MIMO performance evaluation of automotive qualified LTE antennas

Future vehicles are expected to integrate multiple radio access technologies in order to support more efficiently traffic and infotainment applications. The focus of this paper is the performance evaluation of 3GPP Long Term Evolution (LTE) for automotive applications. The results presented are based on field measurements, which were carried out on a test track in Munich, Germany. The focus is the spectrum in 800 MHz, which is more challenging for multiple-input multiple-output (MIMO) antenna designs due to the difficulties of antenna decoupling. For the investigation an automotive qualified LTE MIMO antenna system is used. The presented results demonstrate that a performance deterioration of the antenna system occurs in areas close to the base station. It is shown that the deterioration is caused by shadowing between the two printed circuit board antennas comprising the antenna system. Moreover, it is illustrated that the signal-to-noise-plus-interference ratio (SINR), as opposed to the received signal strength indicator (RSSI), is a better suited parameter to determine the performance of the LTE link.