Path loss models in LOS conditions for relay mobile channels

Relaying technique is a key feature for the 3GPP LTE-Advanced system. In order to evaluate the system performance, path loss models for the links Base Station-Relay Station (BS-RS), Base Station-Mobile Station (BS-MS) and Relay Station-Mobile Station (RS-MS) must be investigated. This paper focuses on the RS-MS link. It studies the impact of the relay position and relay antenna height based on a measurement campaign focusing on Line of Sight (LOS) conditions. Furthermore, it aims to propose a log-distance Path Loss (PL) model. The analysis shows that the LOS PL model does not depend on the relay antenna height, while it depends on the RS position. The proposed PL model is the free space PL with a correction factor that varies between +/-5 dB depending on the RS position. In addition, the shadowing is characterized and its standard deviation varies between 4.5 dB and 5.7 dB.