisions of RSS-102.SAR.MEAS, issue 1, will be accepted. Furthermore, after this transition period, equipment that is manufactured, imported, distributed, leased, offered for sale, or sold in Canada shall comply with RSS-102.SAR.MEAS, issue 1.

A copy of RSS-102, issue 5, SPR-001, issue 1, SPR-002, issue 2, SPR-004, issue 1, or SPR-APD, issue 1, is available upon request by emailing consultationradiostandards-consultationnormesradio@ised-isde.gc.ca.

2. Normative references

The documents that are listed on the Radio Frequency (RF) Exposure Normative References and Acceptable Knowledge Database web page shall be consulted as applicable and available, in conjunction with this RSS.

ISED may consider assessment methods not covered by RSS-102.SAR.MEAS or the referenced publications. Consult ISED’s Certification and Engineering Bureau website to determine the acceptability of any alternative measurement methods, or send an inquiry by emailing certificationbureau-bureauhomologation@ised-isde.gc.ca with detailed information on the alternative assessment method(s).

3. Definitions, abbreviations/acronyms and quantities

This section provides definitions and abbreviations/acronyms for terms used in this document, as well as the symbols/units used for quantities.

3.1 Definitions

In addition to the terms defined in RSS-102, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands), the following terms and definitions apply to this standard.

Absorbed power density (APD) evaluation: The method used to evaluate APD levels from a device by physical measurement. An APD evaluation is required for devices operating at a frequency greater than 6 GHz and if the separation distance between the user or bystanders and the device is less than or equal to 20 cm.

Averaging region: The averaging volume used for averaging the SAR or the surface area on the evaluation surface used for averaging the APD. For SAR assessments at frequencies less than or equal to 6 GHz band, 1 g or 10 g tissue volume is used for head/neck/trunk and limbs respectively. For APD assessments at frequencies above the 6 GHz band, the averaging area is defined as a 4 cm2 square. This is equivalent to 8 g tissue volume.

Body-supported device: A device whose intended use includes transmitting with any portion of the device being held directly against a user’s body (e.g. a laptop computer).

Body-worn (or body-mounted) device: A wireless transceiver that is designed to be worn or carried on the body of a person. This includes wireless communication devices that are attached to or integrated in clothing or accessories such as lanyards, clothing-integrated devices, or belts.

Conducted power: The power delivered by the RF transmitter within the device to a matched load, e.g. 50 Ω.

Laptop mode: The operating configuration where the display is open perpendicular to and facing towards the keyboard.

Limb-worn device: A device containing one or more wireless transmitters or transceivers that is designed or intended for use on or to be operated only by the limbs. It includes being strapped to the arm or leg of the user while transmitting.

Peak spatial-average power density: The global maximum value of all spatial-average power density values defined on the evaluation surface.

Radio frequency (RF) exposure limit: The limit pertaining to an electric field, a magnetic field or a power density that applies to the RF exposure evaluation.

Reference period: The time period (of 360 seconds) used for averaging temporally non-uniform RF field exposures. Exposures lasting less than the reference period may exceed the RF exposure limits, provided that the averaged exposure over the reference period does not exceed the RF exposure limits.

Single point specific absorption rate: The measured specific absorption rate (SAR) value at a single or local point. Single point SAR is not averaged within a local region based on a mass of tissue (1 g or 10 g).

Spatial peak power density: The global maximum value of the power density values defined on the evaluation surface.

Note: Unlike the peak spatial-average power density, this value is not averaged.

Tablet mode: For a convertible tablet computer, the operating configuration where the display is folded over onto the keyboard section and facing outwards. The display orientation may be switched between portrait or landscape configurations for both slate and convertible tablets, allowing one or more of the tablet edges to become closest to the user during normal use.

3.2 Abbreviations/acronyms

This document uses the following abbreviations and acronyms:

APD
absorbed power density
CDF
cumulative density function
dB
decibel
dBm
dB relative to 1 milliwatt
EUT
equipment under test
ER
exposure ratio
FCC
Federal Communications Commission
FDD
frequency-division duplexing
FFT
Fast Fourier Transform
Hz
Hertz
IEC
International Electrotechnical Commission
IEEE
Institute of Electrical and Electronics Engineers
ISED
Innovation, Science and Economic Development Canada
KDB
knowledge database
NS
nerve stimulation
PD
power density
pPD
spatial peak power density
psPD
peak spatial-average power density
psSAR
peak spatial-averaged specific absorption rate
PTT
push-to-talk
QAM
quadrature amplitude modulation
QPSK
quadrature phase shift keying
REL
Radio Equipment List
RF
radio frequency
RLAN
radio local area network
RMS
root mean square
SAM
specific anthropomorphic mannequin
SAR
specific absorption rate
SI
International System of Units
TAS
time-averaged specific absorption rate
TDD
time-division duplexing
TDMA
time-division multiple access
TER
total exposure ratio
WLAN
wireless local area network
WPT
wireless power transfer
WWAN
wireless wide area network
UMPC
ultra-mobile personal computer

3.3 Quantities

Table 1 lists the quantities used throughout this document along with their internationally accepted SI units (where applicable).

Table 1: Quantities
Quantity Symbol Unit
Magnetic flux density B tesla (T)
Base unit of length m metre (m)
Electric field strength E volts per metre (V/m)
Exposure ratio ER unitless
Frequency f hertz (Hz)
Mass g gram (g)
Magnetic field strength H amperes per metre (A/m)
Current I ampere (A)
Total exposure ratio TER unitless
Power W watt (W)
Specific absorption rate SAR watts per kilogram (W/kg)
Voltage V volt (V)
Wavelength λ metre (m)

Note that common SI prefixes are permitted to be employed with the quantities outlined in table 1 where appropriate.

4. General requirements

This section outlines the general requirements for compliance assessment of equipment under test (EUT) operating from 100 kHz to 6 GHz.

4.1 Exposure limits, use cases and exposure conditions

Radiocommunication apparatus shall comply with the limits outlined in Health Canada’s Safety Code 6, which are adopted in RSS-102. As set forth in RSS-102, SAR compliance of portable devices shall be assessed against the basic restriction limits.

Use-cases and operating configurations shall be identified and described in the RF exposure technical brief. It shall be clear how the user and/or bystander foreseeably interacts with the EUT. Key RF exposure conditions shall be identified using this information. The objective of the exposure assessment is to demonstrate compliance with the applicable limits for each exposure condition.

Although international standards such as IEC/IEEE 62209-1528, Measurement procedure for the assessment of specific absorption rate of human exposure to radio frequency fields from hand-held and body-worn wireless communication devices - Human models, instrumentation and procedures (Frequency range of 4 MHz to 10 GHz), define procedures to evaluate SAR up to 10 GHz, as per Health Canada’s Safety Code 6, SAR assessment shall only be performed up to 6 GHz to assess RF exposure compliance. Above 6 GHz, power density is the appropriate metric to assess RF exposure compliance.

4.2 Separation distance

The separation distance is the minimum distance between the EUT and the nearest surface of the exposure region of a user and/or bystander, i.e. the region over which RF exposure is to be evaluated. It is based on both the key RF exposure conditions identified in section 4.1 and the nature of the exposure limit under consideration. The limits to prevent thermal effects are based on average exposure over any 6 minute period. Consequently, the nerve stimulation- (NS) and SAR-based separation distances may be different.

Each separation distance applied during the assessment(s) shall be clearly identified in the RF exposure technical brief for each exposure type.

5. Measurement-based assessments

This section and the referenced normative annexes set out the requirements applicable to radio transmitters subject to this standard.

5.1 SAR evaluation methods, SAR test reductions and fast SAR

The following sections outline the SAR evaluation methods, SAR test reductions and the applicability of fast SAR.

5.1.1 SAR evaluation methods

SAR evaluations in the range of 100 kHz to 4 MHz shall be completed in accordance with section 5.7, below.

SAR evaluations in the range of 4 MHz to 6 GHz shall be made in accordance with the latest version of IEC/IEEE 62209-1528 with the deviations outlined below.

SAR evaluations shall also be compliant with the following deviations:

  • Clause 7.6 of IEC/IEEE 62209-1528 is not applicable for device certification. Instead the provisions of annex G of this RSS shall be followed.
  • The SAR assessment procedures for Long-Term Evolution (LTE) devices provided in Federal Communications Commission (FCC) knowledge database (KDB) 941225 D05 take precedence over clause 7.9.3.6 of IEC/IEEE 62209-1528.

ISED accepts the fast SAR testing procedures set forth in clause 7.9.2 of IEC/IEEE 62209-1528.

The procedures of IEC 62209-3, Measurement procedure for the assessment of specific absorption rate of human exposure to radio frequency fields from hand-held and body-mounted wireless communication devices - Part 3: Vector measurement-based systems (Frequency range of 600 MHz to 6 GHz), are not accepted for device certification.

However, consistent with IEC/IEEE 62209-1528, Class 2 fast SAR systems compliant with IEC 62209-3 are permitted to be used to identify the worst case SAR test configurations (relative SAR measurements) that shall subsequently be measured with full SAR testing to assess compliance (absolute SAR measurements) against the RSS-102 requirements.

5.1.2 SAR test reductions

ISED’s SAR test reductions provisions are outlined in the following sections.

5.1.2.1 General requirements

ISED accepts test reductions provided that the method is either:

  • defined in the RSS-102 family of standards
  • allowed in a normative section of IEC/IEEE 62209-1528
  • from a United States FCC KDB procedure referenced in this standard
5.1.2.2 SAR data re-use on depopulated variants from a reference model

SAR data re-use or test reduction for depopulated variant model(s) based on SAR test data from a reference model may be permitted.

An inquiry shall be submitted to obtain pre-approval from ISED prior to submitting depopulated variant model(s) for certification. Such a request shall be sent to ISED’s Certification and Engineering Bureau at the following email address: certificationbureau-bureauhomologation@ised-isde.gc.ca.

