• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.129-131
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• 1993

A transcutaneoos information transmission system using transmitted infrared light for an implantable total artificial heart(TAH) an developed and the performance of the system was tested. In an in vitro test, transmittance of the developed system was measured through various thicknesses of pig shins. In an in vivo test, a loopback test using a personal computer was performed to determine the error rate and an experiment using a mock system was taken. In this experiment, within acceptable lateral and vertical displacements, the error rate of at least 3.8E-6 was guaranteed. Monitoring signals from the internal controller(Intel 87C196) of the mock system were successfully transmitted to the external controller(IBM PC) and the operating commands from the external controller were successfully conducted by the mock system. Communication was done in half duplex mode according to RS-232 protocol at the speed of 4800 bps.

• ETRI Journal
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• v.34 no.2
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• pp.216-225
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• 2012

This paper presents a transceiver module for human body communications whereby a spread signal with a group of 64 Walsh codes is directly transferred through a human body at a chip rate of 32 Mcps. Frequency selective digital transmission moves the signal spectrum over 5 MHz without continuous frequency modulation and increases the immunity to induced interference by the processing gain. A simple receiver structure with no additional analog circuitry for the transmitter has been developed and has a sensitivity of 250 ${\mu}V_{pp}$. The high sensitivity of the receiver makes it possible to communicate between mobile devices using a human body as the transmission medium. It enables half-duplex communication of 2 Mbps within an operating range of up to 170 cm between the ultra-mobile PCs held between fingertips of each hand with a packet error rate of lower than $10^{-6}$. The transceiver module consumes 59 mA with a 3.3 V power supply.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.282-289
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• 2010

A simplified, practical vector network analyzer (VNA) that uses mature radio-over-fiber technology has been designed and demonstrated. The measurement concept allows the full S-parameters of a microwave device (or antenna) to be obtained while minimizing the detrimental effects of electrical cables, which are replaced with a photonic link. A variety of high-frequency light modulation schemes with frequency sweeping capabilities are presented to realize a one-path (single, forward), frequency-multiplied optical link for VNA applications. Using the photonic one-path link, full two-port S-parameters have been extracted based on five-term error modeling, which has half the error terms compared with the standard duplex configuration. The S-parameters of a microwave filter and antenna measured using frequency-multiplied optical links are found to be in good agreement with those obtained using a conventional VNA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4878-4883
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• 2015

The IP Multimedia Subsystem(IMS) is a framework that provides access to the content of Internet and Telecom services anytime and anywhere with guaranteed Quality of Service(QoS) and manageability by separating control functions from bearer and services. The Service Delivery Platform(SDP) provides common interfaces and protocols to deploy existing or new services in an efficient way. Therefore SDP over IMS plays a role of bridge between established network and new IMS network by simplifying the interaction among application services. In order to enrich the multimedia network communication, we try to deploy the Push-to-talk over Cellular(PoC) service which is considered as the outstanding and distinguished half-duplex Voice over IP(VoIP) application service among deployable candidate services over mobile network. In this paper we investigate the advantages of PoC service and PoC architecture firstly, and then focus on the its practical implementation for the prototype to validate the feasibility of its deployment and realization.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.511-519
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• 2017

This Paper introduces the design and communication method between PLC (Programmable Logic Controller) and Arduino based on MODBUS Protocol. MODBUS connection can be established in a new or existing system very easily, therefore we used this protocol in our proposed system. In the field of automatic devices, multi-function serial port such as RS232, RS422, RS485, and so on creates a great convenience to the developer. This proposed system used RS485 as a key mediator for data exchanging on a connected network. We also believe that it will reduce the development cost in various automated industry because this system can be reused or can be implemented any such PLC installed machines. RS485 is used as a communication interface between PLC (as a slave) and Arduino (as a master), through which a reliable network is created for safe and fast communication. Furthermore, RS485 allows multiple devices(up to 32) to communicate at half duplex on a single pair of wires and provides a long connectivity area (up to 1200 meters) as compare to other device, which makes it a user-friendly for various devices in the automated industry. Moreover, Arduino can play as a mediator by connecting third party device and setup a communication network with PLC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.756-765
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• 2004

