• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.147-153
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• 2018

Beacon enables one to measure distance indoors based on low-power Bluetooth low energy (BLE) technology, while GPS (Global Positioning System) only can be used outdoors. In measuring indoor distance using Beacon, RSSI (Received Signal Strength Indication) is considered as the one of the key factors, however, it is influenced by various environmental factors so that it causes the huge gap between the estimated distance and the real. In order to handle this issue, we propose the adaptive ANN (Artificial Neural Network) based approach to measuring the exact distance using Beacon. First, we has carried out the preprocessing of the RSSI signals by applying the extended Kalman filter and the signal stabilization filter into decreasing the noise. Then, we suggest the multi-layered ANNs, each of which layer is learned by specific training data sets. The results showed an average error of 0.67m, a precision of 0.78.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.119-130
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• 2015

In the recent gaming industry, the paradigm has been changed with upcoming core-platform as time goes by. Arcade, console, PC online and smart device platforms are representative ones. In recently, the platform is changed to multi-platform which connecting to smart device and other platforms. Besides, the multi-platform without PC is up-coming. This paper suggests that a kind of multi-platform which connecting from smart devices to arcade devices be aware of lack of continuous. It provides a new arcade gaming condition connecting to smart devices, then supplies online network conditions to the arcade gaming machine. The original arcade game was lack of continuous and the game platform was so simple, but now, it could be focused from players by connecting to smart devices to increase the gaming machines' continuity. Furthermore, Bluetooth communication module and wireless Wi-Fi communication module are used to adapt various communication environments. The Unity3D engine would make contents' expandability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.25-31
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• 2017

The indoor location based service proposed in the study was assigned to target a moving user. Positioning in the outdoor environment is accurate while using GPS. However, in an indoor environment, positioning is inaccurate and difficult. In order to overcome this, studies of various techniques for positioning based on wireless communication such as Wi-Fi, Zigbee and Bluetooth are being performed. The RSSI value and the delivery signal of the bluetooth beacon are measured according to the distance, and to a database. It was applied calculating the value for the average RSSI and the RSSI filtering feedback. Filtering is used to reduce the error of the RSSI values that are measured at long distance. When average and feedback filtering coefficient are set with 0.5, irregular and highly RSSI values are decreased. As the distance increases, the range of error is confirmed to have a reduction when using a distance calculation correction algorithm. Finally, when using the RSSI measurement results filtering, it corrects an unstable signal. Also, the distance correction algorithm is used to reduce a range of errors.

• Journal of IKEEE
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• v.24 no.3
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• pp.838-844
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• 2020

In this paper, we propose an efficient Viterbi processor using Joint Viterbi detection and decoding (JVDD) algorithm for a for bluetooth low energy (BLE) system. Since the convolutional coded Gaussian minimum-shift keying (GMSK) signal is specified in the BLE 5.0 standard, two Viterbi processors are needed for detection and decoding. However, the proposed JVDD scheme uses only one Viterbi processor by modifying the branch metric with inter-symbol interference information from GMSK modulation; therefore, the hardware complexity can be significantly reduced without performance degradation. Low-latency and low-complexity hardware architecture for the proposed JVDD algorithm was proposed, which makes Viterbi decoding completed within one clock cycle. Viterbi Processor RTL synthesis results on a GF55nm process show that the gate count is 12K and the memory unit and the initial latency is reduced by 33% compared to the modified state exchange (MSE).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.464-470
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• 2013

These days, with increasing interest about the health care, research about standard for transmitting/receiving data of health device has been actively conducted. Standardization and testing / certification is underway through the IEEE 11073 PHD, Health Level Seven and the Continua Health Alliance, it'll continue to be more research and experiments in the future. In this paper, we introduce the IEEE 11073 PHD standards for exchange of remote health information and the Bluetooth Health Device Profile(HDP) for health device profile of the Bluetooth technology, also we conducted experiments about exchange health information between health device and smart device which are adapted the IEEE 11073 PHD and Bluetooth HDP. Transmitting/receiving of the IEEE 11073 PHD standard protocol using the Bluetooth HDP profile between health device and smart device can be known by this experiment, and it expect to implement variety of remote medical services through health device supporting these standards in future.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.31-40
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• 2017

The rise of eco-friendly personal electric mobility is a worldwide trend and the first Korean-made IT convergence electric skateboard, Youth Board, is developed to lead the trend. Youth Board is remotely controllable using either Youth Wearable Controller or Youth App through Bluetooth v4.0 communication, can speed up to 25 km/hr, and operating time is approximately 1.5 hr. A LED display located in the front side of Youth Board deck shows three different states to a rider for user convenience: remaining battery SOC, current driving speed, and braking amount. Indoor EMC test results between Youth Board and Youth Wearable Controller and outdoor Youth Board driving test results are analyzed. In particular, driving test results show the maximum current output is about 15% lowered compared to the other competitor electric skateboard and it lessens the power burden of the motor ESC. These results show Youth Board's usefulness as a personal mobility in the sense of small, light, and inexpensive aspects.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.803-810
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• 2017

Currently, every person possesses a smart phone due to the development of the IT industry. There is an improper situation in which a smart phone is not set in silent mode, such as a lecture room, a library, and a theatre hall. The proposed system automatically automates the function of smart phones where they are designated as a public place or etiquette area and automatically return the function of the smartphone if they deviate from the location of the site. It is also equipped with a combination of autonomous devices and services, based on Bluetooth communications, which are applied to ultra-light low-power IoT(Internet of Things) devices, and has features that allow diverse types of features and services to be added without requiring deformation of the hardware.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.958-966
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• 2012

This paper presents a compact bluetooth/WiFi dual-mode dual-band RF front-end module(FEM) is realized by low temperature co-fired ceramic(LTCC) technology. The proposed RF front-end module consists of a diplexer, baluns in the LTCC substrate, and an SPDT switch, an SP3T switch on the LTCC substrate. In order to reduce the module size and increase integration level, the proposed diplexer and balun are designed using LC lumped elements. The parasitic elements caused by coupling effect between metal pattern layers and ground plane layer are considered during the design. The fabricated dual-mode RF front-end module has 13 pattern layers including three inner ground layers and it occupies less than $3.0mm{\times}3.7mm{\times}0.66mm$.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.113-118
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• 2006

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency rage of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses ,however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using Sendust, $Al(OH)_3$, and CPE. The double-layered EM wave absorber with thickness of 1.5 mm has absorption ability more than 10 dB at 2.4 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1103-1108
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• 2010

In this paper, Frequency Synthesizer which is widely used for FH-SS system is proposed and the experimental results are analyzed. The performance of the DPLL(Digital Phase-Locked-Loop), which is the main part of the Synthesizer is analyzed by the computer program. Using Maxplus-II tool provided by altera. co., ltd, each part of the DPLL is designed and all of them is integrated into EPM7064SLC44-10 chip. And the simulation results are compared with the characteristics of the implemented circuits for analysis. And the experiential results show that the N value of the loop filter is toggled to adjacent N value, which result in phase jitter of the output. It can be resolved by increasing DCO(Digital Controlled oscillator) clock rate.