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1
Al-Saman, Ahmed, Michael Cheffena, Olakunle Elijah, Yousef A. Al-Gumaei, Sharul Kamal Abdul Rahim e Tawfik Al-Hadhrami. "Survey of Millimeter-Wave Propagation Measurements and Models in Indoor Environments". Electronics 10, n. 14 (11 luglio 2021): 1653. http://dx.doi.org/10.3390/electronics10141653.
Testo completoAbstract (sommario):
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.
2
Liu, Baobao, Pan Tang, Jianhua Zhang, Yue Yin, Guangyi Liu e Liang Xia. "Propagation Characteristics Comparisons between mmWave and Visible Light Bands in the Conference Scenario". Photonics 9, n. 4 (1 aprile 2022): 228. http://dx.doi.org/10.3390/photonics9040228.
Testo completoAbstract (sommario):
Millimeter-wave (mmWave) communications and visible light communications (VLC) are proposed to form hybrid mmWave/VLC systems. Furthermore, channel modeling is the foundation of system design and optimization. In this paper, we compare the propagation characteristics, including path loss, root mean square (RMS) delay spread (DS), K-factor, and cluster characteristics, between mmWave and VLC bands based on a measurement campaign and ray tracing simulation in a conference room. We find that the optical path loss (OPL) of VLC channels is highly dependent on the physical size of the photodetectors (PDs). Therefore, an OPL model is further proposed as a function of the distance and size of PDs. We also find that VLC channels suffer faster decay than mmWave channels. Moreover, the smaller RMS DS in VLC bands shows a weaker delay dispersion than mmWave channels. The results of K-factor indicate that line-of-sight (LOS) components mainly account for more power for mmWave in LOS scenarios. However, non-LOS (NLOS) components can be stronger for VLC at a large distance. Furthermore, the K-Power-Means algorithm is used to perform clustering. The fitting cluster number is 5 and 6 for mmWave and VLC channels, respectively. The clustering results reveal the temporal sparsity in mmWave bands and show that VLC channels have a large angular spread.
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Rodríguez-Corbo, Fidel, Leyre Azpilicueta, Mikel Celaya-Echarri, Peio López-Iturri, Imanol Picallo, Francisco Falcone e Ana Alejos. "Millimeter Wave Spatial Channel Characterization for Vehicular Communications". Proceedings 42, n. 1 (14 novembre 2019): 64. http://dx.doi.org/10.3390/ecsa-6-06562.
Testo completoAbstract (sommario):
With the growing demand of vehicle-mounted sensors over the last years, the amount of critical data communications has increased significantly. Developing applications such as autonomous vehicles, drones or real-time high-definition entertainment requires high data-rates in the order of multiple Gbps. In the next generation of vehicle-to-everything (V2X) networks, a wider bandwidth will be needed, as well as more precise localization capabilities and lower transmission latencies than current vehicular communication systems due to safety application requirements; 5G millimeter wave (mmWave) technology is envisioned to be the key factor in the development of this next generation of vehicular communications. However, the implementation of mmWave links arises with difficulties due to blocking effects between mmWave transceivers, as well as different channel impairments for these high frequency bands. In this work, the mmWave channel propagation characterization for V2X communications has been performed by means of a deterministic in-house 3D ray launching simulation technique. A complex heterogeneous urban scenario has been modeled to analyze the different propagation phenomena of multiple mmWave V2X links. Results for large and small-scale propagation effects are obtained for line-of-sight (LOS) and non-LOS (NLOS) trajectories, enabling inter-data vehicular comparison. These analyzed results and the proposed methodology can aid in an adequate design and implementation of next generation vehicular networks.
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Rodríguez-Corbo, Fidel Alejandro, Leyre Azpilicueta, Mikel Celaya-Echarri, Peio Lopez-Iturri, Ana V. Alejos e Francisco Falcone. "Deterministic Propagation Approach for Millimeter-Wave Outdoor Smart Parking Solution Deployment". Engineering Proceedings 2, n. 1 (14 novembre 2020): 81. http://dx.doi.org/10.3390/ecsa-7-08231.
Testo completoAbstract (sommario):
Impact factor as an indicator of efficiency or sustainability is entirely correlated with the continuous development of the smart city concept technology application. Intelligent transportation systems (ITSs) and particularly autonomous vehicles are expected to play an important role in this challenging environment. Fast and secure connections will be pivotal in order to achieve this new vehicular communications’ application era. The use of millimeter-wave (mmWave) frequency range is the most promising approach to allow these real-time, high-demand applications that require higher bandwidth with the minimum possible latency. However, an in-depth mmWave-channel characterization of the environment is required for a proper mmWave-based solution deployment. In this work, a complete radio wave propagation channel characterization for a mmWave smart parking solution deployment in a complex outdoor environment was assessed at a 28 GHz frequency band. The considered scenario is a parking lot placed in an open free university campus area surrounded by inhomogeneous vegetation. The vehicle and vegetation density within the scenario, in terms of inherent transceivers density and communication impairments, leads to overall system operation challenges, given by multiple communication links operation at line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. By means of an in-house developed 3D ray launching (3D-RL) algorithm, the impact of variable vegetation density is addressed, providing precise modelling estimations of large-scale multipath propagation effects in terms of received power levels and path loss. The obtained results along with the proposed simulation methodology can aid in an adequate characterization of an mmWave communication channel for new vehicular communications networks, applications, and deployments, considering the outdoor conditions as well as the impact of different vegetation densities, for current as well as for future wireless technologies.
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Gulfam, Sardar, Syed Nawaz, Konstantinos Baltzis, Abrar Ahmed e Noor Khan. "Characterization of Fading Statistics of mmWave (28 GHz and 38 GHz) Outdoor and Indoor Radio Propagation Channels". Technologies 7, n. 1 (9 gennaio 2019): 9. http://dx.doi.org/10.3390/technologies7010009.
Testo completoAbstract (sommario):
Extension of usable frequency spectrum from microwave to millimeter-wave (mmWave) is one of the key research directions in addressing the capacity demands of emerging 5th-generation communication networks. This paper presents a thorough analysis on the azimuthal multipath shape factors and second-order fading statistics (SOFS) of outdoor and indoor mmWave radio propagation channels. The well-established analytical relationship of plain angular statistics of a radio propagation channel with the channel’s fading statistics is used to study the channel’s fading characteristics. The plain angle-of-arrival measurement results available in the open literature for four different outdoor radio propagation scenarios at 38 GHz, as well as nine different indoor radio propagation scenarios at 28 GHz and 38 GHz bands, are extracted by using different graphical data interpretation techniques. The considered quantifiers for energy dispersion in angular domain and SOFS are true standard-deviation, angular spread, angular constriction, and direction of maximum fading; and spatial coherence distance, spatial auto-covariance, average fade duration, and level-crossing-rate; respectively. This study focuses on the angular spread analysis only in the azimuth plane. The conducted analysis on angular spread and SOFS is of high significance in designing modulation schemes, equalization schemes, antenna-beams, channel estimation, error-correction techniques, and interleaving algorithms; for mmWave outdoor and indoor radio propagation environments.
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Rahayu, Ismalia, e Ahmad Firdausi. "5G Channel Model for Frequencies 28 GHz, 73 GHz and 4 GHz with Influence of Temperature in Bandung". Jurnal Teknologi Elektro 13, n. 2 (31 maggio 2022): 94. http://dx.doi.org/10.22441/jte.2022.v13i2.006.
Testo completoAbstract (sommario):
The 5G channel model is the latest research on future cellular communication by considering the proposed millimeter wave (mmwave) as an enabling technology for the realization of connectivity in the 5G era. However, mmwave signal propagation suffers a high propagation loss to sensitivity to delay, resulting in a high probability and a low signal to signal ratio (SNR). This can take into account the potential for millimeter wave (mmwave) frequencies of 28, 73 and 4 GHz which are capable of meeting wide bandwidth requirements and data rates of up to Gbps for various scenarios such as Urban Microcell (UMi) and Urban Macrocell (UMa). The area used to conduct this research is in Indonesia because it is a tropical region that has high rainfall so that it can determine the effect that occurs when it is at maximum and minimum temperatures in each month. Therefore, to determine the characteristics of the 28, 73 and 4 GHz channels in the city of Bandung. This study discusses large-scale mmwave characteristics such as path loss, delay spread and power delay profile for line-of-sight (LOS) and non-line-of-sight (NLOS) cases and compares directional and omnidirectional propagation. In this study the Urban Microcell (UMi) scenario was carried out at a distance of 20 meters to 200 meters with a frequency of 28 GHz and 73 GHz, then for the Urban Macro cell (UMa) scenario at a frequency of 4 GHz with a distance of 50 meters to 500 meters.
