Minseok Kim

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Verified

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• Doctor of Engineering
• Professor (Associate) at Niigata University

The THz band (0.1-10 THz) is emerging as a crucial enabler for sixth-generation (6G) mobile communication systems, overcoming the limitations of current technologies and unlocking new opportunities for low-latency and ultra-high-speed communications by utilizing several tens of GHz transmission bandwidths. However, extremely high spreading losses a...

To design a reliable communication system leveraging millimeter-wave (mm-wave) technology-gaining popularity for its capacity to deliver multi-gigabit-per-second data rates-it is essential to consider the site-specific nature of mm-wave propagation. Conventional site-general stochastic channel models often fail to reproduce channel responses in spe...

In this paper, we introduce our millimeter-wave (mmWave) radio channel measurement for integrated sensing and communication (ISAC) scenarios with distributed links at dual bands in an indoor cavity; we also characterize the channel in delay and azimuth-angular domains for the scenarios with the presence of 1 person with varying locations and facing...

In this paper, comprehensive double-directional channel measurements at 300 GHz in various usage scenarios in corridor environments, such as Access, Device-to-device (D2D) , and Backhaul over 40 different receiver (Rx) positions using an in-house developed channel sounder, are presented. The measurement results are analyzed and validated by ray...

This letter tries to address the fundamental questions on the feasibility of multipath communication and achievable capacity for line-of-sight (LoS), obstructed-line-of-sight (OLoS), and non-line-of-sight (NLoS) scenarios in an outdoor setting for futuristic communication networks. In this context, a relevant measurement campaign at 300 GHz is cond...

A site-specific radio channel representation considers the surroundings of the communication system through the environment geometry, such as buildings, vegetation, and mobile objects including their material and surface properties. In this article, we focus on communication technologies for 5G and beyond that are increasingly able to exploit the s...

Currently, millimeter-wave (mm-wave) based wireless communications in the 30 to 300 GHz frequency band are attracting new attention because the existing frequency band below 6 GHz is very congested. In order to design and assess mm-wave systems, it is essential to characterize its propagation channel considering the spatial consistency (SC) for non...

This paper presents a novel localization technique—Multipath-radio tomographic imaging (RTI)—based on millimeterwave (mm-wave) radio systems, such as 5G mobile and WiGig LAN systems. Because of their high delay and angle resolutions, mm-wave radio systems can realize highly accurate device-free localization (DFL) for smart home/smart building appli...

This paper presents a novel localization technique—Multipath-radio tomographic imaging (RTI)—based on millimeter-wave (mm-wave) radio systems, such as 5G mobile and WiGig LAN systems. Because of their high delay and angle resolutions, mm-wave radio systems can realize highly accurate device-free localization (DFL) for smart home/smart building appl...

To design a reliable communication system utilizing millimeter-wave (mm-wave) technology, which is gaining popularity due to its ability to deliver multi-gigabit-per-second data rate, it's essential to consider the site-specific nature of the mm-wave propagation. Conventional site-general stochastic channel models are often unsatisfactory for accur...

A site-specific radio channel representation (SSCR) takes the surroundings of the communication system into account by considering the environment geometry, including buildings, vegetation, and mobile objects with their material and surface properties. We present methods for an SSCR that is spatially consistent, such that mobile transmitter and rec...

In sixth-generation (6G) application scenarios like industry 5.0, augmented reality (AR), autonomous transportation, and eHealth, there is a growing demand for Human Activity Recognition (HAR). Meanwhile, with the deployment of millimeter-wave (mmWave) technologies in fifth-generation (5G) cellular communications, higher-resolution sensing becomes...

In recent years, cluster-based channel models comprising clusters or groups of multipath components (MPCs) have found a lot of acceptance in the research community. However, such models are heavily clustering technique dependent where there is a primary lack of uniformity regarding distance measure or the number of initial parameters. In this work,...

Currently, millimeter-wave (mm-wave) based wireless communications in the 30 to 300 GHz frequency band are attracting new attention because the existing frequency band below 6~GHz is very congested. In order to use the mm-wave bands for designing and assessing next-generation mobile systems, it is essential to characterize its propagation channel c...

p>In this paper, a newly developed 300 GHz channel sounder is presented followed by a detailed description of test measurements and the subsequent results obtained to validate its working. An elucidation of the high-resolution double-directional channel measurement in a typical conference room scenario precedes the comparison of the results obtaine...

