Survey of Millimeter-Wave Propagation Measurements and Models in Indoor Environments

The millimeter-wave (mmWave) is expected to deliver a huge bandwidth to address the future demands for higher data rate transmissions. However, one of the major challenges in the mmWave band is the increase in signal loss as the operating frequency increases. This has attracted several research interests both from academia and the industry for indoor and outdoor mmWave operations. This paper focuses on the works that have been carried out in the study of the mmWave channel measurement in indoor environments. A survey of the measurement techniques, prominent path loss models, analysis of path loss and delay spread for mmWave in different indoor environments is presented. This covers the mmWave frequencies from 28 GHz to 100 GHz that have been considered in the last two decades. In addition, the possible future trends for the mmWave indoor propagation studies and measurements have been discussed. These include the critical indoor environment, the roles of artificial intelligence, channel characterization for indoor devices, reconfigurable intelligent surfaces, and mmWave for 6G systems. This survey can help engineers and researchers to plan, design, and optimize reliable 5G wireless indoor networks. It will also motivate the researchers and engineering communities towards finding a better outcome in the future trends of the mmWave indoor wireless network for 6G systems and beyond.

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Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Millimeter Wave Bands for 5G Cellular Communications

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v8i4.pp2254-2260 ◽

2018 ◽

Vol 8 (4) ◽

pp. 2254 ◽

Cited By ~ 1

Author(s):

Mohammed B. Majed ◽

Tharek A. Rahman ◽

Omar Abdul Aziz

Keyword(s):

Communication Networks ◽

Millimeter Wave ◽

Wide Spectrum ◽

Path Loss ◽

Separation Distance ◽

Propagation Path ◽

Delay Spread ◽

Propagation Time ◽

60 Ghz ◽

Rms Delay Spread

The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.

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Analysis of Propagation Characteristics for Various Subway Tunnel Scenarios at 28 GHz

International Journal of Antennas and Propagation ◽

10.1155/2021/7666624 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Chengjian Wang ◽

Wenli Ji ◽

Guoxin Zheng ◽

Asad Saleem

Keyword(s):

Ray Tracing ◽

Root Mean Square ◽

Millimeter Wave ◽

Measurement Data ◽

Path Loss ◽

Small Scale ◽

Delay Spread ◽

Mean Square ◽

Propagation Characteristics ◽

Subway Tunnels

In order to meet the higher data transmission rate requirements of subway communication services, the millimeter wave (mmWave) broadband communication is considered as a potential solution in 5G technology. Based on the channel measurement data in subway tunnels, this paper uses ray-tracing (RT) simulation to predict the propagation characteristics of the 28 GHz millimeter wave frequency band in different tunnel scenarios. A large number of simulations based on ray-tracing software have been carried out for tunnel models with different bending radiuses and different slopes, and we further compared the simulation results with the real time measurement data of various subway tunnels. The large-scale and small-scale propagation characteristics of the channel, such as path loss (PL), root mean square delay spread (RMS-DS), and angle spread (AS), for different tunnel scenarios are analyzed, and it was found that the tunnel with a greater slope causes larger path loss and root mean square delay spread. Furthermore, in the curved tunnel, the angle spread of the azimuth angle is larger than that in a straight tunnel. The proposed results can provide a reference for the design of future 5G communication systems in subway tunnels.

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Utilization of an OLED-Based VLC System in Office, Corridor, and Semi-Open Corridor Environments

Sensors ◽

10.3390/s20236869 ◽

2020 ◽

Vol 20 (23) ◽

pp. 6869

Author(s):

Zahra Nazari Chaleshtori ◽

Zabih Ghassemlooy ◽

Hossien B. Eldeeb ◽

Murat Uysal ◽

Stanislav Zvanovec

Keyword(s):

