Total Radiated Power (TRP) Implications for a GSM Power Amplifier

As Over-the-Air (OTA) testing is becoming standardized and is being adopted by network providers, more pressure is being exerted on the RF engine in a mobile device to improve its performance in real-world scenarios. No formal specifications have been standardized as of yet for the performance results of a mobile device that has undergone OTA testing.

However, the Cellular Telecommunications Industry Association (CTIA) has established the methods for OTA testing and some network providers have set their own specifications. OTA testing methods that are used to test a mobile device will be discussed with the concentration being on the performance parameter that more closely relates to the power amplifier (PA) in a GSM (Global System for Mobile Communications) system, the Total Radiated Power (TRP).

A method of testing which presents conditions to the PA that closely imitate the conditions presented during OTA testing is also discussed. This allows the TRP performance of the PA to be evaluated. Test results from two GSM PA modules are presented and compared, one being TRP compliant and the other being non-compliant.