Currently, millimeter-wave (mm-wave) based wireless communications in the 30 to 300 GHz frequency band are attracting new attention because the existing frequency band below 6~GHz is very congested. In order to use the mm-wave bands for designing and assessing next-generation mobile systems, it is essential to characterize its propagation channel c...

p>In this paper, a newly developed 300 GHz channel sounder is presented followed by a detailed description of test measurements and the subsequent results obtained to validate its working. An elucidation of the high-resolution double-directional channel measurement in a typical conference room scenario precedes the comparison of the results obtaine...

p>This paper presents a novel localization technique—Multipath-radio tomographic imaging (RTI)—based on millimeterwave (mm-wave) radio systems, such as 5G mobile and WiGig LAN systems. Because of their high delay and angle resolutions, mm-wave radio systems can realize highly accurate device-free localization (DFL) for smart home/smart building app...

p>This paper presents a novel localization technique—Multipath-radio tomographic imaging (RTI)—based on millimeterwave (mm-wave) radio systems, such as 5G mobile and WiGig LAN systems. Because of their high delay and angle resolutions, mm-wave radio systems can realize highly accurate device-free localization (DFL) for smart home/smart building app...

In recent years, there has been a spurt of activities to explore the terahertz (THz) band comprising frequencies above 100 GHz to support high data rates and low latency applications. In this light, the current study presents an overview of a novel in-house channel sounder operating at 300 GHz followed by elaboration of a high-resolution double-dir...

As the world warms up to the idea of millimeter wave (mmWave) communication and fifth generation (5G) mobile networks, realization slowly dawns that the data rate, latency, throughput, and other performance metrics that are used to assess a new wireless communication technology will not be enough to support the demands of envisioned futuristic appl...

In this paper, a newly developed 300 GHz channel sounder is presented followed by a detailed description of test measurements and the subsequent results obtained to validate its working. An elucidation of the high-resolution double-directional channel measurement in a typical conference room scenario precedes the comparison of the results obtained...

The authors have developed the Multipath-RTI (radio tomographic imaging) technique based on millimeter-wave (mm-wave) radios such as 5G mobile and WiGig LAN systems. Mm-wave radios can realize a highly accurate device-free lo-calization (DFL) for smart home/smart building applications by utilizing the features that mm-wave radios usually have high...

In recent years, the discovery and utilization of the millimeter-wave bands for the next generation of mobile communications have raised the demand to develop more accurate wireless channel models. Due to the dynamic and high interactive nature of the millimeter waves, accurate models which takes into consideration the effects of the interacting ob...

The use of millimeter-wave (mm-wave) bands has been expanding in new wireless communication systems such as fifth-generation (5G) mobile systems and WiGig WLANs. Since mm-waves have quasi-optical propagation characteristics, it is necessary to develop a channel model that can cover site-specific characteristics of various environments. For this rea...

The use of millimeter-wave (mm-wave) bands has been expanding in new wireless communication systems such as fifth-generation (5G) mobile systems and WiGig WLANs. Since mm-waves have quasi-optical propagation characteristics, it is necessary to develop a channel model that can cover site-specific characteristics of various environments. For this rea...

This paper developed a 60-GHz millimeter-wave cluster channel model for various office environments and investigated the impact of cluster characteristics on wireless data transmission. We conducted double-directional channel measurement campaigns in a university laboratory office environment to develop the channel model using a custom-developed ch...

This paper presents a multipath component (MPC) parameter estimator that uses a double-directional (D-D) channel sounding system in WiGig millimeter-wave bands. It employs low-cost commercial-off-the-shelf (COTS) RF transceivers capable of beam steering within an azimuth angle range of ±45°; the transmit power is approximately 31 dBm, equivalent is...

Human motion classification is emerging technology which can improve healthcare system and to realize context-aware body area network (BAN). This study focused the fact that the radio channel characteristics between sensor devices and coordinator may have stronger potential for motion classification than the conventional methods using accelerometer...

Millimeter wave transmission systems offer a multi-gigabit data transmission with beamforming toward the user direction to compensate for the large propagation loss. However, the abrupt performance degradation due to human blockage is still a critical problem, thus utilizing the possible reflected paths when blockage occurs should be considered. In...

For realizing automated monitoring of the behavior and preferences of residents for smart homes/smart building applications, device-free localization techniques using radio propagation characteristics have gained interest. In such techniques an environmental information should often be known in advance. This study developed the multi-dimensional Ki...

In recent years, propagation channel characteristics have been effectively used in several applications such as motion sensing and position detection. Considerable attention has been paid to channel-sounding methods that are easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using the spatio-...

