Yoan Shin

Spectral efficiency (SE) and energy efficiency (EE) are crucial for next-generation wireless Internet of things networks. Device-to-device (D2D) communications and sparse code multiple access (SCMA) are promising solutions to meet the high quality of service. This requires a proper interference management for an ultra-dense user system. Considering...

Multi-layered communication networks including satellites and unmanned aerial vehicles (UAVs) with remote sensing capability are expected to be an essential part of next-generation wireless communication systems. It has been reported that deep reinforcement learning algorithm brings performance improvement in various practical wireless communicatio...

In this study, we present an infrastructure-independent multi-floor indoor localization scheme that uses a deep learning (DL)-based floor detection method and a particle filter with clustering. To implement localization with limited measurement data, we incorporate the user’s vertical motion information to initialize and optimize the system. This m...

The Korean Institute of Communications and Information Sciences (KICS), which is the largest information and communication technology institute in Korea, has been active in working towards development and standardization of mobile communication technology. In response to the need to meet upcoming 6G technical challenges in innovative applications s...

Having recently become an important research topic, indoor tracking in a multi-floor building delivers comprehensive and efficient location-based services. In this paper, we present a deep learning (DL)-based indoor multi-floor tracking scheme, that is independent of infrastructure and only uses the smartphone as a terminal device to measure and an...

Inter-satellite links (ISLs) play an important role in the global navigation satellite system (GNSS), which is known as one of the key technologies for the next generation of navigation satellite systems. Deep reinforcement learning algorithms have achieved significant improvement over various wireless communications systems. However, it has been r...

Pedestrian dead reckoning (PDR), a sensor-based localization method using a smartphone, combines multi-sensor data from an inertial measurement unit (IMU) generated by the movement of pedestrians and calculates the amount of movement change from a previous location using fusion of sensor data. In this study, we propose a method to improve the effic...

With the rapid development of location-based services (LBSs), efficient and mobile-friendly localization algorithms should be designed for users to deliver a reliable LBS. In this paper, we present an algorithm with the corresponding smartphone app that enables users to calculate their locations based on representative infrastructures, such as near...

In this paper, a deep learning-based successive interference cancellation (SIC) scheme for use in nonorthogonal multiple access (NOMA) communication systems is investigated. NOMA has become a notable technique in the field of mobile wireless communication because of its capacity to overcome orthogonality, unlike a conventional orthogonal frequency...

In this letter, to improve data rate over wireless communication channels, we propose a deep Q network (DQN)-based adaptive modulation scheme by using Markov decision process (MDP) model. The proposed algorithm makes the reinforcement learning agent to select rate region boundaries as the states, which divide signal-to-noise ratio (SNR) range into...

Recently, in order to satisfy the requirements of commercial communication systems and military communication systems, automatic modulation classification (AMC) schemes have been considered. As a result, various artificial intelligence algorithms such as a deep neural network (DNN), a convolutional neural network (CNN), and a recurrent neural netwo...

Since chirp spread spectrum (CSS) system has robustness to reduce multipath fading effect and to extend spectrum bandwidth with low energy consumption, the CSS system has attracted much attention not only for radio detection and ranging systems but also for commercial wireless communication systems. In the spread-spectrum systems, low probability o...

This paper considers device-to-device (D2D) communications assisted by simultaneous wireless information and power transfer underlaying a cellular multiple-input single-output system. In such a scenario, D2Ds are enabled to harvest the energy from the base station (BS) in the downlink (DL) transmission, and then D2Ds use the harvested energy for da...

In recent research on 3D underwater wireless sensor network (UWSN), magnetic induction communication is a promising candidate, thanks to several unique features, such as small transmission delay, constant channel behavior, and adequate long communication range. However, designing a routing protocol that prolongs the network lifetime and reduces the...

A conventional relaying system is based on an orthogonal two-phase transmission protocol where time slots for the source (the first phase) and relays (the second phase) are exclusively allocated to avoid interference. For this reason, the conventional relaying schemes suffer from the reduction in spectral efficiency. In order to overcome this drawb...

