OTA Testing — CTIA OTA Testing Plan / 3GPP TR 37.977

What Is OTA?

OTA (over-the-air) test is where the device as a whole, including the antenna, is measured by spherical scanning in a reflection-free room; This is the experimental group in which quantities such as total emitted power, total isotropic sensitivity and MIMO performance are determined.

Purpose of OTA

The purpose is to determine the actual performance of the device, including antenna and body effects, and to verify that it meets operator acceptance requirements.

Which Products Is OTA Applied To?

Smartphones and tablets
Cellular modules and CPE devices
In-car telematics units
Wearable devices

In Which Sectors Is OTA Used?

TelecommunicationsElectronicsSoftwareCyber Security

Standards Related to OTA

CTIA OTA Test Plan
3GPP TR 37.977 (MIMO OTA)
3GPP TS 38.521-2 (FR2 OTA)
IEEE Std 149

OTA Conditions

Quantities measured: Total radiated power (TRP), total isotropic sensitivity (TIS), MIMO throughput
Environment: Reflective room; global angle scan
Senaryolar: Free space, next to the head phantom, handholding scenarios
Frequency: Bands declared by the device

Equipment for OTA

Anti-glare OTA measuring chamber and global positioner
network emulator
Calibrated measuring antenna set and reference dipoles
Head and hand phantoms

Sample Requirements for OTA

The device must be in final configuration and fully charged
Use scenarios and holding positions must be defined
The device must be able to transmit and receive continuously
Final production software must be used

Duration of OTA

Typically 2–4 weeks depending on the number of tapes and scripts.

OTA Procedure

1The device is installed on the locator.
2The network connection is established.
3With global scanning, the emitted power is measured and TRP is calculated.
4TIS is calculated by sensitivity scanning.
5Phantom scenarios recur.
6The results are compared to operator requirements.

OTA Acceptance Criteria

Acceptance criteria are given as TRP and TIS minimum values in operator acceptance plans or customer specifications.

Evaluation of Results

OTA results are strongly dependent on stem and retention effects; Free space measurement alone does not represent field performance. The validity of the measurement depends on room calibration and positioner accuracy.

OTA Report

Implemented test plan
Device and software description
Measuring environment and calibration
Scenario wise TRP and TIS results
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 authorisations

Related Regulations

Operator acceptance programs (CTIA, GCF, PTCRB)

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

The section below describes the field that the OTA 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

According to which standard is OTA made?

OTA is executed in scope CTIA OTA Test Plan, 3GPP TR 37.977 (MIMO OTA), 3GPP TS 38.521-2 (FR2 OTA) and IEEE Std 149. 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 OTA apply to?

Mainly applied to Smartphones and tablets, Cellular modules and CPE devices, In-car telematics units and Wearable devices. Whether your product is included in the scope is determined by examining its technical specifications and intended use.

Under what conditions is OTA done?

The determining parameters are: Quantities measured — Total radiated power (TRP), total isotropic sensitivity (TIS), MIMO throughput, Environment — Reflective room; global angle scan and Senaryolar — Free space, next to the head phantom, handholding scenarios. 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 OTA?

The device must be in final configuration and fully charged, Use scenarios and holding positions must be defined and The device must be able to transmit and receive continuously. The number of samples is determined according to the product standard and the scope to be reported.

How long does OTA take?

Typically 2–4 weeks depending on the number of tapes and scripts. 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 OTA result called "appropriate"?

Acceptance criteria are given as TRP and TIS minimum values in operator acceptance plans or customer specifications.