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

Abstract

Abstract-This paper compares Over-The-Air (OTA) performance of traditional voice service and Voice over LTE (VoLTE). The results of the OTA measurements of the antenna performance of 22 mobile phones commonly used over the last two years are presented. VoLTE is a feature included into LTE which allows voice service to be delivered as data flows. Traditional investigations for LTE only include data service and therefore OTA for data services which is measured with the phone held in browsing position by the hand only, whereas the VoLTE uses the same data channel but in a position next to the head held by a hand. Traditional investigations of voice service only include voice service and OTA in voice service. The Figures of Merit (FoMs) taken into account for the ranking of the devices are the Total Radiated Power (TRP) and the Total Isotropic Sensitivity (TIS), related respectively to the transmitter and receiver antennas performance. The investigation includes results for talk mode using left and right hand phantoms next to head to calculate the maximum power radiated by the transmitter. To evaluate the sensitivity of the receiver, performances in talk mode using right hand phantom next to head as well as in data mode using only the hand phantom were considered. The results show a variation in TRP from 9 dB to 17 dB and approximately 9 dB spread in TIS among the phone models in the European LTE bands analyzed. Up to 8 dB difference in TRP between right and left hand usage were found for the worst performing phones, whereas their performances in free space are the same as the best performing phones. Key parameters of our analysis are accuracy, repeatability and testing time, since the equipment and the measurement procedure follow the CTIA Specification.

Over-the-Air Evaluation of the Antenna Performance of Popular Mobile Phones

“…The spread is: 1) at low frequencies up to 16 dB for BHHR and up to 18 dB for BHHL; and 2) at high frequencies up to 14 dB for BHHR and up to 10 dB for BHHL. It should be mentioned that at low frequencies the maximum variation is larger than what has been seen before [18], [19], [21], [22]. At high frequencies the maximum spread is larger compared to what has been found in [18], but smaller than the one presented in [19], [21], [22].…”

“…It should be mentioned that at low frequencies the maximum variation is larger than what has been seen before [18], [19], [21], [22]. At high frequencies the maximum spread is larger compared to what has been found in [18], but smaller than the one presented in [19], [21], [22]. For some of the phones quite significant dependence of TRP on the side of the head where the phone is positioned has been observed.…”

“…A maximum difference in TRP of some 12 dB between BHHR and BHHL has been found. In comparison, up to some 14 dB has been seen in [19] and up to some 11 dB in [22]. The comparison between the performance in FS setup and that in BHHR/BHHL setup has shown that the ability to transmit power is far better if the phone is in a hands-free installation.…”

“…The aim of this paper is to provide data for the ability of 16 mobile phones (the list of models, used in the study, common in the Nordic countries over the last years was provided by the Danish Energy Agency) to transmit and receive power. It should be mentioned that the work presented in this paper is a follow-up on similar tests conducted for phones common in the market at the time of publishing the results, see [17]- [22].…”

Effect of SAM hand phantom on TRP of EN‐DC 5G terminal

“…In addition, when we are using the mobile phone, the transmitting power and receiving sensitivity of the mobile phone will be reduced because the head and hand are close to the antenna of the mobile phone. Therefore, OTA needs to be tested not only in free space, but also in human head and hand environment 17‐19 . Nowadays, with the size of mobile terminal antenna becoming more and more compact, mobile phone manufacturers often use PIFA antenna or monopole antenna 20‐28 .…”