Eurofins Product Testing - OTA
The new test methods and performance criteria for over-the-air (OTA) testing of handheld wireless devices with a head phantom (SAM) and free space measurements for radio modems are mandatory in the US. The US based PTCRB provides a framework for mobile equipment type certification. This includes the definition of the test specification and methods to implement the type certification process for mobile equipment. These requirements became mandatory for mobile equipment used with most of US wireless carriers. Recognized OTA measurement facilities must be authorized by the CTIA (Cellular Telephone Industries Association )Certification Program. In Europe OTAis GCF required since October 2008.
Good radiated performance is critical to the operation of a mobile station in today's networks. As devices become smaller, radiated performance can often become compromised. For example, achieving an efficient antenna in a small size and over both cellular and PCS (Personal Communication Systems) frequency bands is a difficult task. A comprehensive and accurate characterization of radiated performance will enable carriers and manufacturers to determine how well mobile stations will work within the constraints of a specific cellular network design. OTA tests are based on spherical pattern measurements.
Generally, peak EIRP (Effective Isotropic Radiated Power) is not a good indication of mobile performance in the field. For example, if the radiation pattern of the mobile station's antenna system is highly directive, the peak EIRP would be high (since the antenna gain is high in one direction), but coverage would be poor in other directions. In a cellular environment it is best to maximize the spatial coverage of the antenna system so that the user does not have to point the antenna in one particular direction to get good call performance. Further, the human head can alter the shape and peak value of the EUT radiation pattern. Losses due to the head can vary significantly with frequency, device size, and the antenna design implemented. From a field performance perspective, measurement of the average and peak EIRP on a head model is more meaningful than measurement of peak EIRP in free-space conditions. Besides the EIRP evaluation the mobile transmit power given in a 3-D antenna pattern is defined by further test parameters as the Total Radiated Power (TRP), the Near-Horizon Partial Radiated Power (NHPRP), Directivity, Gain, etc.) Phantom OTA tests are NOT radiation absorption, hazard or health and safety tests. It is only intended to determine blocking effect of human head pattern. Head and body absorption tests are part of the SAR (Specific Absorption Rate) evaluation.
Receiver performance is equally important to the overall system performance, as is transmitter performance. The downlink, or subscriber unit receive path is integral to the quality of the device's operation. Poor receiver radiated performance will cause the user of the subscriber unit to hear a low quality voice signal. This can also cause the subscriber unit to lose the base station signal resulting in abrupt termination of the call.
The receiver sensitivity is tested according to the CTIA Certification Program for a mobile receiver loopback test. It comprises measurements to determine the minimum received power required to achieve the specified bit error rate at each position, the Effective Isotropic Sensitivity (EIS), the Total Isotropic Sensitivity (TIS) and the Near-Horizon Partial Isotropic Sensitivity (NHPIS).
For further information on our OTA testing capabilities, please contact our national organisations or our specialists or get in touch directly with our wireless radio and mobile communication experts:
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