OTA TIS – RED / ETSI / FCC

What Is OTA TIS — RED?

TIS (Total Isotropic Sensitivity) shows how weak a signal the device, together with its antenna, can receive at an acceptable error rate. Sensitivity is measured at points on the sphere and reduced to a single value. It is the receiver-side counterpart of TRP.

Purpose of OTA TIS — RED

The purpose is to measure the device's actual performance at the edge of coverage. Even if TRP is good, if TIS is poor the device sends a signal but cannot receive what comes back; the user experiences this as dropped connections.

Which Products Is OTA TIS — RED Applied To?

Smartphones and tablets
IoT and LPWAN devices
Automotive telematics units
Wireless payment and metering devices
Wearable devices

In Which Sectors Is OTA TIS — RED Used?

TelecommunicationsElectronicsAutomotiveMedical Device

Standards Related to OTA TIS — RED

REDEU radio equipment directive test
ETSIEuropean telecommunications standards test
FCCUS radio and EMC regulations test

OTA TIS — RED Conditions

Environment: Anechoic room or verified reverberation room
Screening: Sensitivity measurement on spherical angle grid
criterion: Lowest achievable level at defined error rate (BER/BLER) threshold
Cihaz konumu: Free space and with phantoms if necessary

Equipment for OTA TIS — RED

Anechoic chamber and positioner system
Communication test set (signal generator and error-rate measurement)
Measurement antennas and a calibrated RF chain
Head and hand phantoms

Sample Requirements for OTA TIS — RED

The sample must be taken so as to represent the batch or production run.
Sample description, material type, and production direction if any, must be stated.
The standard to be applied and any customer specification must be provided together with the sample.
The test may be destructive; the required number of samples must be confirmed in advance.
Surfaces that will be tested must be protected during transport.

Duration of OTA TIS — RED

TIS measurement takes longer than TRP: at each angular point, the signal level is stepped down to find the threshold. The study takes days.

OTA TIS — RED Procedure

1The device is placed on the positioner and communication established.
2The measurement chain is calibrated.
3The signal level is stepped down at each angular point.
4The level at which the defined error-rate threshold is reached is recorded.
5TIS is calculated by combining the values over the sphere.
6Repeated with phantom configurations if required.
7Results are reported per band and channel.

OTA TIS — RED Acceptance Criteria

The method standard defines how the test is performed, not what the result must be. The acceptance limit comes from the material or product standard, the customer specification, or the relevant regulation; this page therefore does not give a numerical limit.

Evaluation of Results

The result is given as TIS values per band and channel; a lower value means better sensitivity. The acceptance threshold generally comes from an operator acceptance specification. The device's own noise sources (display, camera, power circuits) can noticeably degrade TIS; this effect shows up in the measurement.

OTA TIS — RED Report

Sample description, material/product information, and batch number if any
Sample preparation method and conditioning conditions
Standard and test conditions applied
Instrument used and calibration status
Measurement results and units
Measurement uncertainty (if requested)
A statement that the result applies only to the specimen submitted for testing

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 authorisations

Related Regulations

Harmonised standards applied according to the product family
EU 765/2008 (market surveillance and accreditation framework)
Relevant product regulations and customer specifications

RF and Wireless Testing — What Does This Testing Field Cover?

The section below describes the field that the OTA TIS 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 OTA TIS — RED

Why does TIS take longer than TRP?

In TRP a single power reading is taken at each point. In TIS a threshold is sought at each point: the signal is stepped down and error rate measured. This means far more measurements per point.

Does the device's own noise affect the result?

Yes, it is often the dominant factor. High-speed interfaces and display drivers couple noise into the receive band, degrading sensitivity; this is an issue that must be addressed at the design stage.