Using single carrier frequency RFID system in one-to-multiple wireless communications, might be generated data loss because of data collisions. Conventional Anti-collision method prevent data loss from data collisions which are binary tree method and ALOHA. However, those two preventive measures also have week points which are strongly dependent on the time and space when passing through the recognition area. This paper suggests the full-length instruction code method which fits in to half-duplex method, prevents data collision effectively by calculating the non-transmitting time of multiple tags considering approaching time to the recognition area. After full-length instruction code method test using 13.56MHz bandwidth RFID system shows that full-length instruction code method could make better result than any other methods. Moreover, the record shows O(n) result after analyzing O-notation of conventional time-domain procedure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.593-600
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• 2014

OFDMA systems solves frequency selective fading problem and provides improved performance by optimal allocation of subcarriers and transmit power. Two-way relay systems provide improved spectral efficiency compared to that of the conventional half-duplex relay using bidirectional communications. In legacy OFDMA system such as WiBro, two-way DF relay utilization causes pilot re-assignment and impossibility of channel estimation and decoding at relay nodes by self-interference. In this paper, resource allocation schemes for legacy OFDMA systems with two-way DF relay are proposed. The proposed schemes allocate subcarriers considering destinations nodes which are connected to relay nodes as individual nodes which are directly connected to a base station. Subsequently, the proposed schemes compensate bandwidth loss due to orthogonal allocations by overlapped allocating unused subcarriers at other noes. Numerical simulations show that the proposed resource allocation schemes provide improved performance compared with orthogonal allocation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2021-2026
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• 2007

In the parer, we design a non-coherent UWB system by adopting the architecture of a simplified asynchronous transmission and the edge-triggered pulse transmission, which makes e system performance independent of the share of the transmitted waveform, robust to multipath channels. The designed non-coherent UWB transceiver architecture has an advantage of the simple realization since any mixer, high-speed correlator, and high-sampling A/D converter are not necessary at the cost of performance degradation of about 3dB. Further, the designed non-coherent UWB transceiver is actually implemented with the wireless CANVAS prototype testbed in short range indoor application environments such as a lecture room. The implemented prototype testbed is proven to offer the data rate of 115kbps on the conditions of Peer-to-Peer(P-to-P) in the indoor channel within the range of about 10m.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.660-665
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• 2018

Research into underwater wireless networks that enable the monitoring and controlling of the ocean environments has been continuing for disaster prevention and military proposes, as well as for the exploitation of ocean resources throughout the world. A research group led by Hoseo university has been studying a distributed underwater monitoring and controlling network. In this study, we developed an interpolator for acoustic communication between an underwater base station controller and underwater base station, which is included in this network. The underwater acoustic communication provided by this network defines four links whose sampling rates are different. Low power consumption is one of the most important requirements. Therefore, we adopted CIC interpolators, which are known to act as filters with a low power consumption, and some CIC interpolators with an appropriate changing rate were selected depending on the link. However, these interpolators have a large passband drop and wide transition region. To solve these problems, we added a compensator and half-band filter. After verifying the algorithm by using Matlab, we designed and verified it with Verilog-HDL in a ModelSim environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2249-2260
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• 2017

IMO (International Maritime Organization) has been providing GMDSS (Global Maritime Distress and Safety System) and mandating to install distress and safety systems according to SOLAS. Digital-HF(High-Frequency) coast station communication system maintains interoperability between ship and coast station and digital data exchange in maritime mobile service by digitizing existing analog base voice communication. In this paper, we analyze ITU-R M. 1798-1 established by ITU for digital HF communications and propose Advanced annex2 and new Annex 5 to improve the problems of the existing Annex 2 and Annex 4. The proposed OFDM protocol basically adopts ARQ (Automatic Retransmission Request) which retransmits when an error occurs in a half-duplex manner between an information transmitting side (ISS) and an information receiving side (IRS) and we propose a digital HF communication system and its operational concept which is more reliable and superior than the existing ITU-R M. 1798 by implementing technical development on implementation and performance improvement.