The following requirements are considered in the assessment of SAR data re-use requests on depopulated variants from a reference model:

  1. The reference model should be certified in Canada (even if it is not intended for sale).
  2. In all situations, the applicant shall fully test the reference model to ascertain compliance with all applicable requirements set forth in applicable Radio Standards Specifications.
  3. Compliance data shall not be re-used for the certification of a variant model if the test report submitted to demonstrate the compliance of the reference model is more than 1 year old and/or if more stringent requirements (e.g. change in limit, change in measurement procedure) have come into force after the certification of the reference model.
  4. The reference model’s certification number shall be clearly identified in the variant model’s RF exposure technical brief.
    If the certification number of the reference model is not available, another unique identification number (e.g. model number) is permitted provided this identification number is publicly available and can be easily used to identify the reference model.
  5. The acceptance of data re-use will be dependent on spot checks being performed for conducted power and SAR.
  6. Simultaneous transmission shall be considered when demonstrating overall compliance.
  7. For standalone transmission, the following conditions shall be met:
    1. The conducted power of the variant model(s) shall be within the manufacturer’s tune-up tolerance. If tune-up tolerance(s) are exceeded, ISED shall be consulted.
    2. If the worst-case reported SAR value in the reference model’s original RF exposure technical brief is less than or equal to 75% of the applicable SAR limits (1.2 W/kg for head/body configuration, or 3 W/kg for limb configuration), spot checks must be performed on each depopulated variant for:
      1. The worst-case of each configuration identified by the reference model. Spot checks shall be performed separately for the worst-case head, body and limb SAR whenever applicable. For example, if both head SAR and body SAR are listed in the Radio Equipment List (REL), at least two spot check measurements are to be done, one for head and one for body.
      2. Where the worst-case SAR value for the spot check is above 30% of the associated worst-case SAR in the reference model’s SAR report, additional testing shall be performed (following the guidance provided in 7.c.i., below).
    3. If the worst-case reported SAR value in the original RF exposure technical brief of the reference model is above 75% of applicable SAR limits, spot checks must be performed on:
      1. The worst-case test configurations identified for the reference model for each antenna, each frequency band, and each technology.
      2. If any of the worst-case SAR values for the spot checks are above 30% of the SAR values in the original SAR report for the reference model, full testing is required.
  8. Where depopulated variant models share identical hardware but have different firmware than the reference model:
    1. All data and reports being used for certification of the depopulated variant model must be in accordance with RSS-102 and procedures accepted by reference.
    2. Spot checks on the variant model must be carried out if the reference model has any SAR values >75% of applicable SAR limits. The spot checks would consist of the worst-case of each configuration on the variant model.
    3. If the variant model has any unique RF power settings or features that provide enhanced/augmented capabilities that may alter RF characteristics (for any band or technology) compared to the reference model, then the variant model shall be tested in full for that band.
  9. All reports need to:
    1. Identify the models tested.
    2. Identify the differences in the models (making it clear if it is hardware only, software only or both hardware and software).
    3. Include only data for the bands/modes/features supported by the variant model(s) in order to clearly identify the highest RF exposure values for Canada; or identify the data for the bands/modes/features that are not supported by the variant model if included in the RF exposure technical briefs.
  10. With regards to controlled-use devices, the SAR limits for controlled environment shall apply.
  11. The reference model SAR report shall be included in the certification application.

Notwithstanding the above conditions, ISED may request full testing of variant models if deemed necessary.

For reporting purposes, the final reported SAR value(s) of a variant model shall be the worst-case value(s) from either the reference model or from the spot check testing.

For all other test reduction scenarios not covered in section 5.1.2, the applicant shall consult with ISED prior to initiating the certification process. Such a request shall be sent to ISED’s Certification and Engineering Bureau at the following email address: certificationbureau-bureauhomologation@ised-isde.gc.ca.

5.2 Calibration and system verification

Calibration and system verification shall be completed in accordance with IEC/IEEE 62209-1528.

Additionally, for dipoles, longer calibration intervals of up to three years may be considered when it is demonstrated that the SAR target, impedance and return loss of a dipole have remained stable according to the following requirements:

  1. The test laboratory must ensure that the required supporting information and documentation are included in the SAR report to qualify for the three-year extended calibration interval; otherwise, the dipole manufacturer’s recommended calibration applies.
  2. Immediate recalibration is required for the following conditions:
    1. After a dipole is damaged and properly repaired to meet required specifications.
    2. When the measured SAR deviates from the calibrated SAR value by more than 10% due to changes in physical, mechanical, electrical or other relevant dipole conditions (i.e. the error is not introduced by incorrect measurement procedures or other issues relating to the SAR measurement system).
    3. When the most recent return loss result, measured at least annually, deviates by more than 20% from the previous measurement or not meeting the required 20 dB minimum return loss requirement.
    4. When the most recent measurement of the real or imaginary parts of the impedance, measured at least annually, deviates by more than 5 Ω from the previous measurement.

5.3 Measurement provisions

In addition to the SAR standards mentioned in section 5.1, the following provisions shall apply when performing a SAR evaluation:

  1. All SAR measured quantities shall be scaled to the maximum tune-up tolerance of the device.
  2. If a device has push-to-talk (PTT) capability, a minimum duty cycle of 50% (on-time) shall be used in the evaluation. A duty cycle lower than 50% is permitted only if the transmission duty cycle is an inherent property of the technology or of the design of the equipment and is not under user control. Proof of the various on-off durations and a detailed method of calculation of the average power shall be included in the RF exposure technical brief. Maximum average power levels shall be used to determine compliance.
  3. For devices without push-to-talk capability, the duty cycle used in the evaluation shall be based on the inherent property of the transmission technology or of the design of the equipment.
  4. If the device is designed to operate in front of the mouth, such as PTT radio, it shall be evaluated with the front of the device positioned at 2.5 cm from a flat phantom. For wristwatch and wrist-worn transmitters in speaker mode for voice communication, evaluations shall be conducted with the front of the devices positioned 1.0 cm from the flat phantom. If the device is also designed to operate when placed next to the cheek and ear, it shall also be tested against the SAM phantom.
  5. Low transmission duty factor devices (e.g. point-of-sale devices, black and white e-readers, and location trackers) that only transmit intermittently in data mode and without voice capability may be exempt from routine SAR evaluation if the exemption limits from routine evaluation outlined in RSS-102 are met by applying the worst-case or most conservative transmission duty factor. The supporting details for determining the duty factor with respect to the design, implementation, operating configurations and exposure conditions of the devices must be fully documented in the RF exposure technical brief.
  6. SAR evaluation of medical implants (e.g. Medical Implant Communication System and Medical Implant Telemetry System) devices shall be performed by physical measurement or computational modelling.
  7. The mid-channel of a transmission band shall first be tested in the SAR evaluation. However, if the variation of the maximum output power across the required test channels is more than 0.5 dB above the output power of the mid-channel, the channel with the highest output power shall first be tested (if different from the mid-channel). The method for determining the maximum output power, as well as the value of each channel, shall be documented in the RF exposure technical brief.

5.4 Body-worn devices

In addition to the SAR standards mentioned in section 5.1, above, the following provisions shall apply when performing SAR measurements for body-worn devices:

  1. Body-worn accessories (e.g. belt clips and holsters) shall be attached to the device and positioned against the flat phantom in normal use configurations.
  2. When multiple accessories supplied with the device or made available by the manufacturer for the device contain no metallic components, the device shall be tested with the accessory that provides the shortest separation distance between the device and the body.
  3. When multiple accessories supplied with the device or made available by the manufacturer for the device contain metallic components, the device shall be tested with each accessory containing a unique metallic component. If multiple accessories share the same metallic component, only the accessory providing the shortest separation distance between the device and the body shall be tested.
  4. If accessories are neither supplied nor made available by the manufacturer, a conservative minimum separation distance based on off-the-shelf body-worn accessories should be used to test body-worn devices. A separation distance of 10 mm or less between the device and the phantom is required. The device shall be positioned with either its back surface or front surface toward the phantom, whichever will result in the higher SAR value. If this cannot be determined, both positions shall be tested and the higher of the two SAR values shall be included in the RF exposure technical brief cover sheet. The selected separation distance shall be clearly explained in the RF exposure technical brief to support the body-worn accessory test configurations.
  5. Body-worn devices that are designed to operate on the body using lanyards or straps shall be tested using a test separation distance of 5 mm or less.
  6. The head equivalent liquid for SAR measurement of body-worn devices shall be used. Information related to the tissue equivalent liquid shall be included in the RF exposure technical brief.

5.5 Devices containing multiple transmitters

Compliance of devices with multiple transmitters capable of simultaneous transmission shall be assessed in accordance with the latest version of IEC/IEEE 62209-1528 and section 8 of RSS-102.

Alternatively, any procedures published by the FCC that have been accepted by ISED may also be used. Applicants shall include all information relevant to the exact test methodology used in the RF exposure technical brief.

5.6 Procedures related to specific technologies and types of devices

SAR measurement procedures for transmitters associated with the technologies listed below may not be available in the current international standards:

  • wireless wide area networks (WWANs) employing 5G and beyond
  • wireless local area networks (WLANs) such as recent variants of IEEE 802.11-based networks
  • devices with novel form factors and exposure conditions

The recognized procedures, such as FCC RF exposure KDB procedures, referenced on ISED’s Acceptable knowledge database, other supplementary procedures and notices web page can be used as an interim measure until these standards contain the measurement procedures for these specific technologies and types of devices. Applicants shall include all information relevant to the exact method used in the RF exposure technical brief.

5.6.1 Foldable phones

Foldable phones that support tablet or ultra-mobile personal computer (UMPC) mini-tablet operating characteristics shall continue to be assessed as per the provisions of FCC KDB 941225 and FCC KDB 616217:

  • foldable phones with a display or an overall diagonal dimension ≤ 20 cm shall continue to be assessed less than or equal to 5 mm separation distance from the flat phantom
  • foldable phones with a display or an overall diagonal dimension > 20 cm shall continue to be assessed at 0 mm separation distance from the flat phantom

However, for compliance with ISED requirements, the provisions for separation distance up to 10 mm for certain dual display devices mentioned in KDB 941225 do not apply. Inquiries to increase the separation distance to 10 mm for foldable phones will not be accepted by ISED.

5.6.2 Application-specific phantoms

The provisions of IEC/IEEE 62209-1528, including the normative annex K (where the application-specific phantoms are described), were adopted by reference and came into force.

Figure 1: Face-down SAM phantom

Description of figure 1

This figure shows a SAM head phantom that is facing down. The top of the phantom is open.

The face-down SAM phantom is intended for devices where the exposure is at the front side of the head or devices where transmitters are mounted on eyeglasses or eyewear.

 

Figure 2: Head-stand SAM phantom

Description of figure 2

This figure shows a SAM head phantom that is standing upside down. The top of the phantom is open.

The head-stand SAM phantom is intended for devices where the exposure is at the top side of the head (e.g. head-mounted devices)

 

Figure 3: Wrist phantom

Description of figure 3

This figure shows a wrist phantom. It is cylindrical with the top being larger than the bottom. The top of the phantom is open.

The wrist phantom is intended for wrist-worn wearable devices such as watches, bracelets, etc.

 

ISED notes that testing without application-specific phantoms can lead to the following problems due to the non-standardized positioning:

  • unrepeatable/unreproducible measurements
  • larger measurement uncertainty contributions, due to non-standardized areas of the SAM phantom being used

In the event a testing laboratory is unable to perform the RF exposure assessment with an application-specific phantom, the testing laboratory shall request permission to use a different phantom by providing ISED with a detailed rationale as to why the application-specific phantom cannot or should not be used. Such a request shall be sent to ISED’s Certification and Engineering Bureau at the following email address: certificationbureau-bureauhomologation@ised-isde.gc.ca. ISED will review these requests on a case-by-case basis.

Note: Watches with a flat back surface can continue to be tested with a flat phantom without requesting permission.

In all cases, ISED notes that when performing market surveillance on devices subject to application-specific phantom evaluations, the relevant phantom will be used to assess compliance with its requirements.

5.7 Devices with transmitters operating between 100 kHz and 4 MHz

Refer to annex B for SAR measurements of devices with transmitters operating between 100 kHz and 4 MHz.

Refer to annexes C and D of RSS-102.NS.MEAS, Measurement Procedure for Assessing Nerve Stimulation (NS) Compliance in Accordance with RSS-102, for SAR measurements for wireless power transfer (WPT) applications and various device types operating between 100 kHz and 10 MHz, respectively.