Device-to-device (D2D) communication has been a potential solution to improve spectral efficiency of cellular systems due to frequency resource sharing. This paper considers D2D communications underlaying an uplink cellular system enabling sparse code multiple access (SCMA) technology, where the base station (BS) can decode the signals of cellular...

(D2D) communication has been a potential solution to improve spectral efficiency of cellular systems due to frequency resource sharing. This paper considers D2D communications underlaying an uplink cellular system enabling sparse code multiple access (SCMA) technology, where the base station (BS) can decode the signals of cellular users without mut...

This paper considers device-to-device (D2D) communications underlaying an uplink cellular network that adopts sparse code multiple access technology. We aim to maximize the spectral efficiency for D2D links in a transmission block via a joint power and resource allocation subject to the quality-of-service requirements for both cellular user equipme...

In this paper, we investigate a phase cancellation problem that occurs in tag-to-tag communication systems. These are systems wherein several tags communicate with each other by backscattering an external constant wave signal. A transmitting tag modulates baseband information onto the reflected signal using backscatter modulation. At the receiving...

A magnetic anomaly detection (MAD) scheme detects magnetic changes generated from the ferromagnetic target in the geomagnetic field. The three-axis magnetic vector sensor is considered as a technique to extend the detection range for the MAD scheme. However, in the conventional MAD scheme, the scheme detects only the magnitude signal calculated fro...

In this letter, we study a scenario based on decoupled RF energy harvesting networks (DRF-EHNs) that separate energy sources from information sources to overcome the doubly near-far problem and improve harvesting efficiency. We propose an algorithm to maximize energy efficiency (EE) while satisfying constraints on the maximum transmit power of the...

In this paper, we study an interference avoidance scenario in the presence of a smart interferer which can rapidly observe the transmit power of a backscatter wireless sensor network (WSN) and effectively interrupt backscatter signals. We consider a power control with a sub-channel allocation to avoid interference attacks and a time-switching ratio...

In this paper, we study an interference avoidance scenario in the presence of a smart interferer which can rapidly observe the transmit power of a backscatter wireless sensor network (WSN) and effectively interrupt backscatter signals. We consider a power control with a subchannel allocation to avoid interference attacks and a time-switching ratio...

This paper proposes an approach toward solving an issue pertaining to measuring compressible data in large-scale energy-harvesting wireless sensor networks with channel fading. We consider a scenario in which N sensors observe hidden phenomenon values, transmit their observations using amplify-and-forward protocol over fading channels to a fusion c...

The aim of this letter is to guarantee the ability of low probability of intercept (LPI) and anti-jamming (AJ) by maximizing the energy efficiency (EE) to improve wireless communication survivability and sustain wireless communication in jamming environments. We studied a scenario based on one transceiver pair with a partial-band noise jammer in a...

The optimum transmission strategy for maximizing energy efficiency (EE) of a multi-user massive multiple-input multiple-output (MIMO) system in radio frequency energy harvesting networks is investigated. We focus on dynamic time-switching (TS) antennas, to avoid the practical problems of power-splitting antennas, such as complex architectures, powe...

Magnetic induction (MI) based communication is one of the near-field communication techniques, which makes use of induced magnetic fields. In order to develop the MI based underwater communication networks, we evaluate and compare the loss performance between direct-MI and MI-waveguide in underwater environment.

Traffic patterns associated with different primary user (PU) channels may provide different spectral access and energy harvesting opportunities in wireless-powered cognitive radio networks (WP-CRNs). Considering this, we propose trafficspecific optimal spectrum sensing policy such that the expected transmission rate of secondary user (SU) is maximi...

In this paper, we propose a non-cooperative line-of-sight (LOS)/non-LOS channel identification algorithm with single node channel measurements based on time-of-arrival statistics. In order to improve the accuracy of channel identification, we adopt a recalibration interval in terms of measured distance to the proposed algorithm. Experimental result...

A chirp spread spectrum (CSS) system uses a chirp signal which changes the instantaneous frequency according to time for spreading a transmission bandwidth. In the CSS system, the transmission performance can be simply improved by increasing the time-bandwidth product which is known as the processing gain. However, increasing the transmission bandw...

