What Is Occupied Bandwidth — RED?
The occupied bandwidth measurement is the measurement of the frequency range containing the standard-defined percentage (typically 99%) of the total radiated power of the transmitter, or the width between edges falling within a defined level.
Purpose of Occupied Bandwidth — RED
The purpose is to verify that the signal remains within the allocated channel or band limits.
Which Products Is Occupied Bandwidth — RED Applied To?
- Wi-Fi and Bluetooth transmitters
- Short range devices
- cellular modules
- Digital modulation transmitters
In Which Sectors Is Occupied Bandwidth — RED Used?
Standards Related to Occupied Bandwidth — RED
- REDEU radio equipment directive test
- ETSIEuropean telecommunications standards test
- FCCUS radio and EMC regulations test
Occupied Bandwidth — RED Conditions
- Definition
- Band containing standard-defined percentage of total power (e.g. 99% power bandwidth)
- Alternative measurement
- Interedge width falling at a defined level (e.g. −26 dB)
- Measurement settings
- Detector with standard defined resolution and video bandwidth
- Configuration
- The modulation and data rate that gives the widest bandwidth are selected
Equipment for Occupied Bandwidth — RED
- Spectrum analyzer (with power bandwidth function)
- Device test mode control interface
- Calibrated cable and attenuator set
- Semi-reflective room (for diffuse measurement)
Sample Requirements for Occupied Bandwidth — RED
- The device should be driven in the widest bandwidth configuration
- Measurement settings must comply with the standard
- Channel selection should include lower, middle and upper channels
- Final production software must be used
Duration of Occupied Bandwidth — RED
Days by number of channels and modes.
Occupied Bandwidth — RED Procedure
- 1The configuration that provides the widest bandwidth is selected.
- 2Measurement settings are configured according to the standard.
- 3Measurements are made in the lower, middle and upper channels.
- 4The occupied bandwidth is calculated.
- 5The results are compared to the band limits.
Occupied Bandwidth — RED Acceptance Criteria
The acceptance criterion is that the signal remains within the allowed channel or band limits; can give standard maximum bandwidth.
Evaluation of Results
Measurement settings and detector selection change the result. If measurements are made in the narrowest band configuration, the worst case will be undocumented.
Occupied Bandwidth — RED Report
- Applied standard and definition
- Device configuration
- Measurement settings
- Bandwidth results by channel
- Measurement uncertainty
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Radio Equipment Directive 2014/53/EU (RED)
- FCC Part 15
RF and Wireless Testing — What Does This Testing Field Cover?
The section below describes the field that the Occupied Bandwidth test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
RF and wireless testing shows that a device containing a radio uses the spectrum correctly and operates within the limits the relevant legislation allows. This family is a separate body of work from EMC: EMC addresses unwanted interference, whereas here INTENTIONAL emission is assessed.
Spectrum is a public and limited resource, and this determines the legal character of the field. A device spilling outside its permitted band or emitting excess power is not merely a technical defect but a violation that disrupts someone else's service. Radio conformity is therefore policed more strictly than other test fields and markets maintain their own national regimes.
Measurements run separately on the transmitter and receiver sides. On the transmitter side, output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power and the power envelope are measured. On the receiver side, sensitivity, selectivity, blocking and spurious response rejection are assessed. The receiver side is often neglected, but in some bands it is a regulatory requirement.
Access protocol specific behaviours are a third axis: listen before talk (LBT), duty cycle, dynamic frequency selection (DFS) and transmit power control (TPC). These mechanisms enable spectrum sharing and it must be shown that they work correctly.
HUMAN EXPOSURE is the fourth axis and one of the most commercially critical. For devices used close to the body, SAR (specific absorption rate) is measured; for devices used at a distance, a field strength assessment is made. Limits and measurement methods vary by market; the same device is assessed separately for Europe and the United States.
Market regimes are decisive in this family and do not substitute for one another: the Radio Equipment Directive and ETSI harmonised standards in Europe, FCC authorisation in the United States (through a TCB for intentional radiators), ISED in Canada, MIC in Japan, KC in South Korea and SRRC in China each carry their own set of requirements. The same device requires a separate file for each market, and some markets impose a local representative or local testing requirement.
Module integration is the subject that raises the most questions in the field. Using a certified radio module does not automatically make the device compliant. A module certificate is valid for a defined antenna, a defined supply and defined conditions of use; if the antenna changes, the layout changes or the module is operated at a different power level, reassessment is required.
The presence of several radios in the same device (Wi-Fi + Bluetooth + cellular + NFC) gives rise to a simultaneous transmission assessment: SAR and unwanted emission measurements are made for the worst case in which the radios operate together.
Method groups in this field
Transmitter measurements
Output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power, power spectral density.
Receiver measurements
Sensitivity, selectivity, blocking, spurious response rejection.
Spectrum sharing mechanisms
Verification of listen before talk, duty cycle, dynamic frequency selection and transmit power control.
Human exposure
SAR measurement (handheld and body-worn devices), field strength assessment, multi-radio scenarios.
Protocol conformity
Cellular network conformity testing, Bluetooth and Wi-Fi certification testing, GNSS performance.
Antenna measurements
Gain, radiation pattern, efficiency and total radiated power (TRP) measurements.
Commonly confused in this field
- Using a certified module does not automatically make the device compliant; if the antenna, layout or power level changes, reassessment is required.
- An FCC file does not replace a CE file; each market operates its own regime.
- Receiver side measurements are a regulatory requirement in some bands; measuring only the transmitter produces an incomplete file.
- SAR limits and measurement methods differ by market; a result in one market does not carry over to another.
- For devices carrying several radios the simultaneous transmission scenario must be assessed; measuring them individually is not sufficient.
- Some markets impose local testing or a local representative requirement; technical conformity alone does not secure market access.
Which decisions these results support
- Market access under radio equipment legislation
- Verification of the antenna and RF front end design
- SAR and RF exposure conformity
- Verification of module integration and the scope of reassessment
- Determining the worst case in multi-radio scenarios
Related Tests
Frequently Asked Questions About Occupied Bandwidth — RED
According to which standard is Occupied Bandwidth made?
Occupied Bandwidth is executed in scope Bandwidth sections of ETSI radio standards, FCC Part 15, ITU-R SM.328 (occupied bandwidth definition), RED, ETSI and FCC. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Occupied Bandwidth apply to?
Mainly applied to Wi-Fi and Bluetooth transmitters, Short range devices, cellular modules and Digital modulation transmitters. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Occupied Bandwidth done?
The determining parameters are: Definition — Band containing standard-defined percentage of total power (e.g. 99% power bandwidth), Alternative measurement — Interedge width falling at a defined level (e.g. −26 dB) and Measurement settings — Detector with standard defined resolution and video bandwidth. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Occupied Bandwidth?
The device should be driven in the widest bandwidth configuration, Measurement settings must comply with the standard and Channel selection should include lower, middle and upper channels. The number of samples is determined according to the product standard and the scope to be reported.
How long does Occupied Bandwidth take?
Days by number of channels and modes. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Occupied Bandwidth result called "appropriate"?
The acceptance criterion is that the signal remains within the allowed channel or band limits; can give standard maximum bandwidth.