5.8 Bystander exposure from laptop computers

Refer to annex C for SAR measurements for bystander exposure from laptop computers.

5.9 Laptop computers with an antenna integrated in the keyboard section

Refer to annex D for SAR measurements of laptop computers with an antenna integrated in the keyboard section.

5.10 Hand exposure during next-to-head voice calls

In addition to the SAR standards mentioned in section 5.1, above, the procedure in annex E shall be performed to demonstrate compliance of devices that:

  • are capable of next-to-head voice calls where the audio is routed to the earpiece
  • have transmitting antennas on the bottom half of the device
  • employ higher power levels in voice call than in interactive hand use exposure cases

The provisions in annex E are optional for devices that do not meet one or more of the requirements above.

5.11 Portable devices operating in the 6 GHz band (5925-7125 MHz)

Refer to annex F for SAR and SAR-based APD measurements of devices operating in the 5925-7125 MHz band.

In addition, should the EUT support next-to-head voice calls, the procedure in section E.2 of annex E shall be performed to demonstrate compliance.

Note that the test reduction methods in section E.1 of annex E would not apply.

5.12 Time-averaged SAR

Refer to annex G for the general test methods to use in assessing the compliance of final products implementing time-averaged specific absorption rate (TAS) algorithms approved by ISED.

6. Radio frequency exposure technical brief

The applicant shall prepare an RF exposure technical brief that contains the general information listed in section 4.2 of RSS-102, the technical details described in annex A of this document and all of the relevant information to document APD assessments and TAS validation, as applicable.

RF exposure technical briefs are required to include the exact test configuration(s), equipment calibrations, equipment and measurement/computational uncertainty budgets, system validation/system checks, tissue dielectric parameters, as well as all other relevant technical information. Device test positions shall be documented, including graphical representations showing separation distances and tilt angles used during the evaluation. The rationale for the selection of the separation distance(s) between the device and the phantom shall be included. Close-up photos of the actual device in the various test positions shall also be included.

Refer to annex A of this document and annex A of RSS-102 for additional information.

Annex A: Information required in the radio frequency exposure technical brief to document specific absorption rate (normative)

This annex provides a comprehensive summary of the information that must be included in the radio frequency (RF) exposure technical brief to demonstrate compliance with RSS-102.SAR.MEAS.

Section A.1 lists information on the test device and exposure category. Section A.2 lists specific information for specific absorption rate (SAR) measurements.

A.1 Information on the test device and exposure category

(1) General information

  • ISED certification ID
  • Model number
  • RF exposure environment (general public/controlled use)

(2) Device operating configurations and test conditions

  • Test device is a production unit or an identical prototype
  • Brief description of the test device operating configurations, including:
    • illustration(s) of the antenna position(s) relative to the equipment under test, including dimensions and separation distances (for multiple transmitters/antennas), as applicable
    • operating mode(s) and operating frequency range(s)
    • maximum output power of the device for each operating mode and frequency range
    • maximum tune-up tolerances (i.e. variation in output power of the applicable test channels)
    • antenna type with gain and operating positions
    • applicable head, body-worn, body-supported and/or limb-worn configurations
    • battery options that could affect the SAR results
    • description of the test mode software including the version number and what the software was used to control or configure as applicable (including but not limited to antenna selection, signaling, power tables, WIFI/Bluetooth, dynamic antenna tuning, control time-averaged SAR algorithm parameters, etc.)
  • Procedures used to establish the test signals
  • Detailed description of the communication protocols used during the evaluation
  • Applicable source-based time-averaging duty factor and the duty factor used in the tests
  • Maximum output power or local SAR measured before and after each SAR test

A.2 Specific information for SAR measurements

(1) Measurement system and site description

  • Brief description of the SAR measurement system
  • Brief description of the test set-up

(2) Electric field probe calibration

  • Description of the probe, its dimensions and sensor offset, etc.
  • Description of the probe measurement errors
  • Most recent calibration date and associated calibration certificate

(3) SAR measurement system check

  • Description of system check procedure, including any non-standardized methods/calculations used to determine the system check target value(s)
  • Brief description of the RF radiating source used to verify the SAR system performance within the operating frequency range of the test device
  • List of the tissue dielectric parameters, ambient and tissue temperatures and output power
    • the peak and 1 g or 10 g averaged SAR for the measured and expected target test configurations shall be provided in a tabulated format
    • all parameters provided in the table shall match the values in the system check plots
  • List of the error components contributing to the total measurement uncertainty
  • SAR plots of all system check measurements to demonstrate system functionality/compliance
  • Most recent calibration dates for dipoles and the associated calibration certificates
  • Measurement data to support the extension of the dipole calibration interval to three years, if applicable

(4) Phantom description

  • Description of the head and/or body phantoms used in the tests, including shell thickness and other tolerances

(5) Tissue dielectric property

  • Composition of ingredients for the tissue material used in the SAR tests
  • Tissue dielectric parameters measured at the low, middle and high frequency of each operating frequency range of the test device in tabulated format
  • Temperature range and operating conditions of the tissue material during each SAR measurement

(6) Device positioning

  • Description of the dielectric holder or similar mechanisms used to position the test device in the specific test configurations
  • Description of the positioning procedures used to evaluate the highest exposure expected under normal operating configurations
  • Sketches and illustrations showing the device positions with respect to the phantom, including separation distances and angles, as appropriate
  • Description of the antenna operating positions (extended, retracted or stowed, etc.) and the configurations tested in the SAR evaluation

(7) Peak SAR locations

  • Description of the coarse resolution, surface or area scan procedures used to search for all possible peak SAR locations within the phantom
  • Description of the interpolation procedures applied to the measured points to identify the peak SAR locations at a finer spatial resolution
  • Description, illustration and SAR distribution plots showing the peak SAR locations with respect to the phantom and the test device
  • Identifying the peak SAR locations used to evaluate the highest 1 g averaged SAR

(8) 1 g / 10 g averaged SAR

  • Description of the fine resolution, volume or zoom scan procedures used to determine the highest 1 g averaged SAR in the shape of a cube
  • Description of the extrapolation procedures used to estimate the SAR value of points close to the phantom surface that are not measurable
  • Description of the interpolation procedures applied to the measured and extrapolated points to obtain SAR values at a finer spatial resolution within the zoom scan volume
  • Description of the integration procedures applied to the interpolated SAR values within the zoom scan volume to determine the highest 1 g SAR in the shape of a cube

(9) Total measurement uncertainty

  • Tabulated list of the error components and uncertainty values contributing to the total measurement uncertainty
  • Combined standard uncertainty and expanded uncertainty (for k≥2) of each measurement
  • If the expanded measurement uncertainty is greater than the target value per the referenced standard (e.g. IEC/IEEE 62209-1528), an explanation of the procedures that have been used to reduce the measurement uncertainty shall be provided

(10) Test reduction

  • All information, including description (with drawings and photograph, if required) and rationale, related to specific test reduction procedures

(11) Fast SAR techniques

  • Description of measurement system main components and software; equipment list of the test equipment and accessories used to perform fast SAR measurements and used to verify the fast SAR system, as well as to characterize the tissue dielectric parameters
  • Detailed calibration data relevant to critical fast SAR measurement system components
  • Description of the interpolations and extrapolations algorithms used in the area scans and zoom scans
  • Description of the fast SAR method validation, including results of the computations and measurements to validate the fast SAR method
    • Radiating source description and SAR distribution for each frequency band, SAR tolerance and details of any modifications to post-processing algorithms
  • Results of the system check for each frequency band, deviation from target value and radiating source description
  • Measurement uncertainty budget for each frequency band, system validation uncertainty evaluation, and system check uncertainty evaluation, including any other relevant information pertaining to measurement uncertainty
  • Tabulated list of all frequency bands, modulation, test configurations testing using a fast SAR method with SAR results
  • Tabulated and graphical results for the highest fast SAR measurement for each frequency band and modulation
  • Results of all full SAR tests performed, which include the peak spatial-average SAR value for each required test and graphical representation of the scans with respect to the device

(12) Test results for determining SAR compliance

  • If the channels tested for each configuration (left, right, cheek, tilt/ear, extended, retracted, etc.) have similar SAR distributions, a plot of the highest SAR for each test configuration should be sufficient; otherwise, additional plots should be included to document the differences
  • All of the measured SAR values should be documented in a tabulated format with respect to the test configurations
    • the reported SAR shall be scaled to the maximum tune-up tolerance of the device
  • SAR plots shall also contain information regarding compliance to sections 7.4.2 4) i) and 7.4.2 4) ii) of IEC/IEEE 62209-1528
  • SAR plots shall match all supporting information within the RF exposure technical brief (tissue dielectric parameters, SAR values, drift, calibration dates, probe conversion factors, etc.)
  • SAR plots shall not be edited from what is reported by the system

Annex B: Assessments of equipment under test operating from 100 kHz to 4 MHz

This annex provides the requirements related to measurement-based specific absorption rate (SAR) assessments against the reference levels in the frequency range of 100 kHz to 4 MHz. The test set-up employed for SAR measurements in this band is similar to that employed for nerve stimulation (NS) measurements as outlined in RSS-102.NS.MEAS, Measurement Procedure for Assessing Nerve Stimulation (NS) Compliance in Accordance with RSS-102, due to the overlap in the applicable frequency range.

B.1 Operational description of the equipment under test

An operational description of the equipment under test (EUT) in accordance with section 4.3 of RSS-102.NS.MEAS shall be provided.

B.2 Assessment methods

The available assessment methods for assessing radio frequency (RF) exposure from emissions produced by the EUT in the range of 100 kHz to 4 MHz are outlined in the following sections.

B.2.1 Basic restrictions

For a given EUT, RF exposure condition, and corresponding separation distance, the SAR within the body shall not exceed the applicable basic restrictions.

Measurement of the induced SAR within a representative tissue-equivalent phantom at the corresponding separation distance is the preferred assessment method. However, this may not always be feasible due to physical constraints, or the availability of suitable test equipment, tissue-equivalent phantom definitions and/or conservative assessment procedures. Consequently, simulation-based assessments in accordance with RSS-102.SAR.SIM, Simulation Procedure for Assessing Specific Absorption Rate (SAR) Compliance in Accordance with RSS-102 (currently in development) or measurements as outlined in section B.2.2, below, shall be completed.

B.2.2 Reference levels

This section specifies requirements related to assessments based on reference levels. Reference levels provide a means of assessing exposure based on incident field strengths instead of induced quantities. Many of the practical constraints associated with assessments against the basic restrictions are removed: the E- and H-fields produced by the EUT are evaluated in free space at the corresponding separation distance.

For a given EUT, RF exposure condition, and corresponding separation distance, the SAR-based reference levels should not be exceeded. An assessment against the basic restrictions shall be performed for the EUT when SAR-based reference levels are exceeded.

Measurement of the incident field strengths is the preferred method when assessing against the reference levels, provided that suitable field probes and test equipment are available.

When incident field measurements are not feasible, either due to physical constraints or the availability of suitable field probes and test equipment, the field levels may instead be evaluated computationally. Computational assessment methods are described in RSS-102.SAR.SIM (currently in development).

