The high-altitude platform station (HAPS) is expected to function as a new mobile communication platform, that can provide mobile communication services such as long term evolution (LTE) or 5th generation new radio (5G NR) from the stratosphere to terrestrial user equipment (UE) directly. This is achieved by means of aerial vehicles fitted with radio equipment and located at an altitude of 20 km. HAPS can provide ultra-wide coverage as wide as 50 km to 100 km in radius and can realize disaster-resilient networks. The service area of HAPS overlaps that of the existing terrestrial mobile network owing to its ultra-wide coverage. Therefore, the operation of a coexistent HAPS/terrestrial network should be considered. From the viewpoint of spectral efficiency, co-channel spectrum sharing is desirable because it allows the reuse of the shared spectrum and dynamically distributes the frequency resource depending on mobile-traffic load. However, a large number of uplink signals from the terrestrial network can be superposed and interfere with the HAPS signal in such spectrum sharing. In particular, the interference power of the superposed signals becomes extremely large in the case of urban areas, where a massive number of users can transmit uplink signals. This paper proposes a system for uplink co-channel spectrum sharing between the HAPS and terrestrial networks. We evaluated the actual received power from the terrestrial network by an aerial radio-propagation measurement in real outdoor environments and the emission characteristics of an actual UE by a lab test. The evaluation results show the uplink interference from the terrestrial network and clarify the feasibility of our proposed system.
An Experimental Study of Uplink Co-Channel Spectrum-Sharing System between HAPS and Terrestrial Mobile Communication Networks
2020-11-01
1590519 byte
Conference paper
Electronic Resource
English