OTA Evaluation of Mobile Phone Antenna Performance for VoLTE [Measurements Corner]

This article compares the over-the-air (OTA) performance of tradit ional voice service and voice-over LTE (VoLTE). We present the results of the OTA measurements of the antenna performance of 22 mobile phones commonly used over the last two years. VoLTE is a feature included in LTE that allows voice service to be delivered as data flows. Traditional studies on LTE include only data service and, therefore, OTA for data service, which is measured with the phone held in the browsing position only by the hand, whereas VoLTE uses the same data channel but with the device held next to the head by a hand. Traditional studies on voice service include only OTA in voice service. The figures of merit (FoMs) taken into account for ranking the devices were the total radiated power (TRP) and the total isotropic sensitivity (TIS), which are related to the transmitter and receiver antenna performance, respectively. Our investigation includes results for talk mode using left- and right-hand phantoms next to the head to calculate the maximum power radiated by the transmitter. To evaluate the sensitivity of the receiver, we considered the performance in talk mode using a right-hand phantom next to the head as well as in data mode using only the hand phantom.