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This paper presents multiple-input multiple-output (MIMO) measurements in the 20-GHz band, and evaluates the basic performance of massive MIMO systems when considering 100 elements at a base station (BS) and seven user equipment units. First, it is shown that zero forcing (ZF) is essential as a transmission scheme in massive MIMO systems, whereas the maximum-ratio combining method cannot reduce interference...
In the 5G system, high frequency bands over 6 GHz (6–100 GHz) will be a key factor in providing a very wide bandwidth. Because of high path losses, these bands are considered to use for small cells. To design radio links with high accuracy and evaluate 5G system performances for various scenarios, channel characteristics must be clarified. In this paper, we clarify channel characteristics in an outdoor...
This paper clarifies the effects of configuration of a MIMO base station antenna on the channel capacity in line-of-sight street cell environment. It is shown that the optimum beam width in the horizontal plane depends on the road width and the distance from the base station. Moreover, it is also shown that the channel capacity decrease as the service area becomes wider.
In the 5G system, high frequency bands over 6 GHz (6–100 GHz) will be a key factor in providing a very wide bandwidth. To compensate for high propagation loss of the high frequency bands and improve user throughput, massive-array antennas and beamforming techniques are considered for use. Under real environment, the beamforming gains of massive-array antennas are degraded by propagation channel characteristics...
This paper presents path loss frequency dependence in an urban macro (UMa) cell environment on the basis of measurement campaign results using three frequencies between 2 and 26 GHz. For a 3rd Generation Partnership Project UMa model above 6 GHz band, the dependence is shown by 20log(f). The measurement results show that the dependence is similar in Line-of-Sight areas but that in Non-Line-of-Sight...
In high frequency bands over 6 GHz (6–100 GHz), the scattering properties of radio waves due to the roughness of building walls are considered to be different from those for the ultra high frequency (UHF) bands. In this paper, we present wall scattering characteristics based on an effective roughness (ER) model with point cloud data. Based on a comparison of simulation and measurement results, it...
This paper presents time-variant channel characteristics at the 20-GHz band for line of sight (LoS) scenarios in an urban street canyon environment. A measurement campaign is conducted using a channel sounder for the 20-GHz band with a 50-MHz-bandwidth orthogonal frequency-division multiplexing signal. A uniform planar array (UPA) in a 16-by-16 matrix is used on the receiver side to measure time-variant...
Measurement results of path loss characteristics up to 37 GHz band in street microcell environments are described. Ray tracing is used to analyze the effects of building shapes on path loss characteristics at an intersection. A comparison between measured and calculated results clarified the dominant paths in which specular reflection from a chamfered shaped building contributes the power. The results...
The measurement results of outdoor-to-indoor path loss characteristics in multiple frequency bands from microwave to millimeter wave are described. We clarified that the path loss characteristics dependence on frequency. Moreover, ray tracing is used to analyze the propagation phenomena causing frequency dependence. A comparison between measured and calculated results clarified the dominant paths...
The fifth-generation (5G) mobile communication systems will benefit immensely with the extension of their operation to mmWave bands. To this end, understanding the system-level performance of mmWave cellular networks carries critical importance. In this paper, we investigate the average signal-to-interference plus noise ratio (SINR) distribution (geometry) performance for indoor and outdoor mobile...
This paper overviews the latest developments in mobile radio propagation research and presents our views looking to the future. Radio propagation research has high affinity to machine learning such as deep learning since it can deal with copious amounts of measurement data. Deep learning is useful for image recognition and can be applied to modeling of building materials. This modeling achieved through...
We evaluate the user rate performance of massive MIMO small cells in hot-spot areas. In particular, with the use of the 28GHz millimeter wave band ray-tracing channel data generated according to the realistic map in Shinjuku, Tokyo, Japan, we investigate the user-specific rates in an area of 150m×120m. The results show promising rate performances with the use of a variety of beamforming schemes in...
This paper describes analytical results obtained for floor penetration loss characteristics and their frequency dependency by measuring in multiple frequency bands, including those above 6 GHz, in an indoor office environment. Measurement and analysis results show that the floor penetration loss depends on two dominant components: paths through floors and outside buildings. It was clarified that the...
For fifth generation mobile communication systems (5G) utilization of band from 6 to 100 GHz are investigated to increase the system capacity, because ensuring a wide frequency band above 6 GHz is relatively easier than that under 6 GHz, which is used for IMT-Advanced systems. Moreover, utilizing small cell with base station antenna of which height is low is one of the promising candidates, since...
Recently, mobile networks employing high-speed high-capacity communications have been investigated extensively to satisfy the demand for the faster and larger data communication. As one of the approaches, frequencies between 6 and 100 GHz bands are the candidates to utilize the relatively wide frequency bandwidths. Accordingly, the characteristics of radio propagation loss in these frequency bands...
Recently, mobile communication system for the 5th generation (5G) has been extensively investigated to satisfy the need for high-speed and high-capacity communication. In order to realize the higher and larger data communication, one of the approaches is to utilize high frequencies such as high SHF (above 6 GHz) and EHF (30–100 GHz) [1]. These frequency bands are expected to be applied for outdoor...
Mobile networks employing higher data rate and speed have been investigated for deployment of 5G mobile communication systems in urban microcellular environment. One of the approaches to achieve this goal, frequencies between 6 and 100 GHz are candidate to be utilized due to rich frequency spectrum. However radio propagation loss in these high frequencies is not characterized yet. Ray tracing (RT)...
Recently, the next generation (5G) mobile communication system has been actively investigated all over the world, in order to satisfy the strong demand for the faster and larger data communication. not only UHF band but also SHF/EHF bands have been much attracted much attention. Therefore, frequency characteristic of radio propagation loss must be studied. We previously investigated the outdoor to...
Recently, mobile networks employing high-speed high-capacity communications have been investigated extensively to satisfy the strong demand for the faster and larger data communication beyond 2020 as the 5th generation (5G) mobile communication system. As one of the approaches, high-SHF (6 – 30 GHz) and EHF (mainly 30 – 60 GHz) bands are the candidates to utilize the relatively wide frequency band...
Fifth generation (5G) mobile communication systems are being actively investigated to increase the system capacity. For 5G, utilizing frequency bands above 6 GHz is being investigated because it is considered that ensuring a wide frequency band above 6 GHz is relatively easier than that under 6 GHz, which is used for IMT-Advanced systems. In this report, a site general type path loss prediction model...
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