Indoor Localization ◽

Low Cost ◽

Flexible Substrate ◽

Path Loss ◽

Visual Display ◽

Outer Wall ◽

Channel Gain ◽

Delay Spread ◽

Indoor Environments ◽

Visible Light Communications

Organic light emitting diodes (OLEDs) have recently received growing interest for their merits as soft light and large panels at a low cost for the use in public places such as airports, shopping centers, offices, and train or bus stations. Moreover, the flexible substrate-based OLEDs provide an attractive feature of having curved or rolled lighting sources for the use in wearable devices and display panels. This technology can be implemented in visible light communications (VLC) for several applications such as visual display, data communications, and indoor localization. This article aims to investigate the use of flexible OLED-based VLC in indoor environments (i.e., office, corridor and semi-open corridor in shopping malls). We derive a two-term power series model to be match with the root-mean-square delay spread and optical path loss (OPL). We show that, for OLED positioned on outer-wall of shops, the channel gain is enhanced in contrast to them being positioned on the inner-wall. Moreover, the channel gain in empty environments is higher compare with the furnished rooms. We show that, the OPL for a 10 m link span are lower by 4.4 and 6.1 dB for the empty and semi-open corridors compared with the furnished rooms, when OLED is positioned on outer-wall of shops. Moreover, the channel gain in the corridor is higher compared with the semi-open corridor. We also show that, in furnished and semi-open corridors the OPL values are 55.6 and 57.2 dB at the center of corridor increasing to 87.6 and 90.7 dB at 20 m, respectively, when OLED is positioned on outer-wall of shops.

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Performance analysis of millimeter wave 5G networks for outdoor environment: propagation perspectives

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v20.i1.pp214-221 ◽

2020 ◽

Vol 20 (1) ◽

pp. 214

Author(s):

Naser Al-Falahy ◽

Mohammed AlMahamdy ◽

Ali M. Mahmood

Keyword(s):

Millimeter Wave ◽

Path Loss ◽

Outdoor Environment ◽

Delay Spread ◽

Data Traffic ◽

Mobile Access ◽

Massive Growth ◽

Fifth Generation ◽

Received Power ◽

Ray Tracing Simulation

<span>To cope with the massive growth in global mobile data traffic for 2020 and beyond, the Fifth Generation (5G) system is required to be developed as the current 4G system is expected to fall short behind the provision of such growth. 5G systems is anticipated to use millimeter wave (mm-wave) frequency bands (20 to 90) GHz, due to the availability of wide chunk of unexploited bandwidth. This is revolutionary step to use these bands because of their very different propagation conditions, atmospheric absorption and hardware constraints. However, such challenges could be compensated by means of beamforming/beamsteering and larger antenna array. In this paper, a comparative study aided with ray-tracing simulation has been performed to assess the feasibility of mm-wave in 5G system. Propagation characteristics of the 28GHz and 73 GHz bands have been studied and compared in a street canyon outdoor environment to simulate 5G outdoor mobile access. Simulation results were shown along with their comparison for both of the aforementioned frequencies. The results of propagation comparison have been reported in terms of path loss, k-factor, delay spread and received power for both 28 and 73 GHz bands.</span>

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Enhancing the Capacity of the Indoor 60 GHz Band Via Modified Indoor Environments Using Ring Frequency Selective Surface Wallpapers and Path Loss Models

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v8i5.pp3003-3020 ◽

2018 ◽

Vol 8 (5) ◽

pp. 3003

Author(s):

Nidal Qasem

Keyword(s):

