Enhancing Vehicular Link Performance Using Directional Antennas at the Terminal

Abstract

Cellular networks will be one of the main pillars in the development of future vehicular communications. However, downlink (DL) and uplink (UL) channels must be improved to cope with the required reliability and high throughput of the coming vehicular use cases. Vehicle side solutions which benefit from the high antenna gains could improve the performance of the UL channel whose coverage is limited by UL transmit power. In this paper we experimentally evaluate the performance of a directional antennas switching system based on live Long Term Evolution (LTE) measurements. A total of more than 150 km have been driven comprising different radio propagation scenarios. The results show considerable improvements of Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ), together with a reduction of handovers specially in scenarios with high Line-Of-Sight probability. Additionally, it has been found that the UL throughput does not improve with the increase of antenna gain probably due to the UL Power Control mechanism used in LTE.