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Dos Anjos, Andre Antonio, Tiago Reis Rufino Marins, Carlos Rafael Nogueira Da Silva, Vicent Miquel Rodrigo Penarrocha, Lorenzo Rubio, Juan Reig, Rausley Adriano Amaral De Souza e Michel Daoud Yacoub. "Higher Order Statistics in a mmWave Propagation Environment". IEEE Access 7 (2019): 103876–92. http://dx.doi.org/10.1109/access.2019.2930931.
Testo completo
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Yao, H., X. Wang, H. Qi e X. Liang. "TIGHTLY COUPLED INDOOR POSITIONING USING UWB/MMWAVE RADAR/IMU". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-3/W1-2022 (5 maggio 2022): 323–29. http://dx.doi.org/10.5194/isprs-archives-xlvi-3-w1-2022-323-2022.
Testo completoAbstract (sommario):
Abstract. The ultra-wideband (UWB)-based positioning has a wide internet of things applications such as smart medical and smart logistics, due to its high positioning accuracy. However, non-line-of-sight radio propagation degrades UWB positioning accuracy. The inertial measurement unit (IMU) can achieve positioning with high accuracy in a short time. In addition, the millimeter wave (mmWave) radar can work well in scenes such as fog, smoke, dust, and other small particles due to the longer wavelength of mmWave Radar, but the drift error of IMU and mmWave radar are all increased rapidly over time. This paper achieves the tight coupling of UWB and IMU, UWB and mmWave radar based on the extended Kalman filter, respectively. The field experiments were conducted based on a handheld platform in an indoor scene to evaluate and compare the performance of the fusion position systems; the experiment results demonstrated that the positioning accuracy by fusing UWB/IMU and UWB/mmWave was significantly higher than that of the positioning using a single sensor.
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Jiang, Ting, Maozhong Song, Xiaorong Zhu e Xu Liu. "Channel Estimation for Broadband Millimeter Wave MIMO Systems Based on High-Order PARALIND Model". Wireless Communications and Mobile Computing 2021 (23 novembre 2021): 1–12. http://dx.doi.org/10.1155/2021/6408442.
Testo completoAbstract (sommario):
Channel state information (CSI) is important to improve the performance of wireless transmission. However, the problems of high propagation path loss, multipath, and frequency selective fading make it difficult to obtain the CSI in broadband millimeter-wave (mmWave) system. Based on the inherent multidimensional structure of mmWave multipath channels and the correlation between channel dimensions, mmWave multiple input multiple output (MIMO) channels are modelled as high-order parallel profiles with linear dependence (PARALIND) model in this paper, and a new PARALIND-based channel estimation algorithm is proposed for broadband mmWave system. Due to the structural property of PARALIND model, the proposed algorithm firstly separates the multipath channels of different scatterers by PARALIND decomposition and then estimates the channel parameters from the factor matrices decomposed from the model based on their structures. Meanwhile, the performance of mmWave channel estimation is analysed theoretically. A necessary condition for channel parameter estimation is given based on the uniqueness principle of PARALIND model. Simulation results show that the proposed algorithm performs better than traditional compressive sensing-based channel estimation algorithms.
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Idan, Hayder R., Basim K. AL-Shammari e Hasan F. Khazal. "mmWave Compound Link Budget Model of Dust and Humidity Effect". Wasit Journal of Engineering Sciences 11, n. 1 (1 aprile 2023): 45–60. http://dx.doi.org/10.31185/ejuow.vol11.iss1.323.
Testo completoAbstract (sommario):
mmWave Path Loss (PL) Link Budget (LB) modeling considerations are based on many different factors. For instance, the third generation partnership project (3GPP) model is mainly based on the distance from an Access Point (AP) and the frequency of transmission as well as the transmission link budget situation. Furthermore, there are certain interesting models about the effects of dust and humidity on the mmWave propagation. These models had introduced the consequences of the humid and dusty environments without consideration for the additional mmWave transmission LB parameters. First of all, this paper introduces an average dust and humidity model based on statistical Z-test in order to overcome the variation in the results between the three chosen models for dust and humidity effect in the mmWave range. Secondly, it proposes LB compound model, that comprises 3GPP PL LB with an average dust and humidity model. This introduced compound model has been applied on RMa PL LB with and without the presence of dust and humidity. The simulation of the presented model has been applied for distinct distances from the AP and mmWave transmission frequency range from 0.5 to 30 GHz.
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Rodríguez-Corbo, Fidel Alejandro, Leyre Azpilicueta, Mikel Celaya-Echarri, Peio Lopez-Iturri, Imanol Picallo, Francisco Falcone e Ana Vazquez Alejos. "Deterministic 3D Ray-Launching Millimeter Wave Channel Characterization for Vehicular Communications in Urban Environments". Sensors 20, n. 18 (16 settembre 2020): 5284. http://dx.doi.org/10.3390/s20185284.
Testo completoAbstract (sommario):
The increasing demand for more sensors inside vehicles pursues the intention of making vehicles more “intelligent”. In this context, the vision of fully connected and autonomous cars is becoming more tangible and will turn into a reality in the coming years. The use of these intelligent transport systems will allow the integration of efficient performance in terms of route control, fuel consumption, and traffic administration, among others. Future vehicle-to-everything (V2X) communication will require a wider bandwidth as well as lower latencies than current technologies can offer, to support high-constraint safety applications and data exhaustive information exchanges. To this end, recent investigations have proposed the adoption of the millimeter wave (mmWave) bands to achieve high throughput and low latencies. However, mmWave communications come with high constraints for implementation due to higher free-space losses, poor diffraction, poor signal penetration, among other channel impairments for these high-frequency bands. In this work, a V2X communication channel in the mmWave (28 GHz) band is analyzed by a combination of an empirical study and a deterministic simulation with an in-house 3D ray-launching algorithm. Multiple mmWave V2X links has been modeled for a complex heterogeneous urban scenario in order to capture and analyze different propagation phenomena, providing full volumetric estimation of frequency/power as well as time domain parameters. Large- and small-scale propagation parameters are obtained for a combination of different situations, taking into account the obstruction between the transceivers of vehicles of distinct sizes. These results can aid in the development of modeling techniques for the implementation of mmWave frequency bands in the vehicular context, with the capability of adapting to different scenario requirements in terms of network topology, user density, or transceiver location. The proposed methodology provides accurate wireless channel estimation within the complete volume of the scenario under analysis, considering detailed topological characteristics.
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Azpilicueta, Leyre, Peio Lopez-Iturri, Jaime Zuñiga-Mejia, Mikel Celaya-Echarri, Fidel Alejandro Rodríguez-Corbo, Cesar Vargas-Rosales, Erik Aguirre, David G. Michelson e Francisco Falcone. "Fifth-Generation (5G) mmWave Spatial Channel Characterization for Urban Environments’ System Analysis". Sensors 20, n. 18 (18 settembre 2020): 5360. http://dx.doi.org/10.3390/s20185360.
Testo completoAbstract (sommario):
In this work, the channel characterization in terms of large-scale propagation, small-scale propagation, statistical and interference analysis of Fifth-Generation (5G) Millimeter Wave (mmWave) bands for wireless networks for 28, 30 and 60 GHz is presented in both an outdoor urban complex scenario and an indoor scenario, in order to consider a multi-functional, large node-density 5G network operation. An in-house deterministic Three-Dimensional Ray-Launching (3D-RL) code has been used for that purpose, considering all the material properties of the obstacles within the scenario at the frequency under analysis, with the aid of purpose-specific implemented mmWave simulation modules. Different beamforming radiation patterns of the transmitter antenna have been considered, emulating a 5G system operation. Spatial interference analysis as well as time domain characteristics have been retrieved as a function of node location and configuration.
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Antonescu, Bogdan, Miead Tehrani Moayyed e Stefano Basagni. "Clustering Algorithms and Validation Indices for a Wide mmWave Spectrum". Information 10, n. 9 (19 settembre 2019): 287. http://dx.doi.org/10.3390/info10090287.
Testo completoAbstract (sommario):
Radio channel propagation models for the millimeter wave (mmWave) spectrum are extremely important for planning future 5G wireless communication systems. Transmitted radio signals are received as clusters of multipath rays. Identifying these clusters provides better spatial and temporal characteristics of the mmWave channel. This paper deals with the clustering process and its validation across a wide range of frequencies in the mmWave spectrum below 100 GHz. By way of simulations, we show that in outdoor communication scenarios clustering of received rays is influenced by the frequency of the transmitted signal. This demonstrates the sparse characteristic of the mmWave spectrum (i.e., we obtain a lower number of rays at the receiver for the same urban scenario). We use the well-known k-means clustering algorithm to group arriving rays at the receiver. The accuracy of this partitioning is studied with both cluster validity indices (CVIs) and score fusion techniques. Finally, we analyze how the clustering solution changes with narrower-beam antennas, and we provide a comparison of the cluster characteristics for different types of antennas.