B.2.3 Special considerations for whole-body exposure

The special considerations for whole-body exposure shall be in accordance with section 4.4.3 of RSS-102.NS.MEAS.

B.2.4 Special considerations for localized exposure

The special considerations for localized exposure shall be in accordance with section 4.4.4 of RSS-102.NS.MEAS.

B.3 Test set-up

The test set-up for SAR-based measurements from 100 kHz to 4 MHz shall be in accordance with the test set-up employed for NS measurements as outlined in section 5.3 of RSS-102.NS.MEAS.

B.4 Measurement procedure

The following sections outline frequency- and time-domain assessment procedures.

B.4.1 Frequency-domain assessments

SAR-based frequency domain measurements from 100 kHz to 4 MHz shall be in accordance with sections 5.4.1 and 5.4.2 of RSS-102.NS.MEAS.

The SAR-based reference levels apply to the maximum time-averaged root mean square (RMS) E- and H-fields observed over any 6-minute period. Consequently, the impact of a 6-minute rolling time-average shall be considered in the assessment. This may be achieved by applying the time-averaging operation to each frequency component and capturing the worst-case SAR-based exposure ratio (ER), or, with sufficient rationale, via calculated scaling factors based on the nature of the transmit waveforms.

Let Eavg (f) and Havg (f) denote the maximum time-averaged RMS E- and H-field levels associated with each frequency component, respectively. As in section 5.4.2.2 of RSS-102.NS.MEAS, the frequency components considered in the assessment may be limited to those for which the field levels exceed the corresponding sensitivity levels specified in section 5.3.5.1 of RSS-102.NS.MEAS.

When computing the SAR-based ER, E- and H-field contributions occurring at the same frequency need not be added together; only the highest contributor is considered. Consequently, the SAR-based ER, denoted by ERSAR-RL, can be expressed as:

\( ER_{SAR-RL}= ∑_{m=1}^M \bigg\{\begin{matrix} \left[ \frac{H_{avg} (f_m)}{H_{SAR-RL} (f_m)} \right]^2 & f_m \lt f_{min,E} \\ max \left[ \left( \frac{H_{avg} (f_m)}{H_{SAR-RL} (f_m)} \right)^2 , \left( \frac{E_{avg} (f_m)}{E_{SAR-RL} (f_m)} \right)^2 \right] & f_m \ge f_{min,E} \end{matrix} \)   (1)

where:

  • M is the total number of frequency components the field levels are within the probe sensitivity range
  • fm is the frequency of the m-th component
  • HSAR-RL and ESAR-RL are the SAR-based reference levels for the incident E- and H-fields, respectively
  • fmin,E is the minimum frequency for which ESAR-RL is defined (see section 5.3.4 of RSS-102.NS.MEAS)

Refer to section 8.2 of RSS-102, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands), for additional guidance.

B.4.2 Time-domain assessments

SAR-based time-domain measurements from 100 kHz to 4 MHz shall be in accordance with sections 5.4.1 and 5.4.3 of RSS-102.NS.MEAS.

Additional care must be taken when performing a time-domain assessment against the SAR-based reference levels, as they apply to the maximum time-averaged RMS E- and H-fields observed over any 6-minute period, and they are frequency dependent. An approach to achieve this is presented in annex H; however, in some cases, other solutions may be more practical. To propose an alternative approach that is equally or more conservative, an inquiry shall be submitted to ISED.

B.5 Total exposure

Compliance with the limits to prevent thermal effects is demonstrated if the worst-case total exposure ratio (TER) corresponding to the effect for all contributors is less than or equal to 1. NS- and SAR-based TERs are evaluated separately. Refer to section 8 of RSS-102 for details.

Annex C: Bystander exposure from laptop computers (normative)

The content of this annex was previously published in Supplementary Procedure SPR-001.

C.1 General

This annex provides information on the requirements and method to perform specific absorption rate (SAR) evaluation with regard to bystanders for laptop type computers (laptop mode/tablet mode) with antennas built-in on display screens.

Laptop type computers (laptop mode/tablet mode) with antennas built-in on display screens will sometimes have a separation distance of 20 cm or less from bystanders, and are therefore subject to routine SAR evaluation. A statement that a minimum separation distance of 20 cm must be maintained between the bystanders and the device in the manufacturer’s user manual will not suffice.

C.2 Procedure

The following measurement procedure shall be followed.

Unless the side(s)/edge(s) of the laptop type computer (laptop mode/tablet mode) containing the built-in antenna(s) was already tested at the same power level against the flat phantom to account for the user requirements (e.g. antenna in the laptop base), ISED requires SAR measurements to be performed with the side(s)/edge(s) of the display screen containing the built-in antenna(s) pointing towards the flat phantom. The separation distance shall not exceed 25 mm between the device and the flat phantom to show compliance for bystanders. Additional configurations regarding SAR testing for laptop type computers (laptop mode/tablet mode) are not required if the separation distance of 25 mm for bystanders represents the worst-case configuration.

  • If the integrated antenna(s) are located in the back side of the display screen, the back side shall be facing towards the flat phantom at a distance not exceeding 25 mm.
  • If the integrated antenna(s) are installed along the edge(s) of the display screen, the edge(s) shall be facing towards the flat phantom at a distance not exceeding 25 mm.
  • If the integrated antenna(s) are installed at the corner of the display, both edges, as well as the back side shall be tested to ensure that the worst-case configuration is captured.

The bystander requirement can be demonstrated based on the Federal Communications Commission (FCC) knowledge database (KDB) publications 447498 and 616217 (host limitation based on measured SAR level) as follows:

  1. SAR measurement at the module level
  2. SAR measurement with a representative host
  3. SAR measurement with each individual host

Annex D: Laptop computers with antenna(s) in keyboard section (normative)

Unless the exemption limits for routine evaluation in RSS-102, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands), are met, all laptops require specific absorption rate (SAR) evaluation for the bottom surface if the antenna is incorporated in the keyboard section. Furthermore, edge testing may be required depending on the exact location of the antenna within the keyboard section.

D.1 Procedure

SAR evaluations are to be performed on the bottom surface and any edge(s) that would produce the highest SAR values for foreseeable use cases (which may differ from device to device).

For example, consider an antenna that is located 10 mm from the bottom of the keyboard and 4 mm from an edge. For this configuration, the bottom and the edge shall be tested; the edge is likely to produce the highest SAR value.

Note that edge testing can be required even if the antenna distance from the bottom surface is less than the distance to the edge and if it is uncertain that the bottom edge would produce the highest SAR.

Figure D1 shows an example of a laptop computer with antennas installed in the keyboard section. The location of each antenna is clearly shown. The required tests for each antenna for this configuration are:

  • Antenna 1
    • Front edge and bottom side (1 g)
    • Left edge and top side (10 g)
  • Antenna 2
    • Front edge and bottom side (1 g)
    • Right edge and top side (10 g)
  • Antenna 3
    • Left edge (10 g)
    • Bottom side (1 g)
  • Antenna 4
    • Right edge (10 g)
    • Bottom side (1 g)

 

Figure D1: Example of a laptop computer showing locations of antennas in the keyboard section

Description of Figure D1

This figure shows an open laptop that contains 4 antennas on the keyboard section:

  • antenna 1 is located at the bottom left of the keyboard, at the corner of the left and front edges
  • antenna 2 is located at the bottom right of the keyboard, at the corner of the right and front edges
  • antenna 3 is located at the top of the left edge of the keyboard
  • antenna 4 is located at the top of the right edge of the keyboard
 

It is recommended that all edges that may produce a higher SAR be evaluated along with the required bottom surface evaluation if the highest SAR exposure condition is unknown. Engineering judgement and best practices are to be employed to determine foreseeable use cases to determine which edges are to be evaluated along with the bottom surface.

Limb SAR shall be considered for antennas near the edge of the keyboard that may be in direct contact with hands or forearms during normal use (i.e. 10 g SAR is required at the applicable edge(s)). 10 g SAR evaluation is not required for an edge that has already been evaluated for 1 g body SAR.

Annex E: Hand exposure during a voice call (normative)

This annex outlines additional testing requirements to assess hand exposure during a voice call.

E.1 General

To determine if the procedure below is applicable, the following steps shall be performed:

  1. Predict the hand specific absorption rate (SAR) at voice power levels based on interactive hand SAR test results.
    • Interactive hand SAR tests are typically measured at reduced power levels with activated proximity sensors.
    • Predict hand SAR levels based on the power difference between interactive hand use power levels and head power levels.
  2. If the predicted hand SAR at voice power levels are above the hand SAR limits (4 W/kg), the procedure below applies.
  3. If the predicted hand SAR at voice power levels are below the hand SAR limits, the procedure below does not apply.

The procedure in section E.2, below, shall be followed if interactive hand SAR data is not available due to test reductions or any other exemptions from other test procedures accepted by ISED.

E.2 Procedure

A flat phantom shall be used to assess limb SAR (10 g) during a voice call.

While a voice call is routed to earpiece, SAR measurements shall follow section 7.3.2 of IEC/IEEE 62209-1528 and be performed with the equipment under test positioned as follows:

  • placed directly against the flat phantom for the left, right and bottom edges of the device
  • placed within 10 mm of the flat phantom for the back side of the device

The device configuration shall be identical to that employed for head SAR measurements, therefore operating at maximum power and 100% duty cycle (or the maximum duty cycle inherent of the transmission technology or design of the equipment).

Annex F: Portable devices operating in the 6 GHz band (5925-7125 MHz) (normative)

The content of this annex was previously published in Supplementary Procedure SPR‑APD. Furthermore, the content of this annex is mainly harmonized with the IEC’s Publicly Available Specification (PAS) 63446:2022, Conversion method of specific absorption rate to absorbed power density for the assessment of human exposure to radio frequency electromagnetic fields from wireless devices in close proximity to the head and body - Frequency range of 6 GHz to 10 GHz.

F.1 General

This annex sets out the general test methods to be followed when carrying out a specific absorption rate (SAR) and absorbed power density (APD) compliance assessment of portable devices overlapping the 6 GHz frequency band that are subject to RSS-248, Radio Local Area Network (RLAN) Devices Operating in the 5925-7125 MHz Band.

F.2 Certification requirements

The APD assessments for radio local area network (RLAN) devices operating in the 5925-7125 MHz band are based on SAR measurements. To this end, the testing laboratory shall have the RSS-102.SAR.MEAS scope of recognition.

F.3 Radio frequency exposure compliance assessment approach

For RLAN devices operating in the 5925-7125 MHz band, the following requirements apply.

Devices operating less than or equal to 20 cm from a user and/or bystander:

Devices operating at distances greater than 20 cm from a user and/or bystander:

  • shall continue to be tested according to the requirements and procedures set forth in RSS-102

F.4 Preparation of the equipment under test

The preparation of the equipment under test (EUT), including the test positions and configurations, shall be based on RSS-102 and its accepted test procedures incorporated by reference, including IEC/IEEE 62209-1528 and Federal Communications Commission (FCC) knowledge database (KDB) 248227 D01. Some requirements are introduced for the test frequencies and channels in the following section.

F.4.1 Configurations to be tested

The configurations to be tested shall be based on FCC KDB 248227 D01.

