• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.64-68
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• 2010

In this paper, we studied the novel synchronization algorithm for cooperative communication system over fading. We research mainly on the decode-and-forward scheme. Also, we inserted spreading sequence in origin data frame to control efficiently data synchronization. In mobile station, inserted spreading sequence in data frame passed through the corelation process. We had decide the delay value of received data through result of correlation process. In simulation, We applied that channel gain of three node had different value in various fading environment. Finally we will be possible to control the received data synchronization using result of corelation value in each node between relay to mobile station and base station to mobile station. The results of this paper can be applicable to the cooperative systems.

• International journal of advanced smart convergence
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• v.1 no.2
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• pp.1-11
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• 2012

IP-based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health care, home automation, environmental monitoring, industrial control, vehicle telematics, and agricultural monitoring. In all these applications, a fundamental issue is the mobility in the sensor network, particularly with regards to energy efficiency. Because of the energy inefficiency of network-based mobility management protocols, they can be supported via IP-WSNs. In this paper, we propose a network-based mobility-supported IP-WSN protocol called mSFP, or the mSFP: "Multicasting-supported Inter-Domain Mobility Management Scheme in Sensor-based Fast Proxy Mobile IPv6 Networks". Based on [8,20], we present its network architecture and evaluate its performance by considering the signaling and mobility cost. Our analysis shows that the proposed scheme reduces the signaling cost, total cost, and mobility cost. With respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 7% and the total cost by 3%. With respect to the number of hops, the proposed scheme reduces the signaling cost by 6.9%, the total cost by 2.5%, and the mobility cost by 1.5%. With respect to the number of IP-WSN nodes, the proposed scheme reduces the mobility cost by 1.6%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.154-161
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• 2013

This paper presents the signal-to-interference plus noise ratio (SINR) estimation of IEEE 802.16m WirelessMAN-Advanced mobile station with simulation and implementation results. The downlink signal of IEEE 802.16m has two kinds of A-Preambles: the PA-preamble and the SA-preamble. This paper proposes the efficient method of estimating SINR with A-Preambles, by measuring noise power from PA-preamble and measuring interference power and signal power from SA-preamble. The proposed SINR measurement block contains important features such as subcarrier phase rotation elimination and simplified dB transform. The result of this paper is integrated to ETRI's IEEE 802.16m test mobile station, used for decision of adaptive-modulation-and-coding (AMC) and hand-over. It showed good measurement performance in simulation and unified system link test also.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.151-163
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• 2014

The recent wearable device's applications concentrates on providing diverse services such as location based service, context aware service to the users. These various services are implemented by the interactions between the wearable device and the user. In the legacy system, the interaction requires certain explicit configuration from the user. If the user is unfamiliar with the IT technology, it will be impossible to get the wanted service. Therefore, a new autonomous communication concept among neighbor devices is essential for people who is unfamiliar with the IT technology. The implicit human computer interface enables the user to acquire the services, even though the user don't know the IT technology. In this paper, we propose two BLE based protocols (B-LIDx protocol, B-PniP). B-LIDx protocol is the protocol for locationing the mobile device in indoor. B-PniP is a zero-configure opportunistic direct M2M communication protocol between neighbor devices to achieve the autonomous communication concept with zero-configuration. The protocol's evaluations are performed by measuring the time for finding the location of a mobile device in actual environment and aligning the time spent in services using the B-PniP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.287-296
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• 2011

The white stick mainly used for visually impaired person has difficulty in providing location information and effective countermeasures for emergency situations encountered during walking as well as detecting floating obstacles on the ground. In this paper, we propose a machine-to-machine based intelligent walking assistance system for safe and convenient walking of the visually impaired. The proposed system consists of a walking assistance stick used by the visually impaired and a server supporting multiple stick users in remote places through mobile communication networks. The stick equipped with ultrasonic sensors, GPS(global positioning system) receiver and vibrator not only detects floating obstacles, but also offers stick users with present location identification utilizing a text-to-voice conversion technology. Besides providing geographic information, the server notifies the emergency locations of users to guardian and aid agency, and it provides log information during walking such as the place, time and the number of accidents. Test results with a developed prototype system have shown that the system properly performs the functions and satisfies overall system performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.2
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• pp.122-136
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• 1986

In this paper, the new modulation system, the digital phase-frequency hybrid modulation system is proposed for mobile radio communications. The error rate and the outage equation of PFSK(Phase-Frequency Shift Keying) signal transmitted through the fading channel has been derived considiering deversity techniques. The error rate and the outgae rate performances of PFSK system have been evaluated and shown in figures in terms of carrier-to-noise power ratio(CNR), fading figure, numbers of diversity branches, correlation coefficient among the diversity branches. And the performance of PFSK system is superior to that of QDPSK system. And by using diversity techniques, system performances can be improved 13dB above in CNR.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_1
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• pp.217-223
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• 2023

With the rapid advancement of technologies, need for different research fields where this technology can be used is also increasing. One of the most researched topic in computer vision is object detection, which has widely been implemented in various fields which include healthcare, video surveillance and education. The main goal of object detection is to identify and categorize all the objects in a target environment. Specifically, methods of object detection consist of a variety of significant techniq ues, such as image processing and patterns recognition. Anomaly detection is a part of object detection, anomalies can be found various scenarios for example crowded places such as subway stations. An abnormal event can be assumed as a variation from the conventional scene. Since the abnormal event does not occur frequently, the distribution of normal and abnormal events is thoroughly imbalanced. In terms of public safety, abnormal events should be avoided and therefore immediate action need to be taken. When abnormal events occur in certain places, real time detection is required to prevent and protect the safety of the people. To solve the above problems, we propose a modified YOLOv5 object detection algorithm by implementing dilated convolutional layers which achieved 97% mAP50 compared to other five different models of YOLOv5. In addition to this, we also created a simple mobile application to avail the abnormal event detection on mobile phones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.951-963
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• 1991

In this paper M-ary Psk system for digital land mobile radio utilized the raised-cosine filter instead of LPF with rectangular frequency characteristic as luniting channel bandwidth are implemented to measure their performance and effect of ISI and jitter. Also the error probability is calcylated on the condition of fast Rayleihg fading, cochannel interference and AWGN, It is found that QPSK and 8-PSK system with 2-branch diversity, can be improved by 3 or 5 time of spectral effciency respectively, comparinng with one of the non diversity QPSK and 8.PSK system.

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

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1700-1706
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• 2016

To improve the number of simultaneous transmissions of machine-to-machine traffic in a spread spectrum ALOHA channel, we propose a new spreading technique called doubly truncated cyclic code shift keying (DTCCSK). By truncating the codeset of cyclic code shift keying, DTCCSK freely adjusts the spreading factor and the symbol length. As a result, DTCCSK exhibits both a high spectral efficiency of M-ary signaling and low implementation complexity of a direct sequence.