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Kei Sakaguchi, Takumi Yoneda, Masashi Iwabuchi e Tomoki Murakami. "mmWave massive analog relay MIMO". ITU Journal on Future and Evolving Technologies 2, n. 6 (24 settembre 2021): 43–55. http://dx.doi.org/10.52953/wzof2275.
Testo completoAbstract (sommario):
Millimeter-Wave (mmWave) communications are a key technology to realize ultra-high data rate and ultra-low latency wireless communications. Compared with conventional communication systems in the microwave band such as 4G/LTE, mmWave communications employ a higher frequency band which allows a wider bandwidth and is suitable for large capacity communications. It is expected to be applied to various use cases such as mmWave cellular networks and vehicular networks. However, due to the strong diffraction loss and the path loss in the mmWave band, it is difficult or even impossible to achieve high channel capacity for User Equipment (UE) located in Non-Line-Of-Sight (NLOS) environments. To solve the problem, the deployment of relay nodes has been considered. In this paper, we consider the use of massive analog Relay Stations (RSs) to relay the transmission signals. By relaying the signals by a large number of RSs, an artificial Multiple-Input Multiple-Output (MIMO) propagation environment can be formed, which enables mmWave MIMO communications to the NLOS environment. We describe a theoretical study of a massive relay MIMO system and extend it to include multi-hop relays. Simulations are conducted, and the numerical results show that the proposed system achieves high data rates even in a grid-like urban environment.
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Attiah, Mothana L., Azmi Awang Md Isa, Zahriladha Zakaria, Nor Fadzilah Abdullah, Mahamod Ismail e Rosdiadee Nordin. "Adaptive Multi-state Millimeter Wave Cell Selection Scheme for 5G communication". International Journal of Electrical and Computer Engineering (IJECE) 8, n. 5 (1 ottobre 2018): 2967. http://dx.doi.org/10.11591/ijece.v8i5.pp2967-2978.
Testo completoAbstract (sommario):
<p>Millimeter wave bands have been introduced as one of the most promising solutions to alleviate the spectrum secrecy in the upcoming future cellular technology (5G) due the enormous amount of raw bandwidth available in these bands. However, the inherent propagation characteristics of mmWave frequencies could impose new challenges i.e. higher path loss, atmospheric absorption, and rain attenuation which in turn increase the outage probability and hence, degrading the overall system performance. Therefore, in this paper, a novel flexible scheme is proposed namely Adaptive Multi-State MmWave Cell Selection (AMSMC-S) through adopting three classes of mmWave base stations, able to operate at various mmWave carrier frequencies (73, 38 and 28 GHz). Two mmWave cellular Grid-Based cell deployment scenarios have been implemented with two inter-site-distances 200 m and 300 m, corresponding to target area of (2.1 km2) and (2.2 km2). The maximum SINR value at the user equipment (UE) is taken in to consideration to enrich the mobile user experience. Numerical results show an improvement of overall system performance, where the outage probability reduced significantly to zero while maintaining an acceptable performance of the 5G systems with approximately more than 50% of the mobile stations with more than 1Gbps data rate. </p>
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Liang, Yiqun, Hui Li, Yuan Tian, Yi Li e Wenhua Wang. "SDR-Based 28 GHz mmWave Channel Modeling of Railway Marshaling Yard". Sensors 23, n. 19 (27 settembre 2023): 8108. http://dx.doi.org/10.3390/s23198108.
Testo completoAbstract (sommario):
Compared with railway communication service requirements on the mainline, requirements in hotspots such as stations and yards are more complicated in terms of service types as well as bandwidth, of which railway-dedicated mobile communication systems such as 5G-R facilitated with dedicated frequency support cannot meet the entire communication requirements. Therefore, other radio-communication technologies need to be adopted as a supplement, among which the mmWave communication system is a promising technology, especially for large bandwidth communication between train and trackside. However, there is a lack of evaluation of the 28 GHz mmWave channel characteristics for the railway marshaling yard scenario. In this paper, the railway marshaling yard mmWave propagation scenario is deeply analyzed and classified into three typical categories, based on which, a measurement campaign is conducted using an SDR channel sounding system equipped with a 28 GHz mmWave phased-array antenna. A self-developed software under the LabVIEW platform is used to derive the channel parameters. Conclusions on the relationship between the parameters of MPC numbers, time-spread, and received power and position, as well as the impact of typical obstructions such as the Catenary, adjacent locomotives, and buildings are drawn. The statistical results and conclusions of this paper are helpful for facilitating the design and performance evaluation of future mmWave communication systems for railway marshaling yards and can also be further extended and applied to the research of mmWave utilization in 6G and other future communication technologies for more scenarios.
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Meng, Xi, Liyuan Zhong, Dong Zhou e Dacheng Yang. "Co-Channel Coexistence Analysis between 5G IoT System and Fixed-Satellite Service at 40 GHz". Wireless Communications and Mobile Computing 2019 (7 ottobre 2019): 1–9. http://dx.doi.org/10.1155/2019/9790219.
Testo completoAbstract (sommario):
It is a promising way to successfully operate the fifth generation (5G) system with Internet of Things (IoT) in potential mmWave spectrum bands. This paper investigates the intelligent co-channel coexistence between the 5G IoT system and the fixed-satellite service (FSS) system at 40 GHz. The key issue, as identified, is the accurate estimation of interference based on mmWave propagation characteristics. Our simulation results reveal that interference from the 5G IoT system into the FSS ground stations can be kept below the protection threshold by considering different deployment parameters, such as antenna patterns, height of Earth station (ES), and separation distance.
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Li, Yifa, Wei Fan, Huaqiang Gao e Fengchun Zhang. "Experimental Validation and Applications of mm-Wave 8 × 8 Antenna-in-Package (AiP) Array Platform". Electronics 11, n. 23 (6 dicembre 2022): 4055. http://dx.doi.org/10.3390/electronics11234055.
Testo completoAbstract (sommario):
Phased array antennas play an indispensable role in millimeter-wave (mmWave) communications. The Antenna-in-package (AiP) system combines advanced antenna and packaging technology, making it highly valuable for various cellular, radar and automative applications. The benefits it brings in terms of small size, low development costs, low power consumption and fast beam-steering capability further drive the vast deployment of phased array antennas in mmWave systems. In this paper, an 8 × 8 AiP experimental platform is presented and its operating performance is measured and analyzed. Further, two application examples of the AiP are presented, namely, a platform for investigating the phased array calibration performance of different methods, and an AiP-based channel sounder for channel characterization. The performance of the channel sounder is verified by analysing the angle of arrival (AoA), angle of departure (AoD) and propagation delay of the measured dominant propagation components (DPCs).
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Rubio, Lorenzo, Vicent M. Rodrigo Peñarrocha, Marta Cabedo-Fabres, Bernardo Bernardo-Clemente, Juan Reig, Herman Fernández, Jesús R. Pérez, Rafael P. Torres, Luis Valle e Óscar Fernández. "Millimeter-Wave Channel Measurements and Path Loss Characterization in a Typical Indoor Office Environment". Electronics 12, n. 4 (7 febbraio 2023): 844. http://dx.doi.org/10.3390/electronics12040844.
Testo completoAbstract (sommario):
In this paper, a path loss characterization at millimeter-wave (mmWave) frequencies is performed in a typical indoor office environment. Path loss results were derived from propagation channel measurements collected in the 25–40 GHz frequency band, in both line-of-sight (LOS) and obstructed-LOS (OLOS) propagation conditions. The channel measurements were performed using a frequency-domain channel sounder, which integrates an amplified radio over fiber (RoF) link to avoid the high losses at mmWave. The path loss was analyzed in the 26 GHz, 28 GHz, 33 GHz and 38 GHz frequency bands through the close-in free space reference distance (CI) and the floating-intercept (FI) models. These models take into account the distance dependence of the path loss for a single frequency. Nevertheless, to jointly study the distance and frequency dependence of the path loss, multi-frequency models were considered. The parameters of the ABG (A-alpha, B-beta and G-gamma) and the close-in free space reference distance with frequency path loss exponent (CIF) models were derived from the channel measurements in the whole 25–40 GHz band under the minimum mean square error (MMSE) approach. The results show that, in general, there is some relationship between the model parameters and the frequency. Path loss exponent (PLE) values smaller than the theoretical free space propagation were obtained, showing that there are a waveguide effect and a constructive interference of multipath components (MPCs). Since the measurements were obtained in the same environment and with the same configuration and measurement setup, it is possible to establish realistic comparisons between the model parameters and the propagation behavior at the different frequencies considered. The results provided here allow us to have a better knowledge of the propagation at mmWave frequencies and may be of interest to other researchers in the simulation and performance evaluation of future wireless communication systems in indoor hotspot environments.