The maximum output power, including tune-up tolerance, is used to determine the initial test configuration. When the same maximum power is specified for multiple transmission modes in a frequency band, the initial test configuration shall start with the largest channel bandwidth, lowest order modulation, lowest data rate. The subsequent test configurations, including the test reduction procedures, shall follow the aforementioned FCC KDB.

For APD, the following conversion factors apply for the threshold for test reductions:

  • 0.4 W/kg is equivalent to 25% of the APD limits: 5 W/m2
  • 0.8 W/kg is equivalent to 50% of the APD limits: 10 W/m2
  • 1.2 W/kg is equivalent to 75% of the APD limits: 15 W/m2

When other thresholds are specified in KDBs accepted by ISED, the SAR value in W/kg could be converted to an equivalent APDthreshold following this equation:

\(APD_{threshold}=\frac{SAR_{threshold}}{SAR_{limit}}\cdot APD_{limit}\) (2)

Using the methodology and formula in section 7.2.8 of IEC/IEEE 62209-1528, the minimum number of test frequencies shall be 5, provided the number of possible channels is greater than 5. In all cases and test positions, the channel with the highest power subject to SAR limits and the channel with the highest power subject to APD limits shall be tested. When any part of the lowest channel spans across 6000 MHz, compliance to both the SAR and APD limits shall be demonstrated.

An example of the application is shown in table F1. If the device operates using 80 MHz channels, there are 14 possible channels between 5925 MHz and 7125 MHz. For the purposes of testing, a minimum of 5 test frequencies shall be used. The test frequencies should represent the entire frequency range and be evenly spaced representing the low, middle and high portion of the band.

Table F1: Minimum number of test frequencies required
Channel bandwidth (MHz) Number possible channels Minimum number of test frequencies

320

3

3

160

7

5

80

14

5

40

29

5

20

60

5

Situations where SAR compliance (as per IEC/IEEE 62209-1528 or other procedures accepted by ISED) are at a particular separation distance leading to test reduction shall be carefully examined and documented in the RF exposure technical brief. For instance, per FCC KDB 941225 D07, 1 g SAR at 5 mm is required for devices classified as ultra-mobile personal computer (UMPC). Once compliance is demonstrated under these conditions, 10 g SAR at 0 mm is exempted from testing. However, such exemption does not exist for APD. To determine compliance, the EUT shall be assessed against the following:

  • APD limits at 0 mm
  • 1 g SAR at the prescribed distance of 5 mm

Both of these values shall be documented in the RF exposure technical brief.

For the instance of UMPC described above, it is permitted to test the EUT against the 10 g SAR at 0 mm for completeness; however, consistent with the test reduction principle, this value does not have to be reported.

F.5 Measurements

While SAR assessments have been established for many years, APD assessments are relatively new. In October 2022, the IEC introduced IEC PAS 63446 where the APD may be derived from SAR measurements. As a result, measurement systems capable of assessing SAR may be used to assess APD, provided that they implement algorithms allowing the conversion from SAR to APD (see section F.5.1, below).

F.5.1 Measurement system requirements

APD shall be assessed with a SAR measurement system that complies with all the requirements in RSS-102 and the IEC/IEEE 62209-1528 international standard.

The APD shall be derived from the measured SAR values using the formulas in Compliance Assessment of the Epithelial or Absorbed Power Density Below 10 GHz Using SAR Measurement Systems.

The APD evaluation shall be based on the same measurement procedure as defined in RSS-102 and IEC/IEEE 62209-1528 for SAR but with modifications to the uncertainty evaluation (see section F.7, below) to account for the conversion from SAR to APD.

F.5.2 System validation and system check

The system validation and system check shall continue to be performed as per IEC/IEEE 62209-1528. The numerical SAR target values found in table D.2 of that document shall continue to apply.

F.5.3 System check

For system check, it is acceptable to use the various SAR and APD values from the dipole calibration certificate.

F.5.4 System validation

For system validation, in addition to the target values found in table D.2 of IEC/IEEE 62209-1528, the following target values, as shown in table F2, shall be used for standard dipoles and flat phantoms.

Table F2: System validation target values
Frequency (MHz) 1 g SAR (W/kg) 8 g SAR (W/kg) 10 g SAR (W/kg) 4 cm2 APD (W/m2)
6500 298.4 64.6 52.8 1290
7000 275.0 59.7 47.0 1190

Above 6000 MHz, for successful system validation, in addition to the full 1 g and 10 g validation, step a) of annex A.3.5 of IEC/IEEE 62209-1528 shall be used for the 8 g SAR values, which is equivalent to 4 cm2. In situations where the measurement system does not report the 8 g SAR value, validation may be performed directly against the 4 cm2 APD target value.

F.6 SAR correction

The 10 g SAR correction coefficient found in section 7.8.2 of IEC/IEEE 62209-1528 can also be applied for the 8 g SAR.

F.7 Uncertainty evaluation

Measurement equipment manufacturers shall provide all associated uncertainty components for the conversion of SAR to APD. They shall be added to the uncertainty budget table specified in section 8 of IEC/IEEE 62209-1528. The updated uncertainty budget shall be provided in the RF exposure technical brief submitted to ISED in the certification filing.

F.8 Measurement of devices with multiple antennas or multiple transmitters

When an operational mode is capable of multiple simultaneous transmissions, operating in bands other than the 6 GHz frequency band, this operational mode shall also be tested using procedures outlined in section 8 of RSS-102.

The following is a modification to the exposure ratios (ER) calculated in sections 8.2.2.1 and 8.2.2.2 of RSS-102 for transmitters with operating frequencies that straddle 6000 MHz. It is necessary to perform an assessment against the power density (PD) limits (basic restriction up to 10 GHz and reference levels beyond). The ER for the m-th transmitter is given by:

\[ ER_{PD,m}= \bigg\{ \begin{matrix} max⁡ \left[ \frac{SAR_m }{SAR_{limit}}, \frac{APD_m}{APD_{limit}} \right], & 5925\ MHz \lt f_m \le 10\ GHz \\ \frac{psPD_m}{psPD_{limit,m}}, & 10\ GHz \lt f_m \le 30\ GHz \\ max \left[ \frac{psPD_m}{psPD_{limit,m}},\frac{pPD_m}{pPD_{limit,m}} \right], & f_m \gt 30\ GHz \end{matrix} \]
(3)
 

 

where:

  • SARm is the SAR value for the m-th transmitter/test frequency
  • SARlimit is the basic restriction limit that is applicable to the m-th transmitter/test frequency
  • APDm is the APD value for the m-th transmitter/test frequency
  • APDlimit is the basic restriction limit that is applicable for the m-th transmitter/test frequency
  • psPDm is the peak spatial-average power density (psPD) value for the m-th transmitter
  • psPDlimit,m is the applicable psPD reference level limit for the m-th transmitter
  • fm is the operating frequency of the m-th transmitter
  • pPDm is the spatial peak power density (pPD) value for the m-th transmitter
  • pPDlimit,m is the applicable pPD reference level limit for the m-th transmitter

The remaining ER terms in section 8 of RSS-102 apply without any further modification.

F.9 Radio frequency exposure technical brief

In addition to the requirements set forth in RSS-102, the RF exposure technical brief shall also include the:

  • uncertainty budget calculations as defined in section F.7, above
  • system check values above 6 GHz
  • system validation values above 6 GHz

Annex G: Time-averaged SAR (normative)

This content of this annex was previously published in Supplementary Procedure SPR-004.

G.1 General

This annex sets out the general test methods to be followed when carrying out a radio frequency (RF) exposure compliance assessment of wireless devices implementing device-based time-averaging methods for the management and/or mitigation of specific absorption rate (SAR) in the 4 MHz to 6 GHz frequency band.

The following procedure sets out the general test methods to use in assessing the compliance of final products implementing time-averaged specific absorption rate (TAS) algorithms approved by ISED. A list of approved TAS algorithms can be found on ISED’s website.

The test methods outlined below cannot be used to assess final products for algorithms not found on that list. The test methods are to be used for devices enabled for wireless wide area networks (WWANs) implementing device-based time-averaging methods in the 4 MHz to 6 GHz frequency band intended to be used at 20 cm or less from the user and/or bystander.

Devices enabled for wireless local area networks (WLANs) as well as devices operating above 6 GHz will require additional instructions on test set-up, specific test procedures and/or technical requirements. As such, prior to assessing RF exposure compliance for these devices, an inquiry shall be submitted to ISED’s Certification and Engineering Bureau using the General Inquiry form prior to assessing RF exposure compliance for devices where published guidance is not available. The inquiry shall include sufficient information pertaining to the technology and operation of the device in order for ISED to determine the applicable technical and administrative requirements.

Modules or final products using a TAS algorithm shown in ISED's list of approved TAS algorithms for which detailed procedures are not available, including but not limited to WLAN TAS products, shall continue to be approved on a case-by-case basis by ISED. The TAS approval package shall be sent to ISED at least 10 business days prior to the desired certification date.

G.2 Approach to SAR compliance assessment

SAR limits are defined as specific thresholds averaged over any 6-minute (360-second) reference period in accordance with RSS-102, Radio Frequency (RF) Exposure Compliance of Radiocommunication Apparatus (All Frequency Bands), and Health Canada’s Safety Code 6. Some devices are capable of continuously calculating and limiting their time-averaged output power to preserve battery life, maximize call time and optimize network performance. These devices may employ TAS to provide a more representative assessment of SAR levels a user may be exposed to during normal daily use.

G.2.1 Time-averaging period

For compliance with the SAR limits set forth in Safety Code 6, the following requirements shall be met at all times:

  • a reference period of 6 minutes (360 seconds) shall be used
  • compliance shall be demonstrated over any 360-second time interval (rolling time averaging window)
  • Products using an averaging period that is an integer divisor of 360 will yield similar results as an averaging period of 360 seconds.
  • Products using a different averaging period can be considered on a case-by-case basis with a “penalty” to ensure the TAS implementation yields equivalent or more conservative results than 360 seconds. An inquiry must be submitted to ISED to determine if the proposed averaging period is acceptable and its associated penalty.

G.2.2 Averaging methodology

As per Health Canada’s Technical Guide for Safety Code 6, the arithmetic mean shall be used in averaging SAR to demonstrate compliance with the RF exposure limits.

G.3 Time-averaged specific absorption rate implementation and validation considerations

The following are the criteria that shall be considered for proper validation of TAS implementations.