This paper reports the measurement campaign and identification results of the millimeter-wave multi-path propagation characteristics at 61.5 GHz band in a passenger vehicle environment. Four measurement scenarios were assumed, and the propagation characteristics of the dominant paths in each were identified. From the results, it can be seen that th...

Aiming at realizing sensing of the surrounding environment for smart homes/smart building applications, device-free localization techniques using radio propagation characteristics have gained interest. To realize such techniques it is often required that the accurate environmental information should be obtained in advance. In this study, the enviro...

To date various wireless systems using millimeter-wave bands have already been developed. However, the demand for more accurate channel models is still increasing. In this study, a millimeter-wave double-directional channel sounding system using commercial off-the-shelf RF transceivers is presented where an analog beamformer based electrical beam-s...

In recent years, IoT and AI technologies have been developing rapidly. To utilize these technologies in home environment, it is important to capture and visualize environmental information in a house. This study developed an indoor positioning method using multi-path radio tomography imaging (RTI) based on millimeter-wave (mm-wave) radio systems su...

In recent years, since the propagation channel characteristics have been effectively used for applications such as motion sensing, position detection, etc. A great deal of attention is attracted to channel sounding methods easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using spatio-tempor...

This paper proposed a multi-path component (MPC) parameter estimation method which is developed for a novel double-directional channel sounding system in the WiGig millimeter-wave bands, where beamforming RF transceivers realizes a fast double-directional channel acquisition by analog beamformers incorporating16-patch antenna element uniform linear...

In recent years, since the propagation channel characteristics have been effectively used for applications such as motion sensing, position detection, etc. A great deal of attention is attracted to channel sounding methods easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using spatio-tempor...

This paper proposed a multi-path component (MPC) parameter estimation method which is developed for a novel double-directional channel sounding system in the WiGig millimeter-wave bands, where beamforming RF transceivers realizes a fast double-directional channel acquisition by analog beamformers incorporating16-patch antenna element uniform linear...

Aiming at realizing sensing of the surrounding environment for smart homes/smart building applications, device-free localization techniques using radio propagation characteristics have gained interest. To realize such techniques it is often required that the accurate environmental information should be obtained in advance. In this study, the enviro...

To date various wireless systems using millimeter-wave bands have already been developed. However, the demand for more accurate channel models is still increasing. In this study, a millimeter-wave double-directional channel sounding system using commercial off-the-shelf RF transceivers is presented where an analog beamformer based electrical beam-s...

This paper reports the measurement campaign and identification results of the millimeter-wave multi-path propagation characteristics at 61.5 GHz band in a passenger vehicle environment. Four measurement scenarios were assumed, and the propagation characteristics of the dominant paths in each were identified. From the results, it can be seen that th...

In recent years, IoT and AI technologies have been developing rapidly. To utilize these technologies in home environment, it is important to capture and visualize environmental information in a house. This study developed an indoor positioning method using multi-path radio tomography imaging (RTI) based on millimeter-wave (mm-wave) radio systems su...

In recent years, since the propagation channel characteristics have been effectively used for applications such as motion sensing, position detection, etc. A great deal of attention is attracted to channel sounding methods easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using spatio-tempor...

This paper analyzes a scenario where single or multiple sensors placed on a parked car help the owner to find the car in a parking lot. It is assumed that the sensors communicate with the owner device over ultra-wide-band (UWB)and the owner device only records the received signal strength(RSS) values. Based on the RSS data, which are obtained from...

By technical progress of IoT (internet-of-things) a highly advanced automated home environment for living will be on hand in near future. Here, indoor localization and mapping will be playing an important role. Various localization/positioning techniques have been developed, but the performance of them often considerably decreases in actual multipa...

A quasi-deterministic (Q-D) channel model is a channel modeling approach that considers the millimeter-wave propagation properties and has been adopted in IEEE 802.11ay. This study conducted the measurement campaigns in a conference room environment to develop and validate the Q-D channel model for indoor access scenarios. The multi-path components...

This paper establishes the analytical model and analyzes the statistical behaviors of multimode channels in spherical vector wave (SVW) domain based on the microcellular radio channel measurement in downtown Helsinki at 5.3 GHz band. The multimode channel is the representation of radio wave propagation in the form of the SVW mode coupling between t...

The IEEE 802.11ay channel models have been developed based on the quasi-deterministic (Q-D) channel modeling that considers environment specific property of millimeter-wave (mm-wave) propagation by representing multi-path channels as superposition of deterministic (called D-ray) and random clusters (called R-ray). Based on the Q-D model, this lette...