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Begishev, Vyacheslav, Dmitri Moltchanov, Anna Gaidamaka e Konstantin Samouylov. "Closed-Form UAV LoS Blockage Probability in Mixed Ground- and Rooftop-Mounted Urban mmWave NR Deployments". Sensors 22, n. 3 (27 gennaio 2022): 977. http://dx.doi.org/10.3390/s22030977.
Testo completoAbstract (sommario):
Unmanned aerial vehicles (UAV) are envisioned to become one of the new types of fifth/sixth generation (5G/6G) network users. To support advanced services for UAVs such as video monitoring, one of the prospective options is to utilize recently standardized New Radio (NR) technology operating in the millimeter-wave (mmWave) frequency band. However, blockage of propagation paths between NR base stations (BS) and UAV by buildings may lead to frequent outage situations. In our study, we use the tools of integral geometry to characterize connectivity properties of UAVs in terrestrial urban deployments of mmWave NR systems using UAV line-of-sight (LoS) blockage probability as the main metric of interest. As opposed to other studies, the use of the proposed approach allows us to get closed-form approximation for LoS blockage probability as a function of city and network deployment parameters. As one of the options to improve connectivity we also consider rooftop-mounted mmWave BSs. Our results illustrate that the proposed model provides an upper bound on UAV LoS blockage probability, and this bound becomes more accurate as the density of mmWave BS in the area increases. The closed-form structure allows for identifying of the street width, building block and BS heights, and UAV altitude as the parameters providing the most impact on the considered metric. We show that rooftop-mounted mmWave BSs allow for the drastic improvement of LoS blockage probability, i.e., depending on the system parameters the use of one rooftop-mounted mmWave BS is equivalent to 6–12 ground-mounted mmWave BSs. Out of all considered deployment parameters the street width is the one most heavily affecting the UAV LoS blockage probability. Specifically, the deployment with street width of 20 m is characterized by 50% lower UAV LoS blockage probability as compared to the one with 10 m street width.
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Zhong, Zhimeng, Jianyao Zhao e Chao Li. "Outdoor-to-Indoor Channel Measurement and Coverage Analysis for 5G Typical Spectrums". International Journal of Antennas and Propagation 2019 (16 settembre 2019): 1–10. http://dx.doi.org/10.1155/2019/3981678.
Testo completoAbstract (sommario):
The fifth-generation (5G) mobile communications system will adopt the millimeter wave (mmWave) band for outdoor-to-indoor (O2I) coverage to achieve ultrahigh data rate. However, it is a challenging task because of the large path loss and almost total blocking by building walls. In this work, we performed extensive measurements on the O2I propagation at 3.5, 4.9, and 28 GHz simultaneously by using a multiband channel sounder. We captured the path loss distribution and angular power arrival profiles. We also measured the penetration loss at 28 GHz through different kinds of glass windows. The widely adopted ordinary glass windows introduce the penetration loss of 3 to 12 dB that is acceptable and makes mmWave O2I coverage feasible. But the low-emissivity (low-E) windows that will be more popular in the future introduce 10 dB higher loss. The measurement results in this work can help analyse and anticipate the O2I coverage by mmWave, which is important for the design and deployment of the 5G network.
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Md Jizat, Noorlindawaty, Zubaida Yusoff, Azah Syafiah Mohd Marzuki, Norsiha Zainudin e Yoshihide Yamada. "Insertion Loss and Phase Compensation Using a Circular Slot Via-Hole in a Compact 5G Millimeter Wave (mmWave) Butler Matrix at 28 GHz". Sensors 22, n. 5 (26 febbraio 2022): 1850. http://dx.doi.org/10.3390/s22051850.
Testo completoAbstract (sommario):
Fifth generation (5G) technology aims to provide high peak data rates, increased bandwidth, and supports a 1 millisecond roundtrip latency at millimeter wave (mmWave). However, higher frequency bands in mmWave comes with challenges including poor propagation characteristics and lossy structure. The beamforming Butler matrix (BM) is an alternative design intended to overcome these limitations by controlling the phase and amplitude of the signal, which reduces the path loss and penetration losses. At the mmWave, the wavelength becomes smaller, and the BM planar structure is intricate and faces issues of insertion losses and size due to the complexity. To address these issues, a dual-layer substrate is connected through the via, and the hybrids are arranged side by side. The dual-layer structure circumvents the crossover elements, while the strip line, hybrids, and via-hole are carefully designed on each BM element. The internal design of BM features a compact size and low-profile structure, with dimensions of 23.26 mm × 28.92 mm (2.17 λ0 × 2.69 λ0), which is ideally suited for the 5G mmWave communication system. The designed BM measured results show return losses, Sii and Sjj, of less than −10 dB, transmission amplitude of −8 ± 2 dB, and an acceptable range of output phase at 28 GHz.
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Khawaja, Wahab, Ozgur Ozdemir e Ismail Guvenc. "Channel Prediction for mmWave Ground-to-Air Propagation Under Blockage". IEEE Antennas and Wireless Propagation Letters 20, n. 8 (agosto 2021): 1364–68. http://dx.doi.org/10.1109/lawp.2021.3078268.
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Qamar, Faizan, Mhd Nour Hindia, Tharek Abd Rahman, Rosilah Hassan, Kaharudin Dimyati e Quang Ngoc Nguyen. "Propagation Characterization and Analysis for 5G mmWave Through Field Experiments". Computers, Materials & Continua 68, n. 2 (2021): 2249–64. http://dx.doi.org/10.32604/cmc.2021.017198.
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He, Danping, Bo Ai, Ke Guan, Juan Moreno Garcia-Loygorri, Li Tian, Zhangdui Zhong e Andrej Hrovat. "Influence of Typical Railway Objects in a mmWave Propagation Channel". IEEE Transactions on Vehicular Technology 67, n. 4 (aprile 2018): 2880–92. http://dx.doi.org/10.1109/tvt.2017.2782268.
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Bedda Zekri, Abdelbasset, e Riadh Ajgou. "Towards 5G: A study of the impact of antenna polarization on statistical channel modeling". Sustainable Engineering and Innovation 4, n. 1 (30 giugno 2022): 97–103. http://dx.doi.org/10.37868/sei.v4i1.id168.
Testo completoAbstract (sommario):
The millimetre wave (mmWave) is alleged as an important element invention to respond to the rapid increase in wireless demand for mobile traffic using its huge bandwidth. However, channel modeling remains difficult due to its high dependence on weather conditions and the positioning of the antenna for communication in direct visibility line-of-sight (LOS). Co-polarization and cross-polarization (X-pol) are two main events in the direction of the radiation element for wave transmission; where the wanted direction of wave transmission denotes the co-pol and the orthogonal propagation of the intended direction represents X-pol. This work investigates the effect of the polarization on a statistical channel modeling at 28 GHz, 38 GHz & 73 GHz mmWave channel using NYUSIM Model.
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Domingo, Mari Carmen. "Power Allocation and Energy Cooperation for UAV-Enabled MmWave Networks: A Multi-Agent Deep Reinforcement Learning Approach". Sensors 22, n. 1 (30 dicembre 2021): 270. http://dx.doi.org/10.3390/s22010270.
Testo completoAbstract (sommario):
Unmanned Aerial Vehicle (UAV)-assisted cellular networks over the millimeter-wave (mmWave) frequency band can meet the requirements of a high data rate and flexible coverage in next-generation communication networks. However, higher propagation loss and the use of a large number of antennas in mmWave networks give rise to high energy consumption and UAVs are constrained by their low-capacity onboard battery. Energy harvesting (EH) is a viable solution to reduce the energy cost of UAV-enabled mmWave networks. However, the random nature of renewable energy makes it challenging to maintain robust connectivity in UAV-assisted terrestrial cellular networks. Energy cooperation allows UAVs to send their excessive energy to other UAVs with reduced energy. In this paper, we propose a power allocation algorithm based on energy harvesting and energy cooperation to maximize the throughput of a UAV-assisted mmWave cellular network. Since there is channel-state uncertainty and the amount of harvested energy can be treated as a stochastic process, we propose an optimal multi-agent deep reinforcement learning algorithm (DRL) named Multi-Agent Deep Deterministic Policy Gradient (MADDPG) to solve the renewable energy resource allocation problem for throughput maximization. The simulation results show that the proposed algorithm outperforms the Random Power (RP), Maximal Power (MP) and value-based Deep Q-Learning (DQL) algorithms in terms of network throughput.