G.3.1 Key parameters

While the SAR compliance assessment is performed using static power settings, the TAS algorithm is validated using dynamic power settings. Applicants are responsible for characterizing the equipment under test (EUT) and identifying the key parameters of the TAS implementation. As part of this characterization, the tolerance(s) associated with the TAS implementation shall be conservatively assessed, with modular and host contributions taken into account, as well as other considerations, including, but not limited to:

  • the output power measurement and/or estimation accuracy for all modes of operation and across all applicable frequency bands
  • the near-field coupling effects (e.g. the linearity of the output power-to-SAR relationship)
  • tune-up tolerance(s)

The following parameters shall be identified for the TAS implementation:

  • Pmax: The maximum instantaneous output power that the transmitter is capable of producing. For ease of presentation, Pmax is expressed in watts throughout this annex, unless otherwise stated. Internally, the EUT may associate a certain nominal maximum output power level with a given operating state, denoted by Pmax,nom. In the context of this annex, Pmax is obtained by scaling up Pmax,nom in accordance with all applicable tolerances and uncertainties.
  • Plimit: The maximum time-averaged output power specified to ensure SAR compliance for a given EUT operating state. For ease of presentation, Plimit is expressed in watts throughout this annex, unless otherwise stated. Internally, the EUT may associate a certain nominal time-averaged output power limit with a given operating state, denoted by Plimit,nom. In the context of this annex, Plimit is obtained by scaling up Plimit,nom in accordance with all applicable tolerances and uncertainties. This may be expressed as:
    \( P_{limit}=P_{limit,nom}\cdot 10^\left( \frac{u_{limit,dB}}{10} \right) \)   (4)
    where ulimit,dB is the total positive uncertainty or tolerance associated with Plimit,nom, in dB.
  • SARtarget: The maximum 1 g or 10 g peak spatial-averaged SAR (psSAR) target specified to ensure SAR compliance for a given EUT operating state. Its value directly corresponds to Plimit or Pmax, whichever is lower. The SARtarget value shall be defined in such a way that the device remains compliant in simultaneous transmission scenarios.
  • Any other relevant power levels or parameters used by the TAS algorithm (e.g. to switch between power control states).

The applicant shall define all EUT operating states, along with the corresponding values of Pmax, Plimit and SARtarget. In addition, the applicant shall clearly define the mechanisms and sensors used to trigger operating state transitions.

Figure G1 illustrates the output power characteristics of a simple TAS implementation.

Figure G1: Illustration of the output power characteristics of a simple TAS implementation

Description of Figure G1

This figure is a plot illustrating the output power characteristics of a simple TAS implementation. Power in milliwatts (mW) is plotted on the y axis versus time in seconds (s) on the x axis. The axis limits are 0 to 300 mW and 0 to 2000 s, respectively. Four different curves are depicted as follows:

  1. The value Pmax (representing the maximum instantaneous power) is a flat red line at 282.5 mW.
  2. The value Plimit (representing the maximum time-averaged power) is a flat black line at 126 mW.
  3. The value Pinstant (representing the instantaneous power) is a blue pulse train with the following properties:
    1. The power level at 0 s is 0 mW.
    2. The maximum power level is 240 mW.
    3. The minimum power level is 50 mW.
    4. The period of the pulse train is 450 s.
    5. The duty cycle of the pulse train is such that 120 s are spent at the maximum level each period, with the remaining 330 s being spent at the minimum level.
  4. The value Paverage (representing the time-averaged power) is obtained by applying a 360 s rolling time average to the instantaneous power curve. It is depicted as a purple curve with the following behaviour:
    1. From time equals 0 to time equals 360 s, the value climbs as the time-averaging window fills with non-zero values.
    2. For time greater than 360 s, the time-averaged power is periodic, with a period of 450 s, linearly transitioning between minimum and maximum values of about 66 and 113 mW, respectively.
    3. The transitions are linear over time intervals of 90 s, while 30 and 240 s are spent at the minimum and maximum levels, respectively.
 

Although the maximum instantaneous power of 240 mW is higher than the Plimit value of 126 mW, the TAS implementation ensures that the time-averaged power is always below Plimit.

G.3.2 Permitted changes for wireless local area network devices

Devices enabled for WLANs as well as devices operating above 6 GHz require additional instructions on test set-up, specific test procedures and/or technical requirements. An inquiry shall be submitted to ISED’s Certification and Engineering Bureau, using the General Inquiry form prior to assessing RF exposure compliance for these devices. The inquiry shall include sufficient information pertaining to the technology and operation of the device in order for ISED to determine the applicable technical and administrative requirements.

G.3.3 Validation criteria

The TAS implementation shall be validated to ensure that, accurately and consistently, the device-based TAS does not exceed the corresponding SARtarget values. This validation shall be achieved using a calibrated and reproducible measurement set-up.

Figure G2 illustrates a calibrated and reproducible measurement set-up. All tests shall be performed over a sufficient amount of time to ensure that the maximum time-averaged results have been captured. Two or more reference periods may be required to capture the maximum results.

Figure G2: Illustration of a calibrated and reproducible measurement set-up

Description of Figure G2

This figure is a block diagram illustrating a calibrated and reproducible measurement set-up. The user interface consists of a computer (PC) connected by an ethernet cable to a network switch, which is, in turn, connected by ethernet cables to the following test equipment:

  • a base station control PC
  • ports 1 and 2 of a base station simulator, which are configured for 4G LTE and 5G NR (New Radio) operation, respectively
  • two spectrum analyzers or power meters, which enable conducted power measurements for both 4G LTE and 5G NR transmissions

The equipment under test receives output power requests from the base station control PC through a USB connection and adjusts the power levels of its 4G LTE and 5G NR ports accordingly. These ports are connected to ports 1 and 2 of the base station simulator, respectively, using directional couplers. The coupled ports of each directional coupler are connected to a spectrum analyzer or power meter to enable conducted power measurements.

 

In addition to the RF exposure technical brief requirements set forth in RSS-102, a separate TAS validation report shall be provided in accordance with section G.7, below. The report shall clearly identify the pass/fail criteria for each validation step in accordance with the guidance provided in the following sections.

The Plimit,nom values used for TAS validation shall be the same as those used for SAR compliance testing.

The technologies and associated operating states for which Plimit is several dB lower than Pmax (i.e. 2 to 4 dB lower) should be considered for each validation criterion, unless instructions indicate otherwise. Within this subset of configurations, those yielding the highest psSAR results, as per the RF exposure technical brief, should be favoured.

G.3.4 Validation through conducted power and SAR measurements

Conducted power measurements in accordance with the guidance provided below shall be performed to validate all TAS implementations; however, conducted power measurements may not capture the near-field coupling and associated radiating characteristics of the device. In other words, a relative change in conducted power may not always translate into an equivalent change in SAR. As a result, single point SAR measurements shall be performed to validate the TAS algorithm for a reduced number of test cases, as outlined in section G.3.6, below.

G.3.5 Considerations for conducted power measurements

For each of the test cases described in sections G.3.4 to G.3.16, the TAS algorithm shall be validated by demonstrating that the time-averaged conducted power remains less than or equal to Plimit over any complete reference period. The measured instantaneous conducted power at the n-th time step can be written as Pmeas[n]. A complete reference period consists of M time steps:

\( M=\frac{T_{ref}}{T_{meas}} \)   (5)

where Tmeas is the time interval between subsequent power measurements (typically much less than 1 second) and Tref is the reference period, i.e. 360 seconds. The rolling time-averaged conducted power at the n-th time step, Pn, is obtained by summing the current (n-th) and M - 1 previous values of Pmeas, and dividing the result by M. This can be expressed analytically as:

\( P[n]=\frac{1}{M} ∑_{m=0}^{M-1} P_{meas}[n-m] \)   (6)

where m is the index of the rolling time-averaging window. In test cases where Plimit remains constant throughout, the TAS algorithm should be validated by demonstrating that P[n] Plimit for all n, i.e. for every time step associated with the test. Otherwise, Pmeas[n] shall be normalized by Plimit[n] prior to applying the rolling time-average. The normalized, rolling time-averaged conducted power, given by p[n], can be expressed analytically as:

\( p[n]=\frac{1}{M} ∑_{m=0}^{M-1} \frac{P_{meas} [n-m]}{P_{limit} [n-m]} \)   (7)

in which case the TAS algorithm is validated by demonstrating that p[n] ≤ 1 for all n, i.e. for every time step associated with the test.

G.3.6 Considerations for single point SAR measurements

Single point SAR measurements shall be performed to validate the TAS algorithm; however, compared with the requirements for conducted power measurements, fewer test cases are required:

  1. Single point SAR measurements need be performed only for changes in requested power, as described in section G.3.7 to G3.9, below.
  2. To account for linearity, single point SAR measurements shall be performed on each antenna for at least one frequency. If possible, each antenna should be validated using a different frequency.
  3. Single point SAR measurements shall be performed only for configurations involving a single transmitter, i.e. not for simultaneous transmission.

The configurations and operating states selected for single point SAR measurements shall match those selected for conducted power measurements and for SAR compliance assessment. This requirement facilitates the correlation of the single point SAR results with both the conducted power measurements and the psSAR results in the RF exposure technical brief.

SAR measurements shall be performed in accordance with the following requirements to ensure a high level of accuracy and repeatability in the TAS algorithm validation:

  1. Measurements shall be performed in an environment that prevents uncontrolled variations in the link budget over time, i.e. time-varying multipath.
  2. The configuration and positioning of the device shall remain consistent and repeatable throughout the measurement process. This consistency is especially important in situations where the device needs to be configured using test mode software and/or charged in between measurements.
  3. The separation distance for TAS validation shall be the same as the compliance distance.

The following steps shall be applied during single point SAR evaluations:

  1. Determine the location of maximum SAR: With the TAS algorithm disabled and the EUT output power set to Plimit,nom, perform an area scan in accordance with IEC/IEEE 62209-1528 to identify the location of maximum SAR. The remaining measurements shall be performed at this location.
  2. Perform a reference measurement: Perform a single point SAR measurement with the TAS algorithm disabled and the EUT output power set to Plimit,nom. The result can be denoted by pointSARPPlimit.
  3. Perform relative instantaneous measurements: Enable the TAS algorithm and perform the given validation step while measuring the single point SAR. As in section G.3.5, pointSAR[n] is used to denote the single point SAR at the n-th time step.
  4. Perform the TAS evaluation: The instantaneous 1 g or 10 g SAR at the n-th step, denoted by SAR[n], can be expressed as:

\( SAR[n]=\left( \frac{pointSAR[n]}{pointSAR_{Plimit}} \right)\cdot psSAR \)   (8)

where psSAR is the corresponding psSAR value in the RF exposure technical brief. The reference period consists of M time steps, where M is defined in equation 2. As a result, the TAS value at the n-th time step, TAS[n], is given by:

\( TAS[n]=\frac{1}{M} ∑_{m=0}^{M-1} SAR[n-m] \)   (9)

where m is the index of the rolling time-averaging window. The TAS algorithm shall be validated by demonstrating that TAS[n] ≤ psSAR for all n, i.e. for every time step associated with the test.

G.3.7 Changes in requested power

The TAS algorithm shall be validated when the base station requests different power levels to manage the link budget.

Conducted power measurements shall be performed for at least one band per technology. The Plimit value associated with the chosen band should be several dB lower than the corresponding value of Pmax, i.e. 2 to 4 dB lower. Whenever possible, the same band should not be repeated for different technologies. Frequency-division duplexing (FDD) and time-division duplexing (TDD) configurations shall be treated as separate technologies.

In addition to conducted power measurements, single point SAR measurements shall be performed in accordance with section G.3.6.

G.3.8 Start-up test sequences

Two distinct sequences shall be applied to validate the start-up behaviour of the TAS algorithm:

  1. Upon start-up, request a power level of Pmax,nom for a period of at least 400 seconds, followed by 0.5 ∙ Plimit,nom for a period of at least 400 seconds.
  2. Upon start-up, request a power level of 1 mW (0 dBm) for a period of at least 400 seconds, followed by Pmax,nom for a period of at least 400 seconds.

