Influence of reflected waves on communication between floors of LOS buildings

In order to overcome the increasing traffic problems of mobile terminals used in high-rise floors of buildings, the three-dimensional cell configuration which places small cells on various floors is considered. In order to evaluate wireless transmission technologies for the three-dimensional cell configuration, it is necessary to clarify the time-spatial characteristics of the path loss, delay profile and spatial arrival angular profile for waves travelling from one indoor space in a high-rise office to another such indoor space. In order to evaluate these time-spatial characteristics for each arrival path, our previous study introduced a ray trace system applicable to indoor-outdoor layouts. Then, to evaluate the predicted accuracy of the system, we calculated the path loss characteristic, which is the most fundamental characteristic of the time-spatial characteristics, for a simple indoor-outdoor layout of two cuboids facing each other. We confirmed that the system could reproduce the measured results except when the receiving antenna was far from the window. This paper proves that this difference in measured and calculated results was due to the omission of the waves reflected between buildings. We add the wall reflections to a simple indoor-outdoor layout and show that the calculated results well reproduce the measured results.