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Abdulwahid, Maan M., e Noraldeen B. Mohammed Wasel. "Optimum AP Estimation Location for the communication of different mmWave bands". Informatica : Journal of Applied Machines Electrical Electronics Computer Science and Communication Systems 01, n. 01 (1 dicembre 2020): 44–53. http://dx.doi.org/10.47812/ijamecs2010107.
Testo completoAbstract (sommario):
Millimeter wave (mmWave) has been known to be the most promising technology for the future of wireless communication. It uses directional antenna for both transmitters and receivers to minimize its higher attenuation characteristics. Different localization approaches take the advantages of these directionality features in mmWave frequencies for different indoor environment. As a result, understanding the best position for AP's implementation has a huge effect on enhancing certain areas of network activity, maintenance, and coverage. In addition, establish the behavioral features of the wireless network. For localization purposes, the most used method was based on calculations of obtained signal intensity (RSS), which is commonly used in the wireless network. As well as it can be easily accessed from different operating systems. In this paper, we proposed an optimal AP localization algorithm based on RSS measurement obtained from different received points and by using mmWave bands of 28 and 39 GHz. This algorithm works as a complementary to the results obtained from 3D Ray tracing model based wireless InSite software. Four AP locations per each selected mmWave band have been included for algorithm investigation. Results obtained illustrate utility in selecting the appropriate position for the implementation of AP and based on the estimation of various parameters by the algorithm presented. The effects of different building materials and frequency sensitivity materials on signal propagation have been considered with specifying the optimum location for deploying AP. In addition, in this article, a channel characterized based on path losses was obtained for each AP position in each mmWave band as a validation of the algorithm's selection of the optimum location.
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Sarker, Md Abdul Latif, Woosung Son e Dong Seog Han. "RIS-Assisted Hybrid Beamforming and Connected User Vehicle Localization for Millimeter Wave MIMO Systems". Sensors 23, n. 7 (3 aprile 2023): 3713. http://dx.doi.org/10.3390/s23073713.
Testo completoAbstract (sommario):
A reconfigurable intelligent surface (RIS) is a type of metasurface that can dynamically control the reflection and transmission of electromagnetic waves, such as radio waves, by changing its physical properties. Recently, RISs have played an important role in intelligently reshaping wireless propagation environments to improve the received signal gain as well as spectral efficiency performance. In this paper, we consider a millimeter wave (mmWave) vehicle-to-vehicle (V2V) multiple-input multiple-output (MIMO) system in which, an RIS is deployed to aid downlink V2V data transmission. In particular, the line-of-sight path of the mmWave system is affected by blockages, resulting in higher signaling overhead. Thus, the system performance may suffer due to interruptions caused by static or mobile blockers, such as buildings, trees, vehicles, and pedestrians. In this paper, we propose an RIS-assisted hybrid beamforming scheme for blockage-aware mmWave V2V MIMO systems to increase communication service coverage. First, we propose a conjugate gradient and location-based hybrid beamforming (CG-LHB) algorithm to solve the user sub-rate maximization problem. We then propose a double-step iterative algorithm that utilizes an error covariance matrix splitting method to minimize the effect of location error on the passive beamforming. The proposed algorithms perform quite well when the channel uncertainty is smaller than 10%. Finally, the simulation results validate the proposed CG-LHB algorithm in terms of the RIS-assisted equivalent channel for mmWave V2V MIMO communications.
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Ren, Ming-Hao, Xi Liao, Jihua Zhou, Yang Wang, Yu Shao, Shasha Liao e Jie Zhang. "Diffuse Scattering Directive Model Parameterization Method for Construction Materials at mmWave Frequencies". International Journal of Antennas and Propagation 2020 (22 dicembre 2020): 1–9. http://dx.doi.org/10.1155/2020/1583854.
Testo completoAbstract (sommario):
The determination for diffuse scattering model parameters is of critical importance to improve the accuracy of prediction and analysis for millimeter-wave radio propagation. In this paper, a reliable parameterization method with a simplified tuning procedure for a diffuse scattering model is proposed and validated based on measurements and ray-tracing simulations. Typical construction materials are measured from 40 GHz to 50 GHz, and the complex permittivity is estimated by the propagation coefficients match method. The directive model, which can better characterize the scattering patterns of construction materials in this paper, is adopted to calibrate the ray-tracing simulation. Model parameterization is performed and simulated results with the optimal model parameters show distinct accuracy improvement.
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Prosvirov, Vladislav, Amjad Ali, Abdukodir Khakimov e Yevgeni Koucheryavy. "Spatio-Temporal Coherence of mmWave/THz Channel Characteristics and Their Forecasting Using Video Frame Prediction Techniques". Mathematics 11, n. 17 (23 agosto 2023): 3634. http://dx.doi.org/10.3390/math11173634.
Testo completoAbstract (sommario):
Channel state information in millimeter wave (mmWave) and terahertz (THz) communications systems is vital for various tasks ranging from planning the optimal locations of BSs to efficient beam tracking mechanisms to handover design. Due to the use of large-scale phased antenna arrays and high sensitivity to environmental geometry and materials, precise propagation models for these bands are obtained via ray-tracing modeling. However, the propagation conditions in mmWave/THz systems may theoretically change at very small distances, that is, 1 mm–1 μm, which requires extreme computational effort for modeling. In this paper, we first will assess the effective correlation distances in mmWave/THz systems for different outdoor scenarios, user mobility patterns, and line-of-sight (LoS) and non-LoS (nLoS) conditions. As the metrics of interest, we utilize the angle of arrival/departure (AoA/AoD) and path loss of the first few strongest rays. Then, to reduce the computational efforts required for the ray-tracing procedure, we propose a methodology for the extrapolation and interpolation of these metrics based on the convolutional long short-term memory (ConvLSTM) model. The proposed methodology is based on a special representation of the channel state information in a form suitable for state-of-the-art video enhancement machine learning (ML) techniques, which allows for the use of their powerful prediction capabilities. To assess the prediction performance of the ConvLSTM model, we utilize precision and recall as the main metrics of interest. Our numerical results demonstrate that the channel state correlation in AoA/AoD parameters is preserved up until approximately 0.3–0.6 m, which is 300–600 times larger than the wavelength at 300 GHz. The use of a ConvLSTM model allows us to accurately predict AoA and AoD angles up to the 0.6 m distance with AoA being characterized by a higher mean squared error (MSE). Our results can be utilized to speed up ray-tracing simulations by selecting the grid step size, resulting in the desired trade-off between modeling accuracy and computational time. Additionally, it can also be utilized to improve beam tracking in mmWave/THz systems via a selection of the time step between beam realignment procedures.
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Celaya-Echarri, Mikel, Leyre Azpilicueta, Fidel Alejandro Rodríguez-Corbo, Peio Lopez-Iturri, Victoria Ramos, Mohammad Alibakhshikenari, Raed M. Shubair e Francisco Falcone. "Towards Environmental RF-EMF Assessment of mmWave High-Node Density Complex Heterogeneous Environments". Sensors 21, n. 24 (16 dicembre 2021): 8419. http://dx.doi.org/10.3390/s21248419.
Testo completoAbstract (sommario):
The densification of multiple wireless communication systems that coexist nowadays, as well as the 5G new generation cellular systems advent towards the millimeter wave (mmWave) frequency range, give rise to complex context-aware scenarios with high-node density heterogeneous networks. In this work, a radiofrequency electromagnetic field (RF-EMF) exposure assessment from an empirical and modeling approach for a large, complex indoor setting with high node density and traffic is presented. For that purpose, an intensive and comprehensive in-depth RF-EMF E-field characterization study is provided in a public library study case, considering dense personal mobile communications (5G FR2 @28 GHz) and wireless 802.11ay (@60 GHz) data access services on the mmWave frequency range. By means of an enhanced in-house deterministic 3D ray launching (3D-RL) simulation tool for RF-EMF exposure assessment, different complex heterogenous scenarios of high complexity are assessed in realistic operation conditions, considering different user distributions and densities. The use of directive antennas and MIMO beamforming techniques, as well as all the corresponding features in terms of radio wave propagation, such as the body shielding effect, dispersive material properties of obstacles, the impact of the distribution of scatterers and the associated electromagnetic propagation phenomena, are considered for simulation. Discussion regarding the contribution and impact of the coexistence of multiple heterogeneous networks and services is presented, verifying compliance with the current established international regulation limits with exposure levels far below the aforementioned limits. Finally, the proposed simulation technique is validated with a complete empirical campaign of measurements, showing good agreement. In consequence, the obtained datasets and simulation estimations, along with the proposed RF-EMF simulation tool, could be a reference approach for the design, deployment and exposure assessment of the current and future wireless communication technologies on the mmWave spectrum, where massive high-node density heterogeneous networks are expected.
