• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.4
• /
• pp.43-51
• /
• 2010

In this paper, we studied line coding technology tendency for high speed data communication at LED-ID (Identification) communication system in indoor environment. A LED-ID technology is a communication using visible ray (RGB) that come out in LED device. It is energy curtailment effect and possible in ubiquitous network service applications. The LED-ID system has the above advantages about that the communication throughout the whole room is enabled by high power lighting and lighting equipment with white colored LED which are easy to install and have good outward appearance. Therefore, the transmission by light waves is more suitable for wireless networks than by radio waves. We compared with the NRZ, AMI, 4B5B, HDB3, 8B10B line coding for efficient in error detection and serves data transmission of high speed.

• Journal of Internet Computing and Services
• /
• v.21 no.2
• /
• pp.19-26
• /
• 2020

This paper analyses the feasibility of using implantable antennas to detect and monitor tumors. We analyze this setting according to the wireless propagation loss and signal fading produced by human bodies and their environment in an indoor scenario. The study is based on the ITU-R propagation recommendations and prediction models for the planning of indoor radio communication systems and radio local area networks in the frequency range of 300 MHz to 100 GHz. We conduct primary estimations on 915 MHz and 2.4 GHz operating frequencies. The path loss presented in most short-range wireless implant devices does not take into account the human body as a channel itself, which causes additional losses to wireless designs. In this paper, we examine the propagation through the human body, including losses taken from bones, muscles, fat, and clothes, which results in a more accurate characterization and estimation of the channel. The results obtained from our simulation indicates a variation of the return loss of the spiral antenna when a tumor is located near the implant. This knowledge can be applied in medical detection, and monitoring of early tumors, by analyzing the electromagnetic field behavior of the implant. The tumor was modeled under CST Microwave Studio, using Wisconsin Diagnosis Breast Cancer Dataset. Features like the radius, texture, perimeter, area, and smoothness of the tumor are included along with their label data to determine whether the external shape has malignant or benign physiognomies. An explanation of the feasibility of the system deployment and technical recommendations to avoid interference is also described.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.11
• /
• pp.79-86
• /
• 2005

This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency $30khz\~1Mhz$ band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

• Journal of Digital Convergence
• /
• v.12 no.11
• /
• pp.273-279
• /
• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.

• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.237-240
• /
• 2000

In this paper, we design the system that support data rate of 6Mbps(BPSK), 12Mbps(QPSK), 24Mbps(16-QAM) with OFDM, and the performance of this system analyze in the indoor channel when BER is 10$\^$-3/. In this simulation, first, we analyze performance of the system with and without channel coding. As the result, the coding gain of each system is 2㏈, 1.6㏈, 2㏈ when BER is 10$\^$-3/ Second, In the case of 16-QAM/OFDM, The effect of soft decision channel decoding method improve 2㏈ than hard decision when BER is 10$\^$-3/.

• Journal of Broadcast Engineering
• /
• v.5 no.2
• /
• pp.273-280
• /
• 2000

Channel characteristics between the outdoor transmitter far away from the building and receivers inside the building are explored theoretically using ray tracing technique. In this paper, 29 receivers are located on the single floor of the building to observe the variation of channel properties depending on receiver location. For each receiver, amplitudes and phases of ail the possible rays form the transmitter to the receiver are traced to obtain impulse response. Statistical results for rms delay spread and power delay profiles for representative receiver location are given.

• Proceedings of the IEEK Conference
• /
• 2006.06a
• /
• pp.43-44
• /
• 2006

In this paper modeled UWB system transmission channel in apartment environment while furniture and household electric appliance etc. existed. We measured from 10MHz to 16.01GHz by using method of CIR and CTF in both LOS and NLOS environment. Also we design channel model simulator by MATLAB. The Result of Simulation shows BER characteristics by SNR.

• Journal of IKEEE
• /
• v.3 no.2 s.5
• /
• pp.196-203
• /
• 1999

In this paper, the DS(direct sequence)-CDMA and MC(multi-carrier)-CDMA, which are being researched recently as a synchronous IMT-2000 scheme for next-generation mobile multimedia communications, are studied in terms of BER(bit error rate) performance. The BER performance of MC-CDMA with EGB, MRC, and improved MMSEC detection scheme are analyzed and compared to that of conventional DS-CDMA adopting RAKE receiver through the computer simulations under the environments of synchronous IMT-2000 transmission channel. Not only single user case but also multiuser case is considered in the given system. As a result, it is shown that MC-CDMA with MMSEC detection outperforms all other schemes improved the $E_b/N_o$ by about 5 [dB] and 6 [dB] when the BER is $2{\times}10^{-3}$, for the indoor/outdoor fading channel and synchronous IMT-2000 transmission channel, respectively. Also in the multiuser case, MC-CDMA with MMSEC detection scheme exhibits better performance than all the other schemes.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.10 no.4
• /
• pp.15-24
• /
• 2014

This study conducted a computational fluid dynamics(CFD) analysis to find an appropriate diameter or sectional area of air ducts and fluid pipes which have an electromagnetic pulse(EMP) shied to protect indoor electronic devices in special buildings like military fortifications. The result shows that the optimized outdoor air intake size can be defined with either the ratio of the maximum air velocity in the supply duct to the air intake size, or the shape ratio of indoor supply diffuser to the outdoor air intake. In the case of water channel, the fluid velocity at EMP shield with the identical size of the pipe, decreases by 25% in average due to the resistance of the shield. The enlargement of diameter at the shield, 2 step, improves the fluid flow. It illustrated that the diameter of downstream pipe size is 1step larger than the upstream for providing the design flow rate. The shield increases friction and resistance, in the case of oil pipe, so the average flow velocity at the middle of the shield increase by 50% in average. In consideration of the fluid viscosity, the oil pipe should be enlarged 4 or 5 step from the typical design configuration. Therefore, the fluid channel size for air, water, and oil, should be reconsidered by the engineering approach when EMP shield is placed in the middle of channel.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.1
• /
• pp.7-21
• /
• 2017

Multiple antenna techniques employed in fourth generation mobile communication systems are affected on their performance mostly by transmission environments and antenna configurations. The performance of the indoor LTE(Long-term Evolution) MIMO(multiple input multiple output) has been rigorously evaluated with considering various diversity transmission schemes and propagation conditions in the paper. Specifically, MAC TP(medium access control throughput) and LTE system parameters related to the MIMO technique are analyzed for several indoor propagation conditions. The performance comparison between multiple antenna diversity mode and single antenna mode has been derived as well. The results performed in the paper give the guideline on antenna configurations of polarization diversity in LTE 2×2 MIMO for various indoor channel environments, and possibly are exploited by network operators and antenna manufacturers.