Communication Systems ◽

Mimo Systems ◽

Path Loss ◽

Propagation Path ◽

Delay Spread ◽

Indoor Environments ◽

60 Ghz ◽

Loss Models ◽

Frequency Selective ◽

Ring Frequency

<span>The 60 GHz band has been selected for short-range communication systems to meet consumers’ needs for high data rates. However, this frequency is attenuated by obstacles. This study addresses the limitations of the 60 GHz band by modifying indoor environments with ring Frequency Selective Surfaces (FSSs) wallpaper, thereby increasing its utilization. The ring FSS wallpaper response at a 61.5 GHz frequency has been analyzed using both MATLAB and Computer Simulation Technology (CST) Microwave Studio (MWS) software. ‘Wireless InSite’ is also used to demonstrate enhanced wave propagation in a building modified with ring FSSs wallpaper. The demonstration is applied to Single Input Single Output (SISO) and Multiple Input Multiple Output (MIMO) systems to verify the effectiveness of FSSs on such systems’ capacity. The effectiveness of the suggested modification over delay spread has been studied for the MIMO scenario, as well as the effect of the human body on capacity. Simulation results presented here show that modifying a building using ring FSS wallpaper is an attractive scheme for significantly improving the indoor 60 GHz wireless communications band. This paper also presents and compares two large-scale indoor propagation Path Loss Models (PLMs), the Close-In (CI) free space reference distance model and the Floating Intercept (FI) model. Data obtained from ‘Wireless InSite’ over distances ranging from 4 to 14.31 m is analyzed. Results show that the CI model provides good estimation and exhibits stable behavior over frequencies and distances, with a solid physical basis and less computational complexity when compared to the FI model. </span>

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Indoor Corridor Wideband Radio Propagation Measurements and Channel Models for 5G Millimeter Wave Wireless Communications at 19 GHz, 28 GHz, and 38 GHz Bands

Wireless Communications and Mobile Computing ◽

10.1155/2018/6369517 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 16

Author(s):

Ahmed M. Al-samman ◽

Tharek Abd Rahman ◽

Marwan Hadri Azmi

Keyword(s):

Millimeter Wave ◽

Free Space ◽

Path Loss ◽

Delay Spread ◽

Angle Of Arrival ◽

Microwave Band ◽

Power Delay Profile ◽

Rms Delay Spread ◽

Path Loss Exponent ◽

Line Slope

This paper presents millimeter wave (mmWave) measurements in an indoor environment. The high demands for the future applications in the 5G system require more capacity. In the microwave band below 6 GHz, most of the available bands are occupied; hence, the microwave band above 6 GHz and mmWave band can be used for the 5G system to cover the bandwidth required for all 5G applications. In this paper, the propagation characteristics at three different bands above 6 GHz (19, 28, and 38 GHz) are investigated in an indoor corridor environment for line of sight (LOS) and non-LOS (NLOS) scenarios. Five different path loss models are studied for this environment, namely, close-in (CI) free space path loss, floating-intercept (FI), frequency attenuation (FA) path loss, alpha-beta-gamma (ABG), and close-in free space reference distance with frequency weighting (CIF) models. Important statistical properties, such as power delay profile (PDP), root mean square (RMS) delay spread, and azimuth angle spread, are obtained and compared for different bands. The results for the path loss model found that the path loss exponent (PLE) and line slope values for all models are less than the free space path loss exponent of 2. The RMS delay spread for all bands is low for the LOS scenario, and only the directed path is contributed in some spatial locations. For the NLOS scenario, the angle of arrival (AOA) is extensively investigated, and the results indicated that the channel propagation for 5G using high directional antenna should be used in the beamforming technique to receive the signal and collect all multipath components from different angles in a particular mobile location.

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Path Loss Models and Delay Spread parameters for the Millimetre Wave Channel in Indoor Environments

2020 14th European Conference on Antennas and Propagation (EuCAP) ◽

10.23919/eucap48036.2020.9135601 ◽

2020 ◽

Author(s):

Sana Salous ◽

Saied El-Faitori

Keyword(s):

Path Loss ◽

Delay Spread ◽

Indoor Environments ◽

Millimetre Wave ◽

Wave Channel ◽

Loss Models ◽

Spread Parameters

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Millimeter Wave Propagation Measurements and Characteristics for 5G System

Applied Sciences ◽

10.3390/app10010335 ◽

2020 ◽

Vol 10 (1) ◽

pp. 335 ◽

Cited By ~ 1

Author(s):

Ahmed M. Al-Samman ◽

Marwan Hadri Azmi ◽

Y. A. Al-Gumaei ◽

Tawfik Al-Hadhrami ◽

Tharek Abd. Rahman ◽

...