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De Beelde, Brecht, Mike Vantorre, German Castellanos, Mario Pickavet e Wout Joseph. "MmWave Physical Layer Network Modeling and Planning for Fixed Wireless Access Applications". Sensors 23, n. 4 (17 febbraio 2023): 2280. http://dx.doi.org/10.3390/s23042280.
Testo completoAbstract (sommario):
The large bandwidths that are available at millimeter-wave frequencies enable fixed wireless access (FWA) applications, in which fixed point-to-point wireless links are used to provide internet connectivity. In FWA networks, a wireless mesh is created and data are routed from the customer premises equipment (CPE) towards the point of presence (POP), which is the interface with the wired internet infrastructure. The performance of the wireless links depends on the radio propagation characteristics, as well as the wireless technology that is used. The radio propagation characteristics depend on the environment and on the considered frequency. In this work, we analyzed the network characteristics of FWA networks using radio propagation models for different wireless technologies using millimeter-wave (mmWave) frequencies of 28 GHz, 60 GHz, and 140 GHz. Different scenarios and environments were considered, and the influence of rain, vegetation, and the number of subscribers was investigated. A network planning algorithm is presented that defines a route for each CPE towards the POP based on a predefined location of customer devices and considering the available capacity of the wireless links. Rain does not have a considerable effect on the system capacity. Even though the higher frequencies exhibit a larger path loss, resulting in a lower power of the received signal, the larger bandwidths enable a higher channel capacity.
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Kamboh, Usman Rauf, Muhammad Rehman Shahid, Hamza Aldabbas, Ammar Rafiq, Bader Alouffi, Muhammad Asif Habib e Ubaid Ullah. "Radio Network Forensic with mmWave Using the Dominant Path Algorithm". Security and Communication Networks 2022 (12 gennaio 2022): 1–15. http://dx.doi.org/10.1155/2022/9692892.
Testo completoAbstract (sommario):
For the last two decades, cybercrimes are growing on a daily basis. To track down cybercrimes and radio network crimes, digital forensic for radio networks provides foundations. The data transfer rate for the next-generation wireless networks would be much greater than today’s network in the coming years. The fifth-generation wireless systems are considering bands beyond 6 GHz. The network design of the next-generation wireless systems depends on propagation characteristics, frequency reuse, and bandwidth variation. This article declares the channel’s propagation characteristics of both line of sight (LoS) and non-LOS (NLoS) to construct and detect the path of rays coming from anomalies. The simulations were carried out to investigate the diffraction loss (DL) and frequency drop (FD). Indoor and outdoor measurements were taken with the omnidirectional circular dipole antenna with a transmitting frequency of 28 GHz and 60 GHz to compare the two bands of the 5th generation. Millimeter-wave communication comes with a higher constraint for implementing and deploying higher losses, low diffractions, and low signal penetrations for the mentioned two bands. For outdoor, a MATLAB built-in 3D ray tracing algorithm is used while for an indoor office environment, an in-house algorithmic simulator built using MATLAB is used to analyze the channel characteristics.
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Comisso, Massimiliano, Giulia Buttazzoni, Stefano Pastore, Francesca Vatta e Fulvio Babich. "3D Poisson-Based Neighborhood Capacity Analysis for Millimeter Wave Communications". Sensors 22, n. 6 (8 marzo 2022): 2098. http://dx.doi.org/10.3390/s22062098.
Testo completoAbstract (sommario):
This paper proposes a theoretical model for evaluating the capacity of a millimeter wave (mmWave) source destination link when the nodes are distributed according to a three-dimensional (3D) homogeneous Poisson point process. In the presented analysis, different from the existing approaches, the destination lies in an arbitrary location with respect to the source; thus, the link performance can be evaluated for a neighbor of any order. Moreover, the developed model relies on a realistic propagation environment, characterized by path loss attenuation and shadowing in line of sight (LoS), non-LoS, and outage link state conditions. The derived formulas, which are calculated in closed-form and validated by independent Monte Carlo simulations, are used to investigate the influence of the intensity parameter, of the antenna gain, and of the mmWave frequency band on the link capacity for any possible neighbor in a practical 3D scenario.
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Jaksic, Dejan, Risto Bojovic, Petar Spalevic, Dusan Stefanovic e Slavisa Trajkovic. "Performance Analysis of 5G Transmission over Fading Channels with Random IG Distributed LOS Components". International Journal of Antennas and Propagation 2017 (2017): 1–4. http://dx.doi.org/10.1155/2017/4287586.
Testo completoAbstract (sommario):
Mathematical modelling of the behavior of the radio propagation at mmWave bands is crucial to the development of transmission and reception algorithms of new 5G systems. In this study we will model 5G propagation in nondeterministic line-of-sight (LOS) conditions, when the random nature of LOS component ratio will be observed as Inverse Gamma (IG) distributed process. Closed-form expressions will be presented for the probability density function (PDF) and cumulative distribution function (CDF) of such random process. Further, closed-form expressions will be provided for important performance measures such as level crossing rate (LCR) and average fade duration (AFD). Capitalizing on proposed expressions, LCR and AFD will be discussed in the function of transmission parameters.
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Aldossari, Saud Alhajaj. "Predicting Path Loss of an Indoor Environment Using Artificial Intelligence in the 28-GHz Band". Electronics 12, n. 3 (18 gennaio 2023): 497. http://dx.doi.org/10.3390/electronics12030497.
Testo completoAbstract (sommario):
The propagation of signal and its strength in an indoor area have become crucial in the era of fifth-generation (5G) and beyond-5G communication systems, which use high bandwidth. High millimeter wave (mmWave) frequencies present a high signal loss and low signal strength, particularly during signal propagation in indoor areas. It is considerably difficult to design indoor wireless communication systems through deterministic modeling owing to the complex nature of the construction materials and environmental changes caused by human interactions. This study presents a methodology of data-driven techniques that will be applied to predict path loss using artificial intelligence. The proposed methodology enables the prediction of signal loss in an indoor environment with an accuracy of 97.4%.
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Yu, Xiaolu, Hang Li, Jian Andrew Zhang, Xiaojing Huang e Zhiqun Cheng. "Enhanced Angle-of-Arrival and Polarization Parameter Estimation Using Localized Hybrid Dual-Polarized Arrays". Sensors 22, n. 14 (12 luglio 2022): 5207. http://dx.doi.org/10.3390/s22145207.
Testo completoAbstract (sommario):
The millimeter wave (mmWave) channel is dominated by line-of-sight propagation. Therefore, the acquisition of angle-of-arrival (AoA) and polarization state of the wave is of great significance to the receiver. In this paper, we investigate AoA and polarization estimation in a mmWave system employing dual-polarized antenna arrays. We propose an enhanced AoA estimation method using a localized hybrid dual-polarized array for a polarized mmWave signal. The use of dual-polarized arrays greatly improves the calibration of differential signals and the signal-to-noise ratio (SNR) of the phase offset estimation between adjacent subarrays. Given the estimated phase offset, an initial AoA estimate can be obtained, and is then used to update the phase offset estimation. This leads to a recursive estimation with improved accuracy. We further propose an enhanced polarization estimation method, which uses the power of total received signals at dual-polarized antennas to compute the cross-correlation-to-power ratio instead of using only one axis dipole. Thus the accuracy of polarization parameter estimation is improved. We also derive a closed-form expression for mean square error lower bounds of AoA estimation and present an average SNR analysis for polarization estimation performance. Simulation results demonstrate the superiority of the enhanced AoA and polarization parameter estimation methods compared to the state of the art.
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Wolf, Marius, Kai Werum, Wolfgang Eberhardt, Thomas Günther e André Zimmermann. "Injection Compression Molding of LDS-MID for Millimeter Wave Applications". Journal of Manufacturing and Materials Processing 7, n. 5 (13 ottobre 2023): 184. http://dx.doi.org/10.3390/jmmp7050184.
