• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1826-1829
• /
• 2005

Recent advancement in wireless communications and electronics has enabled the development of low power sensor network. Wireless sensor network are often used in remote monitoring control applications, health care, security and environmental monitoring. Wireless sensor networks are an emerging technology consisting of small, low-power, and low-cost devices that integrate limited computation, sensing, and radio communication capabilities. Sensor network platform for health care has been designed, fabricated and tested. This system consists of an embedded micro-controller, Radio Frequency (RF) transceiver, power management, I/O expansion, and serial communication (RS-232). The hardware platform uses Atmel ATmega128L 8-bit ultra low power RISC processor with 128KB flash memory as the program memory and 4KB SRAM as the data memory. The radio transceiver (Chipcon CC1000) operates in the ISM band at 433MHz or 916MHz with a maximum data rate of 76.8kbps. Also, the indoor radio range is approximately 20-30m. When many sensors have to communicate with the controller, standard communication interfaces such as Serial Peripheral Interface (SPI) or Integrated Circuit ($I^{2}C$) allow sharing a single communication bus. With its low power, the smallest and low cost design, the wireless sensor network system and wireless sensing electronics to collect health-related information of human vitality and main physiological parameters (ECG, Temperature, Perspiration, Blood Pressure and some more vitality parameters, etc.)

• Journal of Communications and Networks
• /
• v.14 no.6
• /
• pp.629-639
• /
• 2012

A challenge faced by smart grid systems is providing highly reliable transmissions to better serve different types of electrical applications and improve the energy efficiency of the system. Although wireless networking technologies can provide high-speed and cost-effective solutions, their performance may be impaired by various factors that affect the reliability of smart grid networks. Here, we first suggest the use of IEEE 802.11s-based wireless LAN mesh networks as high-speed wireless backbone networks for smart grid infrastructure to provide high scalability and flexibility while ensuring low installation and management costs. Thereafter, we analyze some vital problems of the IEEE 802.11s default routing protocol (named hybrid wireless mesh protocol; HWMP) from the perspective of transfer reliability, and propose appropriate solutions with a new routing method called HWMP-reliability enhancement to improve the routing reliability of 802.11s-based smart grid mesh networking. A simulation study using ns-3 was conducted to demonstrate the superiority of the proposed schemes.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2006.07a
• /
• pp.753-753
• /
• 2006

• IEMEK Journal of Embedded Systems and Applications
• /
• v.7 no.2
• /
• pp.95-101
• /
• 2012

In order to supply emotion service depending on user's emotional change in a mobile environment, various researches have been carried. This paper discusses a protocol for wireless charging and an embedded platform of the mobile emotional sensing device which supports that. Wireless charging process relieves user's vexatious task to charge the emotional sensing device. To support wireless charging, there are one basestation and several mobile devices. Basestation coordinates and controls the devices over wireless communication, as well as supplies energy. For 1:N communication we defines the network whose superframe is classified into four categories: a network join superframe, a charging request superframe, a charging superframe and an inactive superframe. Physical layer provides how to supply energy to the devices and communicate physically. Mobile device is equipped with energy charged circuits, which correspond with the defined energy supplying method, as well as bidirectional communication circuits. Mobile device monitors and analyzes its own battery status, and is able to send a request packet to basestation. Therefore, it can be charged before its battery is exhausted without user's perception.

• ETRI Journal
• /
• v.40 no.1
• /
• pp.89-100
• /
• 2018

Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use-case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof-of-concept wireless backhaul solution developed within the EU-KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over-the-air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.3
• /
• pp.911-923
• /
• 2014

Ad hoc cognitive radio wireless sensor networks allow secondary wireless sensor nodes to recognize spectrum opportunities and transmit data. Most existing protocols proposed for ad hoc cognitive radio wireless sensor networks require a dedicated common control channel. Allocating one channel just for control packet exchange is a waste of resources for channel-constrained networks. There are very few protocols that do not rely on a common control channel and that exchange channel-negotiation control packets during a pre-allocated time on the data channels. This, however, can require a substantial amount of time to access the channel when an incumbent is present on the channel, where the nodes are intended to negotiate for the data channel. This study examined channel access delay on cognitive radio wireless sensor networks that have no dedicated common control channel.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.11 no.1
• /
• pp.89-94
• /
• 2018

This paper investigated the design method of the smart sensor for implementing IoT (Internet of Things) service. The power supply of sensor consistently acquisting data is based on the energy harvesting technology and designed with piezoelectric transducer not affected by surrounding circumstances. The wireless communication interface for the transmission of data is designed with BLE (Bluetooth Low Energy). BLE is highly adequate wireless communication technology for low power consumption and short distance wireless communication. The main application of BLE is beacon whose usage range is extended from O2O (Online to Offline) service, navigator based on indoor positioning technology, and anti-theft/lost child prevention service to mobile game. This paper studied the method to extend wireless coverage for complementing the short wireless transmission distance of BLE. The wireless sensor network based on CATV network is proposed for the easy construction of BLE sensor network and extended wireless coverage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.7
• /
• pp.599-611
• /
• 2016

This paper proposes a cognitive engine platform that enables dynamic spectrum access(DSA) based on a spectrum sharing system for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary wireless spectrum to ensure that multiple wireless networks for different weapon systems co-exist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper examined policy development and research activities engaged by the U.S. and European countries on wireless spectrum sharing to secure more spectrum. It also introduces the current status of cognitive engine development, which is the core technology of tactical wireless communication for DSA. In addition, based on the investigation performed into the latest trends, we propose a platform structure for a cognitive engine based on a spectrum sharing method where more frequencies can be added for tactical radio communication, so that DSA can be realized, and wireless networks of different weapon systems can co-exist.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.4
• /
• pp.85-98
• /
• 2003

Computational power of IC chip is improved day after day producing IC chips holding co-processor continuously. Also a lot of wireless terminals which IC chip embedded in are produced in order to provide simple and various services in the wireless terminal market. However it is difficult to apply the key distribution protocol under wired communication environment to wireless communication environment. Because the computational power of co-processor embedded in IC chip under wireless communication environment is less than that under wired communication environment. In this paper, we propose the hey distribution protocol appropriate for wireless communication environment which diminishes the computational burden of server and client by using co-processor that performs cryptographic operations and makes up for the restrictive computational power of terminal. And our proposal is satisfied with the security requirements that are not provided in existing key distribution protocol.

• Journal of the Semiconductor & Display Technology
• /
• v.18 no.2
• /
• pp.32-37
• /
• 2019

In this paper, we have designed a solar photovoltaic system to attach solar photovoltaic modules to each module and develop the best efficiency in each module. The efficiency of the designed solar panel optimizer was more than 99.27% and MPPT efficiency of 99.66%. In addition, the monitoring of power generation and abnormal operation phenomenon in each optimum period and tracking for failure location of specific photovoltaic module have improved the utilization rate of photovoltaic power generation. Wired and wireless communication methods has been proposed to monitor the power generation and operation status of the solar panel optimizer. For this purpose, the RS485 communication was used for wire communication and Zigbee communication was used for wireless communication to monitor the status of each module in real time. It is shown that communication redundancy can be achieved through the proposed method, and the possibility of commercialization is suggested.