Keyword(s):

Millimeter Wave ◽

Measurement Data ◽

Path Loss ◽

Ultra Wideband ◽

Line Of Sight ◽

Delay Spread ◽

Rms Delay Spread ◽

5G Systems ◽

Mean Excess Delay ◽

Wideband Channel

In future 5G systems, the millimeter wave (mmWave) band will be used to support a large capacity for current mobile broadband. Therefore, the radio access technology (RAT) should be made available for 5G devices to help in distinct situations, for example device-to-device communications (D2D) and multi-hops. This paper presents ultra-wideband channel measurements for millimeter wave bands at 19, 28, and 38 GHz. We used an ultra-wideband channel sounder (1 GHz bandwidth) in an indoor to outdoor (I2O) environment for non-line-of-sight (NLOS) scenarios. In an NLOS environment, there is no direct path (line of sight), and all of the contributed paths are received from different physical objects by refection propagation phenomena. Hence, in this work, a directional horn antenna (high gain) was used at the transmitter, while an omnidirectional antenna was used at the receiver to collect the radio signals from all directions. The path loss and temporal dispersion were examined based on the acquired measurement data—the 5G propagation characteristics. Two different path loss models were used, namely close-in (CI) free space reference distance and alpha-beta-gamma (ABG) models. The time dispersion parameters were provided based on a mean excess delay, a root mean square (RMS) delay spread, and a maximum excess delay. The path loss exponent for this NLOS specific environment was found to be low for all of the proposed frequencies, and the RMS delay spread values were less than 30 ns for all of the measured frequencies, and the average RMS delay spread values were 19.2, 19.3, and 20.3 ns for 19, 28, and 38 GHz frequencies, respectively. Moreover, the mean excess delay values were found also at 26.1, 25.8, and 27.3 ns for 19, 28, and 38 GHz frequencies, respectively. The propagation signal through the NLOS channel at 19, 28, and 38 GHz was strong with a low delay; it is concluded that these bands are reliable for 5G systems in short-range applications.

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Measurement-Based 5G Millimeter-Wave Propagation Characterization in Vegetated Suburban Macrocell Environments

10.36227/techrxiv.11864277.v1 ◽

2020 ◽

Author(s):

Peize Zhang ◽

Bensheng Yang ◽

Cheng Yi ◽

Haiming Wang ◽

Xiaohu You

Keyword(s):

Millimeter Wave ◽

Measurement Data ◽

Path Loss ◽

Angular Spread ◽

Line Of Sight ◽

Small Scale ◽

Delay Spread ◽

Shadow Fading ◽

Loss Prediction ◽

The Time Domain

An empirically based analysis of propagation characteristics in two vegetated suburban areas with different types and fractions of vegetation cover in 5G millimeter-wave bands is presented. A basic distance-dependent path loss model with a Gaussian random variance for shadow fading is utilized in accordance with the maximum-power directional and omnidirectional measurement data, therein exploiting significant path loss exponents in the presence of vegetation. In comparison with the existing ITU-R and 3GPP models, the effect of dense-leaved trees on path loss prediction is similar to that of buildings, whereas these standard models are inapplicable for sparse obstacle-line-of-sight (OLoS) links. Consequently, an azimuth-angle-based path loss characterization is proposed considering the antenna pattern, beam misalignment, and blockage effects. Moreover, several composite and cluster-level small-scale channel parameters, such as the number of clusters, delay spread, and angular spread, are extracted. Analysis of the first-arrival cluster in the OLoS setting reveals that forward scattering through foliage is still dominant and is expected to produce a larger azimuth angular spread of the arrival and compact multipath components in the time domain compared with line-of-sight and reflected clusters. Measurement results improve existing 3GPP channel models for suburban macrocell scenarios in millimeter-wave bands.

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