Testo completoAbstract (sommario):
LDS-MIDs (laser direct structured mechatronic integrated devices) are 3D (three-dimensional) circuit carriers that are used in many applications with a focus on antennas. However, thanks to the rising frequencies of HF (high-frequency) systems in 5G and radar applications up to the mmWave (millimeter wave) region, the requirements regarding the geometrical accuracy and minimal wall thicknesses for proper signal propagation in mmWave circuits became more strict. Additionally, interest in combining those with 3D microstructures like trenches or bumps for optimizing transmission lines and subsequent mounting processes is rising. The change from IM (injection molding) to ICM (injection compression molding) could offer a solution for improving the 3D geometries of LDS-MIDs. To enhance the scientific insight into this process variant, this paper reports on the manufacturing of LDS-MIDs for mmWave applications. Measurements of the warpage, homogeneity of local wall thicknesses, and replication accuracy of different trenches and bumps for mounting purposes are presented. Additionally, the effect of a change in the manufacturing process from IM to ICM regarding the dielectric properties of the used thermoplastics is reported as well as the influence of ICM on the properties of LDS metallization—in particular the metallization roughness and adhesion strength. This paper is then concluded by reporting on the HF performance of CPWs (coplanar waveguides) on LDS-MIDs in comparison to an HF-PCB.
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Han, Tian, Davood Shojaei, Paul Fitzpatrick, Taka Sakurai e Jamie Evans. "Urban 5G MmWave Networks: Line-of-Sight Probabilities and Optimal Site Locations". Journal of Telecommunications and the Digital Economy 11, n. 1 (31 marzo 2023): 107–30. http://dx.doi.org/10.18080/jtde.v11n1.640.
Testo completoAbstract (sommario):
In this work, we implemented line-of-sight (LoS) ray tracing functionality to investigate problems in millimetre-wave propagation modelling and network planning in 3D city model environments. First, we validated an existing LoS propagation probability model expressed as an exponential rule with the link distance. By fitting ray tracing simulation results under different scenarios to the model, the relationships between key parameters in the model and factors including the building density and the transmitter height were qualitatively analysed. Next, we developed a network planning framework for a multi-hop outdoor urban network by formulating a mixed-integer linear programming problem which minimises the overall deployment cost through optimal site selection. Taking the sets of potential site locations and potential links as inputs, we selected a subset of the sites that comprise a tree-structured network that satisfies all the user demands at a minimum deployment cost. We also analysed the time required for solving this optimisation problem in order to provide a prediction of the execution time for larger-sized problems.
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Kabalci, Yasin, e Muhammad Ali. "Improved Hybrid Precoder Design for Secure mmWave MIMO Communications". Elektronika ir Elektrotechnika 26, n. 4 (7 agosto 2020): 72–77. http://dx.doi.org/10.5755/j01.eie.26.4.25857.
Testo completoAbstract (sommario):
Key challenges of emerging mobile communication systems are to provide higher data rates, diverse device connectivity, low latency, higher system capacity, and low energy consumption. The communication systems exploiting the millimeter-wave (mmWave) band are realized to resolve thereof inevitable issues. However, security is considered as one of the challenging issues in mmWave communication in addition to unavoidable problems (e.g., propagation loss, penetration loss, and fading). This study aims to construct efficient secure hybrid precoder with low-resolution phase shifters that can protect legitimate information from eavesdropping by employing coordinated analog precoder and combiner algorithms and improve the secrecy rate. Moreover, in order to further enhance the secrecy rate, hybrid precoder are obtained using an efficient channel. This work compares its results with the recent approach reported in the literature, which indicates that our proposed model outperforms at high signal-to-noise ratio (SNR) values, while our model provides similar performance at low SNR values. Simulation studies also confirm the effectiveness of the proposed hybrid precoder to achieve maximum secrecy rate.
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Majed, Mohammed Bahjat, Tharek Abd Rahman, Omar Abdul Aziz, Mohammad Nour Hindia e Effariza Hanafi. "Channel Characterization and Path Loss Modeling in Indoor Environment at 4.5, 28, and 38 GHz for 5G Cellular Networks". International Journal of Antennas and Propagation 2018 (20 settembre 2018): 1–14. http://dx.doi.org/10.1155/2018/9142367.
Testo completoAbstract (sommario):
The current propagation models used for frequency bands less than 6 GHz are not appropriate and cannot be applied for path loss modeling and channel characteristics for frequency bands above 6 GHz millimeter wave (mmWave) bands, due to the difference of signal propagation characteristics between existing frequency bands and mmWave frequency bands. Thus, extensive studies on channel characterization and path loss modeling are required to develop a general and appropriate channel model that can be suitable for a wide range of mmWave frequency bands in its modeling parameter. This paper presents a study of well-known channel models for an indoor environment on the 4.5, 28, and 38 GHz frequency bands. A new path loss model is proposed for the 28 GHz and 38 GHz frequency bands. Measurements for the indoor line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios were taken every meter over a separation distance of 23 m between the TX and RX antenna locations to compare the well-known and the new large-scale generic path loss models. This measurement was conducted in a new wireless communication center WCC block P15a at Universiti Teknologi Malaysia UTM Johor, Malaysia, and the results were analyzed based on the well-known and proposed path loss models for single-frequency and multifrequency models and for directional and omnidirectional path loss models. Results show that the large-scale path loss over distance could be modeled better with good accuracy by using the simple proposed model with one parameter path loss exponent PLE (n) that is physically based to the transmitter power, rather than using the well-known models that have no physical base to the transmitted power, more complications (require more parameters), and lack of anticipation when explaining model parameters. The PLE values for the LOS scenario were 0.92, 0.90, and 1.07 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 28 GHz frequency and were 2.30, 2.24, and 2.40 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 38 GHz frequency.
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Mehdi Haghshenas, Francesco Linsalata, Luca Barbieri, Mattia Brambilla, Monica Nicoli e Maurizio Magarini. "Analysis of spatial scheduling in downlink vehicular communications: Sub-6 GHz vs mmWave". ITU Journal on Future and Evolving Technologies 3, n. 2 (30 settembre 2022): 523–34. http://dx.doi.org/10.52953/gewx7355.
Testo completoAbstract (sommario):
Vehicular communications are gaining a lot of attention for the delivery of enhanced mobility services that require multi-Gbps and low latency connections. In this paper, we focus on Infrastructure-to-Vehicle (I2V) communications where a gNB has to assign spatial resources to a number of connected vehicle users. To efficiently manage the scheduling, we compare the Zero Forcing (ZF) and Maximum Ratio (MR) precoding strategies by evaluating the effect of shifting from sub-6 GHz to millimeter wave (mmWave) frequencies in urban and highway mobility scenarios. We analyze the impact of the geometry of the environment and propagation characteristics at different frequencies in terms of number of users that can be served and spectral efficiency. To model the I2V channel, we integrate realistic traffic conditions generated by SUMO into an accurate channel model based on ray tracing software by WirelessInsite. By numerical results we demonstrate the degradation at mmWave compared to sub-6 GHz on the multiplexing gain. We show the higher efficiency of ZF compared to MR as the former is not limited by inter-user interference, especially in urban scenarios where the number of distinctive eigendirections in space is limited. On the other hand, highway mobility has a more uniform distribution of vehicles that can be conveniently explored by the ZF scheduling to serve more users. Lastly, we show the benefits of adopting a higher number of transmit antennas at mmWave jointly with efficient scheduling to achieve higher spectral efficiency.
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Iwabuchi, Masashi, Yoghitha Ramamoorthi e Kei Sakaguchi. "User-Driven Relay Beamforming for mmWave Massive Analog-Relay MIMO". Sensors 23, n. 2 (16 gennaio 2023): 1034. http://dx.doi.org/10.3390/s23021034.
Testo completoAbstract (sommario):
Sixth-generation mobile communication (6G) aims to further improve capacity and reliability by controlling the radio propagation environment. Millimeter wave (mmWave) high-frequency band communication offers large bandwidth at the cost of high attenuation, even for smaller distances. Due to this, fewer multiple input multiple outputs (MIMO) multiplexing is possible at the base station (BS). Distributed analog relay nodes with beamforming capability improve the received power and MIMO multiplexing of mmWave communication. Due to limited signal processing, the analog relay node cannot perform beam search and tracking using these mmWave reference signals. The beam search and tracking are possible at BS or user equipment at the cost of increased control overhead. To reduce this overhead and provide relay-based 6G communication, we propose user-driven relay beamforming methods which can obtain the benefits of a massive analog relay MIMO. Assuming vehicular-to-everything (V2X) as a 6G application, we considered a relay-beam control method that uses the user information (location, velocity, acceleration, and direction of the terminal) contained in intelligent transport systems (ITS) messages called Cooperative Awareness Message (CAM). Simulation results show that the proposed method significantly reduces the overhead and the obtains benefits of the massive analog-relay MIMO. Furthermore, the accuracy of CAM’s location information, the control period, and the effects of UE mobility are evaluated and presented. The results also show that the proposed method can work effectively in future V2X applications.