For TDD and time-division multiple access (TDMA), Pmax,nom and Plimit,nom may be expressed as frame-averaged or burst-power levels. Care must be taken to ensure that the requested power levels are interpreted consistently to avoid unintended offsets or discrepancies in the validation results.

G.3.9 Pseudo-random test sequence

A pseudo-random sequence of power requests shall be applied to validate the dynamic behaviour of the TAS algorithm. Each test shall be performed with a unique sequence of 150 independent power requests. These power levels are calculated as follows:

\( P_{req}=P_{max,nom} \left( \frac{P_{limit,nom}}{P_{max,nom}} \right)^x \)   (10)

where Preq is the requested power in watts and x is a random value drawn from the Weibull distribution with shape and scale parameters of 2.0 and 0.8 respectively. These values were chosen to ensure that Preq exceeds Plimit,nom on average, while maintaining a reasonable likelihood that some Preq values will sometimes fall well below Plimit,nom.

The corresponding request durations are given by:

\( T_{req}=2(1+2y) \)   (11)

where Treq is the duration of the power request in seconds and y is a uniformly distributed random value between 0 and 1.

Notes:

  • For TDD and TDMA, Pmax,nom and Plimit,nom may be expressed as frame-averaged or burst-power levels. Care must be taken to ensure that Preq is interpreted consistently to avoid unintended offsets or discrepancies in the validation results.
  • Preq may be converted to dBm, and rounded to the nearest 0.5 dB. In addition, a lower bound may be applied to ensure continuous and reliable communication with the base station, e.g. Preq ≥ 1 mW (0 dBm).
  • Values for x can be generated (e.g. in Microsoft Excel) using the following syntax: =0.8*(-LN(1-RAND()))^0.5.
  • If necessary, Treq may be rounded to the nearest second.
  • Values for y can be generated (e.g. in Microsoft Excel) using the following syntax: =RAND().

Figure G3 illustrates a requested power sequence for Plimit,nom = 100 mW (20 dBm), Pmax,nom = 200 mW (23 dBm) and Preq ≥ 1 mW (0 dBm). The request durations have been rounded to the nearest second. As per section G.5.6, similar plots of Preq versus time shall be included in the TAS validation report, along with tabulated summaries of the Preq and Treq values.

 

Figure G3: Illustration of a requested power sequence for Plimit,nom = 100 mW and Pmax,nom = 200 mW

Description of Figure G3

This figure is a plot illustrating a pseudo-random requested power sequence. Power in milliwatts (mW) is plotted on the y axis versus time in seconds (s) on the x axis. The axis limits are 0 to 250 mW and 0 to 600 s, respectively. Three different curves are depicted as follows:

  1. The nominal value of Pmax is a flat line at 200 mW.
  2. The nominal value of Plimit is a flat line at 100 mW.
  3. The requested power is a curve that is time-varying in accordance with a pseudo-random sequence of 150 requested power levels, where:
    1. the requested power levels range from about 45 to 195 mW, with most requests being above the nominal Plimit value; and
    2. the duration of each request is also random in the range of 2 to 5 s.
 

G.3.10 Antenna switching

Conducted power measurements shall be performed to validate the TAS algorithm in antenna-switching scenarios. Maximum power shall be requested from the EUT throughout the test. The switch between antennas shall occur once the TAS algorithm has reached steady state for the first antenna, and the test shall conclude once the algorithm has reached steady state for the second antenna.

When different Plimit and Pmax values are associated with each transmitting antenna, consideration shall be given to the combinations of antennas and operating state(s) for which the Plimit values are several dB below the corresponding Pmax values, i.e. 2 to 4 dB lower. Of these combinations, the performance of the TAS algorithm shall be validated when the EUT switches from the antenna with the highest Plimit value to that with the lowest.

This requirement may be waived if the same Plimit and Pmax values apply to each antenna and if it can be demonstrated that the performance of the TAS algorithm is not affected by antenna switching. In cases where the requirement is waived, the remaining validation steps may be performed for a single antenna; however, simultaneous transmission shall be considered separately.

G.3.11 Change in operating state

Conducted power measurements shall be performed to validate the TAS algorithm when the EUT changes between operating states with different Plimit values (e.g. when sensors or other mechanisms are used to change operating states). Maximum power shall be requested from the EUT throughout the test. The change in operating state shall occur once the TAS algorithm has reached steady state for the first operating state, and the test shall conclude once the algorithm has reached steady state for the second operating state.

The TAS algorithm shall be validated for the following changes in operating state:

  • among the operating states for which the Plimit values are several dB below the corresponding Pmax values, i.e. 2 to 4 dB lower, changing from one operating state to another with a lower Plimit value
  • if applicable, changing from an operating state for which the TAS algorithm is transparent, i.e. PlimitPmax, to one for which Plimit is several dB below Pmax, i.e. 2 to 4 dB lower

When proximity sensors are used, the energy accumulated prior to the proximity sensors being triggered shall be taken into account. Worst-case exposure (highest SAR) shall be assumed prior to the sensor being triggered, which typically occurs when the user is just beyond the triggering distance.

Implementations where TAS is enabled at the proximity sensor level will continue to be evaluated on a case-by-case basis following the relevant principles outlined in annex G until sufficient data is available for ISED to provide detailed guidance.

G.3.12 Frequency band hand-off or redirect

Conducted power measurements shall be performed to validate the TAS algorithm when the EUT switches between frequency bands with different Plimit values. Maximum power shall be requested from the EUT throughout the test. The change in frequency band shall occur once the TAS algorithm has reached steady state for the first band, and the test shall conclude once the algorithm has reached steady state for the second band.

The TAS algorithm shall be validated for the following changes in frequency band:

  • among the frequency band configurations for which the Plimit values are several dB below the corresponding Pmax values, i.e. 2 to 4 dB lower, changing from one frequency band to another with a lower Plimit value
  • if applicable, changing from a frequency band for which the TAS algorithm is transparent, i.e. PlimitPmax, to one for which Plimit is several dB below Pmax, i.e. 2 to 4 dB lower

G.3.13 Technology hand-off

Conducted power measurements shall be performed to validate the TAS algorithm when the EUT switches between technologies with different Plimit values. Maximum power shall be requested from the EUT throughout the test. The technology hand-off shall occur once the TAS algorithm has reached steady state for the first technology, and the test shall conclude once the algorithm has reached steady state for the second technology.

Among the technology configurations for which the Plimit values are several dB below the corresponding Pmax values, i.e. 2 to 4 dB lower, the test shall consist of changing from one technology to another with a lower Plimit value.

G.3.14 Switching between time division duplexing and frequency division duplexing

Conducted power measurements shall be performed to validate the TAS algorithm when the EUT switches between TDD and FDD configurations with different Plimit values, both of which should be several dB lower than the corresponding Pmax values, i.e. 2 to 4 dB lower. Maximum power shall be requested from the EUT throughout the test. The switch between configurations shall occur once the TAS algorithm has reached steady state for the first configuration, and the test shall conclude once the algorithm has reached steady state for the second configuration.

Pmax and Plimit may be expressed differently for TDD relative to FDD, i.e. as frame-averaged or burst-power levels. Care must be taken to ensure that the power levels are interpreted consistently to avoid unintended offsets or discrepancies in the validation results.

G.3.15 Change in modulation scheme

Conducted power measurements shall be performed to validate the TAS algorithm when the EUT changes between modulation schemes with different Plimit values. For example, measurements would be required to validate a change from a higher order, e.g. 64 QAM (quadrature amplitude modulation), to a lower order, e.g. QPSK (quadrature phase shift keying) and vice versa. Both Plimit values should be several dB lower than the corresponding Pmax values, i.e. 2 to 4 dB lower. Maximum power shall be requested from the EUT throughout the test. The switch between modulation schemes shall occur once the TAS algorithm has reached steady state for the first scheme, and the test shall conclude once the algorithm has reached steady state for the second scheme.

This requirement may be waived if the same Plimit value is applied for all modulation schemes associated with a specific communication technology.

G.3.16 Dropped connection

Conducted power measurements shall be performed to validate the TAS algorithm during dropped connections to ensure the algorithm is able to account for previous connection states. Only one test is required with one of the configurations for which Plimit is 2 to 4 dB below Pmax. Maximum power shall be requested from the EUT throughout the test. The dropped connection shall occur once the TAS algorithm has reached steady state, and the test shall conclude once steady state has been regained after the dropped connection.

G.3.17 TAS validation data re-use and test reduction

ISED may accept data re-use or test reduction within a product line. A product line is defined as a set of products with the same form factor and using the same key RF chipset and TAS algorithm.

G.3.18 Data re-use

Data re-use may be applicable if the following conditions are met:

  1. The initial reference model is certified prior to the variant models. It is also possible for the reference model to be certified in Canada within the same time frame.
  2. Each variant has the same transmit chain (i.e. components and layout) as the reference model.
  3. Each variant has the same output power characteristics (e.g. Pmax, Plimit, tolerances) as the reference model.

If the listed conditions are met, an inquiry shall be submitted to ISED’s Certification and Engineering Bureau, using the General Inquiry form, requesting further guidance for data re-use.

G.3.19 Test reduction

Test reduction may be considered when the data re-use conditions above cannot be met due to a product’s:

  • physical design characteristics
  • modes of operation
  • variants having additional options that would result in different Plimit values (from those of the reference model) for common technologies and frequency bands

If the listed requirements cannot be met, an inquiry shall be submitted to the Certification and Engineering Bureau, using the General Inquiry form, requesting further guidance regarding TAS validation test reduction.

G.4 Uncertainty

In the context of SAR compliance testing, i.e. under static power conditions, the uncertainty budget shall be based on the requirements of IEC/IEEE 62209-1528.

For TAS validation, the uncertainties in both the conducted power and single point SAR measurements should be considered. The corresponding uncertainty budgets should be included in the TAS validation report.

G.5 Testing requirements

The following certification requirements are applicable to TAS implementations.

G.5.1 Laboratory requirements

All testing performed to demonstrate compliance of a radio apparatus with the requirements set forth in RSS-102, including its referenced and accepted normative standards and test procedures, shall be carried out by an ISED-recognized testing laboratory.

It is critical that all device-specific evaluation parameters used for compliance evaluations be assessed by an ISED-recognized test laboratory including, but not limited to:

  • factors and methods used to determine applicable exposure conditions and operational modes
  • proximity or other sensors used for power reduction
  • output power
  • dynamic antenna tuning
  • SAR evaluations

TAS algorithm validations shall also be performed by an ISED-recognized testing laboratory in accordance with section G.3.3, above. In addition, the laboratory shall demonstrate that its personnel has been properly trained and qualified to carry out validations on specific TAS implementations.

For proprietary test procedures and validation protocols that have been accepted by ISED, the recognized test laboratory shall demonstrate that they have been approved by the TAS algorithm developer to assess their technology. An approval letter from the TAS algorithm developer shall be provided in the certification filing. A TAS algorithm developer’s in-house test laboratory is not required to submit an approval letter.