In order to guarantee the multiuser transmission performance of a chirp spread spectrum system, the cross-correlation coefficient (CCC) among multiple users should be carefully considered. In this paper, we propose a chirp rate allocation scheme for reducing the multiple access interference based on the cross-correlation coefficient. The simulation...

In order to improve the transmission performance of a chirp signal-based chirp spread spectrum system, the cross-correlation coefficient (CCC) should be carefully considered. In this paper, we derive the CCC for analyzing the transmission performance and propose the optimal chirp rate based on the analysis. The simulation results verify the mathema...

As long term evolution (LTE) is the most widely deployed broadband communication technology so far, efforts are being made to develop LTE-based mission critical public safety (PS) communication systems. In this paper, we propose a device-to-device (D2D) discovery-based radio resource acquisition scheme to support the LTE D2D communication to PS sys...

In this paper, we consider the secondary users (SUs) who are capable of harvesting energy from ambient radio frequency (RF) signals and are allowed to sequentially sense up to 2 different channels to find out idle channels not occupied by the primary users (PUs). The EH SUs are permitted to transmit data packets only if both idle channels and suffi...

D2D (Device-to-Device) communication is one of the promising technologies in the LTE (Long Term Evolution)-Advanced communication network. From system perspective, this technology can increase frequency efficiency of the whole macro cell. From user perspective, however, a D2D pair which shares the same frequency resource of CUE (Cellular User Equip...

From a system perspective, cost effectiveness and high-precision location information are important in wireless sensor networks (WSNs). Since a weighted centroid localization (WCL) algorithm can reduce hardware installation cost and guarantee localization accuracy, this algorithm is considered as one of the promising localization algorithms for WSN...

A Markovian battery model for energy harvesting (EH) secondary users (SUs) is proposed to derive the probability of packet loss due to sensing inaccuracy and energy outage in the EH cognitive radio network (CRN). With the proposed analysis, the packet loss probability can easily be predicted and utilized to optimize the transmission policy (i.e., o...

A Markovian battery model is proposed to provide the variation of energy states for energy harvesting (EH) secondary users (SUs) in the EH cognitive radio networks (CRN). Based on the proposed battery model, we derive the packet loss probability in the EH SUs due to sensing inaccuracy and energy outage. With the proposed analysis, the packet loss p...

In this study, multicell multiuser multiple-input multiple-output systems are considered with very large number of antennas at base station. We consider a physical channel model comprised finite number of angle of arrivals, and propose a channel estimation scheme based on the eigenvalue decomposition of the covariance matrix of the received signal...

In order to improve the performance of a chirp based transmission scheme, the cross-coherence property should be carefully considered. In this paper, we propose two pairs of combinations using multiple linear chirp (MLC) which can reduce the cross-coherence for improving IEEE 802.15.4a chirp spread spectrum systems. The simulation results show that...

This paper deals with an experimental technique for monitoring machining conditions by analyzing cuttingforce vibration measured at a milling machine. This technique is based on the relationship of the cutting-force vibrations with the feed rate and cutting depth as reported earlier. The measurement system consists of dynamic force transducers and...

Underlay device-to-device (D2D) communication in cellular networks has been considered as a promising technique that can improve the spectral efficiency of cellular systems and meet the growing demand for wireless local services. In underlay D2D, it is of primary importance to manage the mutual interference between cellular links and D2D links thro...

In this paper, we considered the scenario that one cellular link and muti-D2D links share the same frequency resource which can improve the spectrum efficiency during uplink communication in LTE (Long Term Evolution)-Advanced network. In order to reduce the interference caused to the D2D users, we set DME (Discovery and Management Entity) which can...

Device-to-device (D2D) communications have emerged as a promising solution that can enable new wireless local services and can enhance the performance of wireless services in cellular networks. However, D2D links in a cellular network are difficult to establish because of mutual interference between cellular and D2D transmissions. Hence, it is of p...

D2D (Device-to-Device) communication is one of the promising technologies in the LTE (Long-Term Evolution)-Advanced communication network From a system perspective, this technology can increase frequency efficiency of the whole macro cell. From the user perspective, a D2D pair which shares the same frequency resource of CUE (Cellular User Equipment...

