Measurements And Modeling On The Relationship Between Antenna Height And Wireless Large Scale Character Channel

In the last few years, the growing demand of wireless data services has brought great pressure on wireless network in dense urban environment. Small cells are widely deployed to increase data capacity. But when the outdoor base station and indoor users in high-rising buildings get close, indoor users begin to suffer dramatic change in path loss due to height difference between the transmitter (TX) and receiver (RX). In this paper, a measurement campaign to research the Outdoor-to-Indoor (021) path loss in metropolitan small cell scenario was carried out. A3D path loss is given based on the analysis of the measurement data.There are mainly two parts in our research:1. A measurement campaign is carried out in two scenarios:BUPT campus and China Mobile Innovation Plaza. In the measurements, both the TX and RX are deployed at different heights and distances to thoroughly study the factors influencing021path loss. Isotropic antennas were used to make sure the antenna gains of all directions are the same. The frequency of the signal is3.5GHz, which is proposed as the candidate band for4G mobile system. The building where the RX is deployed is higher than its surroundings, and the layout of each floor are identical, excluding the effect of the building structure and materials. The analysis of the measurement data shows that in typical small cell scenario, the021path loss has a tendency of increasing with the height difference, which is defined as height gain. Height gain is observed in both the outdoor part and the wall penetration part of the021path loss.2. A3D path loss model introducing height gain as a modification is given based on the measurement data. The analysis of the data shows that021path loss increases as the height difference increases, while the larger the height difference, the slower the slope. Another tendency observed that apart from the tendency of decreasing with the height difference, the increasing slope of path loss also decreases with the increasing of distance. The further the distance, the slower the path loss grows with height difference, despite of the overall increase of the path loss. This indicates that021path loss is related to both the height difference and distance between antennas. The3D path loss model is obtained through the following procedure: By taking the height difference into consideration when calculating the distance, the3D path loss of the basic part is given. And by introducing a height gain factor, the height gain of the wall penetration part is modeled based on measurement data. The path loss prediction with height gain model fits in well with the measurement data.