G.5.2 Modular approval

Provided the requirements in Radio Standards Procedure RSP-100, Certification of Radio Apparatus and Broadcasting Equipment, are met, the applicant may obtain approval for a TAS-enabled module intended for installation in a host product. As per section 8.2 of RSP-100, modular approvals are not applicable for small, portable, hand-held and wearable devices with an overall diagonal dimension of less than 20 cm.

Where modular approval is permitted, conducted power measurements should be performed to validate the TAS algorithm at the module level. Where modular approval is not permitted, the measurements shall be performed at the host level.

Single point SAR measurements shall be performed on representative hosts to validate the TAS algorithm. The Class 4 Permissive Change (C4PC) shall be applied to validate each host. ISED shall be notified, and an updated RF exposure technical brief shall be provided.

G.5.3 Requirements for the module

The module manufacturer shall validate the full range of parameters that could be implemented by the host manufacturer.

Module validation shall be performed in accordance with section G.3.3; however, with a sufficient rationale, ISED may consider exclusions based on host-specific implementations, as well as limitations on the operating states and applicable exposure conditions. An inquiry with ISED is required for these exceptions to be considered.

The module integration manual requirement of RSS-102 applies. In addition, for validation steps that are not carried out at the module level, or when the range of TAS parameters implemented within the host fall outside the scope of validations carried out on the module, the requirements in section G.5.4 apply.

G.5.4 Requirements for the host

The host manufacturer shall ensure that the implementation satisfies all of the validation criteria set forth in section G.3.3. Any validation steps that are not carried out at the module level shall be validated at the host level. If the host uses parameters outside of those validated by the module manufacturer, additional testing will be required for proper validation and certification.

G.5.5 Enabling TAS post-certification

For pre-certified modules that did not implement TAS upon original certification, the requirements are as follows when firmware updates are applied to implement TAS:

  1. A Class 3 Permissive Change (C3PC) application shall be submitted for the pre-certified module with the new firmware version identification number (FVIN) of the firmware intended to enable the TAS algorithm.
  2. A Class 4 Permissive Change (C4PC) shall be applied to certify each new host product. A complete RF exposure technical brief and TAS validation report for the new host shall be included in the certification filing.
  3. For existing host products that were certified without the TAS algorithm enabled, a C4PC application shall be submitted prior to enabling the algorithm. A supplemental TAS validation report shall be provided if the RF output power measurement is no different from the one originally listed. Otherwise, RF exposure shall be reassessed, and both an updated RF exposure technical brief and TAS validation report shall be provided.

The TAS validation report shall contain configurations previously evaluated by the TAS algorithm designer/manufacturer, along with any additional host-specific configurations and modes of operation that have not been previously assessed, including, but not limited to:

  • simultaneous transmission
  • additional TAS parameters not already evaluated or characterized
  • change in exposure conditions
  • proximity sensor(s) operating in conjunction with the TAS algorithm
  • other sensors used to determine the exposure condition or mode of operation

G.5.6 Information to provide to ISED

In addition to the reporting requirements set forth in annex A, the information detailed in sections G.6 and G.7, below, shall be provided with the certification filing package sent to ISED:

  • time-averaged specific absorption rate validation checklist
  • information to include in the time-averaged specific absorption rate validation report

G.6 Time-averaged specific absorption rate validation checklist

Table G1 contains a list of tests that shall be performed, provided they are supported by the TAS algorithm, to validate the time-averaged specific absorption rate (TAS) algorithm. The first column shows the type of test to be performed; in the second column, the result of the test is to be added in the empty cell next to each test; and, if a test was not performed, a reason to justify the omission of that test is to be added in the corresponding empty cell of the third column.

Table G1: TAS validation checklist
TAS algorithm validation test

Test result
(pass, fail, n/a)

Justification for omission of test

Changes in requested power

 

 

Antenna switching

 

 

Change in operating state

 

 

Frequency band hand-off or redirect

 

 

Technology hand-off

 

 

Switching between TDD and FDD configurations

 

 

Change in modulation scheme

 

 

Dropped connection

 

 

G.7 Information to include in the time-averaged specific absorption rate validation report

This section contains a list of items to be provided in the time-averaged specific absorption rate (TAS) validation report, which shall be submitted as part of the certification filing.

1. General information

  1. Test laboratory information, including ISED recognition and accreditation information
  2. Evaluation dates
  3. General description of the device, including information related to certification, i.e. ISED certification number, hardware version identification number (HVIN), product marketing name (PMN), host marketing name (HMN), etc.
  4. Brief description of the TAS implementation, including the model number (of the chipset and/or module, if different from the model number of the host device) and TAS version number

2. Validation test procedure, operating configurations and test conditions

  1. Detailed description of all key parameters identified in section G.3.1, above
  2. Description of the set-up and procedures for conducted power and single point SAR measurements
  3. SAR measurement system check and dielectric parameter measurement results (when different from those provided in the RF exposure technical brief)
  4. Description of all applicable TAS operating states and configurations, as well as the selection criteria used to satisfy all test considerations detailed in section G.3.2
  5. Plimit and Pmax values for all operating states and configurations selected for validation testing
  6. Description of the pass/fail criteria established for each validation step
  7. Summary of the TAS validation criteria evaluated, i.e. a copy of the checklist from section G.6

3. Test results

  1. Tabulated summary of the test results including a clear determination of the pass/fail results
  2. Tabulated summary of Preq and Treq values generated for the pseudo-random test sequence described in section G.3.9, along with plots of Preq versus time
  3. Test plots for each validation criterion that demonstrate that the established thresholds have been adhered to, where each shall clearly indicate if normalization has been applied and shall display the following:
    1. The rolling time-averaged conducted power and SAR (if applicable)
    2. The instantaneous conducted power and SAR (if applicable)
    3. The power requested by the base station simulator
    4. All applicable reference lines, such as those corresponding to Plimit and Pmax for conducted power measurements and psSAR for single point SAR measurements
    5. The maximum time-averaged conducted power; or, if applicable, TAS value observed
    6. Any other information necessary to demonstrate that the algorithm is functioning as intended and correlation with the compliance assessment results has been clearly established

4. Uncertainty budget

  1. Uncertainty components associated with the conducted power and single point SAR measurements

Annex H: Additional requirements for measurement-based, time-domain assessments against the SAR-based reference levels

This annex provides additional requirements for measurement-based, time-domain assessments against the specific absorption rate (SAR)-based reference levels.

H.1 Assessment overview

The proposed procedure for evaluating the SAR-based exposure ratio (ER) can be summarized as follows:

  1. Apply a sliding Fast Fourier Transform (FFT) to H(t) and E(t), the measured H- and E-field vector magnitudes. Provided that considerations such as aliasing, truncation/spectral leakage and scaling are properly addressed, the root mean square (RMS) amplitude spectra associated with H(t) and E(t) can be obtained for the time interval over which the FFT was applied.
  2. For each set of spectra, isolate the frequency range associated with the assessment, and evaluate the ER corresponding to that time interval.
  3. Apply a rolling 6-minute average to these ERs, to yield the SAR-based ER for the emission(s) under consideration.

H.2 Fast Fourier Transform requirements

The following shall be considered when applying a sliding K-point FFT to H(t) and E(t):

  1. The time interval over which each FFT is performed, denoted by \(T_w\), shall be large enough to ensure sufficient frequency resolution for the assessment. A condition similar to \( T_w \ge 100\sqrt{f_{low} f_{high}}\) is recommended, where \(f_{low}\) and \(f_{high}\) are the lowest and highest frequencies associated with the assessment, respectively.
  2. The sampling frequency, denoted by \(f_s\), shall be high enough to prevent aliasing and foldover effects, i.e. more than twice the highest frequency associated with the assessment. A condition similar to \(f_s ≥ 2(f_{high}+f_{low})\) is recommended.
  3. The number of time samples associated with the FFT is given by \(N=\lfloor f_s T_w \rfloor\), where \(\lfloor*\rfloor\) denotes the “floor” or “round down” operation. The condition \(K≥N\) shall be met. It is recommended that K be the next power of 2 relative to N.
  4. The effects of truncation and spectral leakage shall be prevented. Scaling the time samples by the Hann window is recommended for this purpose.
  5. The time interval between successive FFT evaluations, denoted by \(T_{slide}\), shall be small enough to ensure the dynamics of the measured fields are fully and continuously captured. It is recommend to have \(T_{slide}≤0.1T_w\) if the Hann window is being applied.

H.3 Isolating the assessment frequency range and Fast Fourier Transform scaling

Let \(H_w [k]\) and \(E_w [k]\) denote the discrete spectra obtained via K-point FFT of H(t) and E(t) over the most recent time interval \(T_w\), where k is the frequency index. The frequency range associated with the \(H_w [k]\) and \(E_w [k]\) extends from 0 Hz to \(f_s\), with \(f_s/2\) to \(f_s\) representing negative frequency content. As the assessment is performed over a limited frequency range (e.g. 100 kHz to 10 MHz), the corresponding values of k need to be identified. The frequency corresponding to the k-th sample, denoted by \(f_k\), can be expressed as:

\( f_k=\frac{(k-1)}{K} f_s \)   (12)

allowing k to be mapped to frequency. Let \(k_{min,H}\) and \(k_{min,E}\) denote minimum values of k for which \(f_k\) is within the H- and E-field assessment frequency ranges, respectively. Similarly, let \(k_{max}\) denote the maximum value of k for which \(f_k≤f_{high}\).

For the assessment frequency ranges, the RMS magnitude spectra associated with \(H_w [k]\) and \(E_w [k]\), denoted by \(H_{w,rms} [k]\) and \(E_{w,rms} [k]\), can be expressed as:

\( H_{w,rms} [k]=\frac{\sqrt{2}}{aN} |H_w [k]| \)    (13)

and

\( E_{w,rms} [k]=\frac{\sqrt{2}}{aN} |E_w [k]| \)    (14)

where a is the window scaling factor, e.g. a=0.5 for the Hann window.

H.4 Evaluating the SAR-based exposure ratio

The SAR-based exposure ratio (ER) associated with the time interval (\(T_w\)) over which the most recent FFT was performed, denoted by \(ER_{SAR-RL,w}\), can be expressed as:

\( ER_{SAR-RL,w}=\frac{N}{K} ∑_{k=k_{min,H}}^{k=k_{max}} \bigg\{\begin{matrix} \left( \frac{H_{w,rms}[k]}{H_{SAR-RL}[f_k]} \right)^2 & k \lt k_{min,E} \\ max \left[ \left( \frac{H_{w,rms}[k]}{H_{SAR-RL}[f_k]} \right)^2,\left( \frac{E_{w,rms}[k]}{E_{SAR-RL}[f_k]} \right)^2 \right] & k \ge k_{min,E} \end{matrix} \)    (15)

where \(H_{SAR-RL} [f_k]\) and \(E_{SAR-RL} [f_k]\) are the values of the SAR-based H- and E-field reference levels at \(f_k\), respectively.

The SAR-based ER associated with the assessment, \(ER_{SAR-RL}\), is given by applying a rolling 6-minute time-average to \(ER_{SAR-RL,w}\), and identifying the maximum value over any 6-minute period.