In this paper, we consider massive multiple-input multiple-output (MIMO) multicell systems with very large antenna arrays at base station (BS). We propose an eigenvalue decomposition (EVD) approach to evaluate the covariance matrix of the received vector at the BS, and focus on a physical channel model where the angular domain is partitioned into a...

Floor number determination has attracted considerable attention because many applications require accurate floor number information for providing better localization services in multistory buildings. This paper describes a Wi-Fi-based, low-complexity floor number determination method for multistory buildings. In our scheme, with the exception of fl...

In this paper, we propose an indoor visible light positioning system which is based on time difference of arrival (TDOA). Compared to current TDOA which uses square wave for pilot signal, our system uses sinusoidal wave for pilot signal. Our proposed system is simulated in the room measuring 5×5×3m3. In the simulations, we consider the effects shot...

The lack of wireless spectrum resource is one of the main factors constraining the further development of wireless communication, and this has been receiving increasing research attention. Cognitive radio (CR) has been demonstrated as a good solution to improve resource efficiency. Moreover, orthogonal frequency division multiplexing (OFDM) technol...

In cognitive radios, SUs (Secondary Users) coexist with PUs (Primary Users). The SUs detect those bands not used by the PUs through spectrum sensing, and transmit signals only within the limit not to interfere with the PUs. If we merely use the spectrum sensing information only in a cell with multiple PUs and SUs, the number of subcarriers that can...

This paper proposes improved detection schemes for concealed micro-electronic devices using clustering and classification of radio frequency harmonics in order to protect intellectual property rights. In general, if a radio wave with a specific fundamental frequency is propagated from the transmitter of a classifier to a concealed object, the secon...

D2D (Device-to-Device) communication on an underlying cellular infrastructure which exploits the same spectrum has several advantages such as increased resource utilization and improved cellular coverage. However, D2D communication system needs to cope with ICI (Inter-Cell Interference) and interference between cellular and D2D links. As a result,...

In this paper, we propose an inter-cell interference management scheme using a multi-cell SRN (Shared Relay Node) in order to avoid inter-cell interference and to increase the cell throughput in 3GPP LTE (3rd Generation Partnership Project Long Term Evolution)-Advanced networks. Recently, the CoMP (Coordinated Multi-Point transmission/reception) sc...

3GPP LTE-Advanced (Third Generation Partnership Project Long Term Evolution-Advanced) as a next generation mobile communication standard introduced small base stations such as femto cells or pico cells, and D2D (Device-to-Device) communications between mobiles in the proximity in order to satisfy the needs of rapidly growing wireless data traffic....

As progress is made towards attaining Millennium Development Goal 4, further reductions in paediatric mortality will only be achieved by concentrating on the burden of non-communicable or neglected diseases. The literature relating to paediatric cardiac disease in sub-Saharan Africa is sparse. There are no published descriptions of paediatric cardi...

Device-to-Device (D2D) communication will become an important technology in future wireless networks with increasing demand for local communication services. In particular, enabling D2D links in a cellular network presents a challenge in radio resource management due to the interference between cellular and D2D terminals. Many research works have c...

As the long term evolution (LTE) standard comes to an end, 3rd Generation Partnership Project is discussing further evolution of the LTE to meet the international mobile telecommunications advanced requirements, which is referred to as LTE-Advanced (LTE release 10 and beyond). This article first presents the network infrastructure of the LTE-Advanc...

In an intelligent automated manufacturing environment, an administrator may use M2M (Machine-to-Machine) communication to recognize machine movement and the environment, as well as to respond to any potential dangers. However, commonly used wireless protocols for this purpose such WLAN (Wireless Local Area Network), ZigBee, and Bluetooth use the sa...

We present an effective scheme for preventing eavesdropping in wireless communication systems. In the proposed scheme, the modulation scheme is designed to change based on an expanded signal constellation, in such a way that the eavesdropper cannot be aware of the change. As compared to previously proposed schemes that rely on specific relay nodes,...