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Rafiq, Ahsan, Reem Alkanhel, Mohammed Saleh Ali Muthanna, Evgeny Mokrov, Ahmed Aziz e Ammar Muthanna. "Intelligent Resource Allocation Using an Artificial Ecosystem Optimizer with Deep Learning on UAV Networks". Drones 7, n. 10 (3 ottobre 2023): 619. http://dx.doi.org/10.3390/drones7100619.
Testo completoAbstract (sommario):
An Unmanned Aerial Vehicle (UAV)-based cellular network over a millimeter wave (mmWave) frequency band addresses the necessities of flexible coverage and high data rate in the next-generation network. But, the use of a wide range of antennas and higher propagation loss in mmWave networks results in high power utilization and UAVs are limited by low-capacity onboard batteries. To cut down the energy cost of UAV-aided mmWave networks, Energy Harvesting (EH) is a promising solution. But, it is a challenge to sustain strong connectivity in UAV-based terrestrial cellular networks due to the random nature of renewable energy. With this motivation, this article introduces an intelligent resource allocation using an artificial ecosystem optimizer with a deep learning (IRA-AEODL) technique on UAV networks. The presented IRA-AEODL technique aims to effectually allot the resources in wireless UAV networks. In this case, the IRA-AEODL technique focuses on the maximization of system utility over all users, combined user association, energy scheduling, and trajectory design. To optimally allocate the UAV policies, the stacked sparse autoencoder (SSAE) model is used in the UAV networks. For the hyperparameter tuning process, the AEO algorithm is used for enhancing the performance of the SSAE model. The experimental results of the IRA-AEODL technique are examined under different aspects and the outcomes stated the improved performance of the IRA-AEODL approach over recent state of art approaches.
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Duan, Fei, Yuhao Guo, Zenghui Gu, Yanlong Yin, Yixin Wu e Teyan Chen. "Optical Beamforming Networks for Millimeter-Wave Wireless Communications". Applied Sciences 13, n. 14 (19 luglio 2023): 8346. http://dx.doi.org/10.3390/app13148346.
Testo completoAbstract (sommario):
With the rapid data growth driven by smart phone, high-definition television and virtual reality/augmented reality devices and so on, the launched 5G and upcoming 6G wireless communications tend to utilize millimeter wave (mmWave) to achieve broad bandwidth. In order to compensate for the high propagation loss in mmWave wireless communications and track the moving users, beamforming and beamsteering are indispensable enabling technologies. These have promising potential to be realized through the use of optical beamforming networks (OBFNs) that have a wider bandwidth and smaller size, lower power consumption, and lower loss compared to those of their electric counterparts. In this paper, we systematically review various OBFN architectures using true time delays and optical phase shifters, as well as discuss performances of different architectures, scalable technologies that promote the advancement of OBFNs, and the application potentials of OBFNs. Two-dimensional OBFNs with discrete components or integrated optical devices have been elaborated, in addition to one-dimensional architectures. Moreover, the state-of-the-art technologies relative to reducing the size, loss and nonlinearity of OBFNs have also been discussed here.
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Zhang, Ruonan, Yuliang Zhou, Xiaofeng Lu, Chang Cao e Qi Guo. "Antenna Deembedding for mmWave Propagation Modeling and Field Measurement Validation at 73 GHz". IEEE Transactions on Microwave Theory and Techniques 65, n. 10 (ottobre 2017): 3648–59. http://dx.doi.org/10.1109/tmtt.2017.2743702.
Testo completo
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Aldalbahi, Adel, Farzad Shahabi e Mohammed Jasim. "Instantaneous Beam Prediction Scheme against Link Blockage in mmWave Communications". Applied Sciences 11, n. 12 (17 giugno 2021): 5601. http://dx.doi.org/10.3390/app11125601.
Testo completoAbstract (sommario):
Millimeter wave (mmWave) bands formulate the standalone (SA) operation mode in the new radio (NR) access technology of 5G systems. These bands rely on beamforming architectures to aggregate antenna array gains that compensate for dynamic channel fluctuations and propagation impairments. However, beamforming results in directional transmission and reception, thus resulting in beam management challenges, foremost initial access, handover, and beam blockage recovery. Here, beam establishment and maintenance must feature ultra-low latencies in the control and data planes to meet network specifications and standardization. Presently, existing schemes rely on arrays redundancy, multi-connectivity, such as dual-beam and carrier aggregation, and out-of-band information. These schemes still suffer from prolonged recovery times and aggregated power consumption levels. Along these lines, this work proposes a fast beam restoration scheme based on deep learning in SA mmWave networks. Once the primary beam is blocked, it predicts alternative beam directions in the next time frame without any reliance on out-of-band information. The scheme adopts long short-term memory (LSTM) due to the robust memory structure, which uses past best beam observations. The scheme achieves near-instantaneous recovery times, i.e., maintaining communications sessions without resetting beam scanning procedures.
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Begishev, Vyacheslav, Edward Sopin, Dmitri Moltchanov, Andrey Samuylov, Yuliya Gaidamaka e Konstantin Samouylov. "Performance evaluation of bandwidth reservation for mmWave in 5G NR systems". Information and Control Systems, n. 5 (17 ottobre 2019): 51–63. http://dx.doi.org/10.31799/1684-8853-2019-5-51-63.
Testo completoAbstract (sommario):
Introduction: In 3GPP New Radio (NR) systems, frequent radio propagation path blockages can lead to the disconnection of ongoingsessions already accepted into the system, reducing the quality of service in the network. Controlling access to system resource byprioritizing for the ongoing sessions can increase the session continuity. In this paper, we propose resource allocation with a reservationmechanism. Purpose: Development of a mathematical model for analyzing the effect of this mechanism on other system performanceindicators – dropping probabilities for new and ongoing sessions and system utilization. The model takes into account the key featuresof the 3GPP NR technology, including the height of the interacting objects, the spatial distribution and mobility of the blockers, as wellas the line-of-sight propagation properties between the transceivers for mmWave NR technology. Results: We analyzed the reservationmechanism with the help of a developed model in the form of a resource queueing system with signals, where the base station bandwidthcorresponds to the resource, and the signals model a change in the line-of-sight conditions between the receiving and transmittingdevices. Creating a priority for ongoing sessions whose service has not yet been completed provides a considerable flexibility forbalancing the session continuity and dropping of a new session, with a slight decrease in the efficiency of the radio resource utility. Withthe developed model, we showed that reserving even a small bandwidth (less than 10% of the total resources) to maintain the ongoingsessions has a positive effect on their continuity, as it increases the probability of their successful completion. Practical relevance:
The proposed mechanism works more efficiently in overload conditions and with sessions which have a high data transfer raterequirements. This increases the demand for the proposed mechanism in 5G NR communication systems.
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Shafik, Wasswa, S. Motjaba Matinkhah, Solagbade Saheed Afolabi e Mamman Nur Sanda. "A 3-dimensional fast machine learning algorithm for mobile unmanned aerial vehicle base stations". International Journal of Advances in Applied Sciences 10, n. 1 (1 marzo 2021): 28. http://dx.doi.org/10.11591/ijaas.v10.i1.pp28-38.
Testo completoAbstract (sommario):
<p>The 5G technology is predicted to achieve the unoptimized millimeter Wave (mmWave) of 30-300 GHz bands. This unoptimized band because of the loss of mm-Wave bands, like path attenuation and propagation losses. Nonetheless, because of: (i) directional transmission paving way for beamforming to recompense for the path attenuation, and (ii) sophisticated placement concreteness of the base stations (BS) is the best alternative for array wireless communications in mmWave bands (that is to say 100-150 m). The advance in technology and innovation of unmanned aerial vehicles (UAVs) necessitates many opportunities and uncertainties. UAVs are agile and can fly all complexities if the terrains making ground robots unsuitable. The UAV may be managed either independently through aboard computers or distant controlled of a flight attendant on pulverized wireless communication links in our case 5G. Although a fast algorithm solved the problematic aspect of beam selection for 2-dimensional scenarios. This paper presents 3-dimensional scenarios for UAV. We modeled beam selection with environmental responsiveness in millimeter Wave UAV to accomplish close optimum assessments on the regular period through learning from the available situation.</p>