To develop an millimeter-waves (mm-waves) channel model for in-room access scenarios, a double-directional channel measurement campaign conducted in a conference room environment is presented. In the measurements, a custom-developed channel sounder with a 12° angle and 2.5-ns delay resolutions at 58.5 GHz was used. From the measured data, the multi...

In radio channel measurements and modeling, directional scanning via highly directive antennas is the most popular method to obtain angular channel characteristics to develop and evaluate advanced wireless systems for high frequency band use. However, it is often insufficient for ray-/cluster-level characterizations because the angular resolution o...

This paper presents a real-time body motion classification system using the radio channel characteristics of a wearable body area network (BAN). We developed a custom wearable BAN radio channel measurement system by modifying an off-the-shelf ZigBee-based sensor network system, where the link quality indicator (LQI) values of the wireless links bet...

In this article, a millimeter-wave radio channel model for indoor multi-gigabit access links was presented. In order to develop a channel model, we carried out measurement campaigns in a conference room environment. By using super-resolution path parameter estimation algorithm, multi-path rays were extracted from the measurement data, and by applyi...

In this study, we propose a new radio tomographic imaging (RTI) technique, called Multipath-RTI, using millimeter-wave (mm-wave) radios such as 5G mobile and WiGig LAN systems, which will realize a highly accurate device-free human movement monitoring for smart home/smart building applications. Utilizing the features that mm-wave radios usually hav...

For seamless communication in millimeter-wave (mm-wave) transmission systems, the robustness against link blockage and user mobility should be guaranteed. Cooperative joint network design over conventional microwave bands and mm-wave bands is essential in future mm-wave WLANs (e.g., IEEE 802.11ay) and 5G cellular networks, and hence understanding t...

In millimeter wave transmission systems, line-ofsight communication offers a multi-gigabit data transmission with beamforming toward the user direction to compensate for the large propagation loss. However, the abrupt performance degradation due to human blockage is still a critical problem, and thus utilizing the possible reflected paths when bloc...

A quasi-deterministic (Q-D) channel model has been proposed as an appropriate channel modeling approach considering the millimeter-wave propagation properties. As a preliminary stage of Q-D channel modeling, this paper presented the scattering process identification and cluster analysis in a typical conference room environment. The results revealed...

Facing with the problems of declining birthrates, aging society, and shrinking population, the information communication technology (ICT) for medical healthcare applications is emerging. Recently, daily monitoring of heartbeats and breathing offers a promising solution to prevent lifestyle-related diseases, and enables early treatment of diseases....

Researchers have encountered many challenges in developing communication system in wireless body area networks (WBANs). These challenges include the dynamic characteristics of WBAN channels, limited energy resources, and strict requirements, such as high reliability and low latency. To achieve highly reliable and energy-efficient communication in t...

Human motion classification is emerging technology which can improve healthcare system and to realize context-aware body area network (BAN). This paper focused the fact that the radio channel characteristics between sensor devices and coordinator may have stronger potential for motion classification than the conventional methods using accelerometer...

To resolve the crowded radio spectrum problem observed in conventional microwave bands (below 6 GHz), new frequency bands higher than 6 GHz are being considered to facilitate the use of a much wider bandwidth for next-generation wireless systems. Various channel sounding measurements have been conducted to elucidate the radio propagation properties...

This paper presents a clustering and tracking method that exploits the geometry of the scattering points (SPs) obtained from the measurement-based ray tracer. The multipath components (MPCs) were categorized into clusters by applying the KPowerMeans (KPM) framework to those SPs. The clusters were tracked by comparing the cluster-centroid SPs of the...

In order to utilize higher frequency bands above 6 GHz, which is an important technical challenge in fifth generation mobile systems, radio propagation channel properties in a large variety of deployment scenarios should be thoroughly investigated. The authors' group has also been involved in a fundamental research project aimed at investigating mu...

In the next-generation mobile communication system, the higher frequency bands from C band to V band are expected to be utilized because it has the potential to improve network capacity drastically by the available wideband spectrum. Since the characteristics of reflected and scattered radio waves from surrounding environments in those bands are th...

This paper discusses intrinsic problems to realize low side-lobe beam forming by synthetic cylindrical array, and presents some indeterminate results. It is shown that the phase mode excitation based beamformer on the circular array is useful only if all impinging waves have the same elevation angle, but is applicable to the multi-path signals havi...