• Electronics and Telecommunications Trends
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• v.30 no.1
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• pp.94-101
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• 2015

이동통신 기반 IoT(Internet of Things) 관련 표준들은 3GPP와 ETSI를 중심으로 제정되어 왔으나 2012년부터 표준의 중복을 회피하고 단일화된 표준을 통해서 IoT 시장을 성장시키고자 oneM2M이라는 국제적 협의체가 구성되었으며, 최근 Release 1 표준을 발표하는 등 IoT 표준을 사실상 주도하고 있다. Mason과 Machina 리서치에 따르면 2020년에는 동시 연결된 M2M(Machine to Machine)/IoT 장치들의 수가 21억개에 달할 것이고, 이것들이 동시에 200억개의 통신 연결을 생성할 것이다. 이런 수많은 장치들을 관리하기 위한 표준으로 OMA(Open Mobile Alliance)에서는 LWM2M(Lightweight M2M)를 제정하였다. 또한 이런 장치들은 센서들과 같이 연산능력과 배터리에 제약이 많아서 이것을 극복할 수 있는 메시지 프로토콜로 IETF에서는 CoAP 표준을 제정하였다. oneM2M에서도 CoAP과 LWM2M 표준을 채택하였고, 이를 기반으로 한 단말과 응용서비스 관리 기능이 확대될 것으로 기대된다. 본고에서는 이동통신 기반 IoT 표준 동향과 LWM2M 기반 단말 관리 규격에 대해 살펴본다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.65-73
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• 2008

Security layer of the Cdma2000 1x EV-DO is currently completing standard (C.S0024-A v2.0). Accordingly, a hardware security devices, that allows to implementation requirement of the security layer described in standard document, is required to apply security function about data transferred between AT and AN of then Cdma2000 1x EV-DO environment. This paper represents design of hardware device providing EV-DO security with simulation of the security layer protocol via the FPGA platform. The SHA-1 hash algorithm for certification and service of packet data, and the AES, SEED, ARIA algorithms for data encryption are equip in this device. And paper represents implementation of hardware that applies optionally certification and encryption function after executing key-switch using key-switching algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12A
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• pp.2027-2035
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• 2001

In this paper, we present an audio stream delivery using the AMR (Adaptive Multi-Rate) coder that was adopted by ETSI and 3GPP as a standard vocoder for next generation IMT-2000 service in which includes combined sender (FEC) and receiver reconstruction technique in the Internet. By use of the media-specific FEC scheme, the possibility to recover lost packets can be much increased due to the addition of repair data to a main data stream, by which the contents of lost packets can be recovered. The AMR codec is based on the code-excited linear predictive (CELP) coding model. So we use a frame erasure concealment for CELP-based coders. The proposed scheme is evaluated with ITU-T G.729 (CS-ACELP) coder and AMR - 12.2 kbit/s through the SNR (Signal to Noise Ratio) and the MOS (Mean Opinion Score) test. The proposed scheme provides 1.1 higher in Mean Opinion Score value and 5.61 dB higher than AMR - 12.2 kbit/s in terms of SNR in 10% packet loss, and maintains the communicab1e quality speech at frame erasure rates lop to 20%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.445-453
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• 2016

This paper presents the implementation and design of the 1T-1R wireless HD video streaming systems over 28 GHz mmWave frequency using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system uses USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transceived from USRP RIO up or down converts to 28 GHz by using self-designed 28 GHz RF transceiver modules and it is finally communicated HD video data through self-designed $4{\times}8$ sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express ${\times}4$ to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 25.85 dBc and to transceive HD video in experiment environment anywhere.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.209-214
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• 2014

IMS(IP Multi-Media Subsystem) is in the limelight as the Integrated wire and wireless Systems because of a sudden increase of smart mobile devices and growth of multimedia additional services such as IPTV. The structure of IMS is designed as a session control layer to provide various multimedia summative service using SIP based on IP communication network in order to carry out set-up, change and release by NGN of course, the existing voice services. But now It is broadly substituting in the IPTV, wire phone company and it is substituted in internet platform base on the soft-switch in currently. Especially, in currently, 4G LTE in a mobile communication company is rapidly growing in market. Therefore, in this study, we had designed and developed to the main prosser that can admit to 1000 user over and SIP gateway which can link the IMS Core that can link SIP Device which adopt the standard protocol on the SIP and to provide variable multimedia services.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.4
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• pp.23-31
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• 2018

This paper presented the implementation and design of the 2T-2R wireless HD video streaming systems over 1.7 GHz frequency band using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system used USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transmitted from USRP RIO up or down converts to 1.7 GHz by using self-designed 1.7 GHz RF transceiver modules and it is finally communicated HD video data through self-designed 2x9 sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express x4 to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 32 dBc and to transmit and receive HD video in experiment environment anywhere. The proposed hybrid beam forming system could be used not only in the future 5G mobile communication systems under 6 GHz frequency band but also in the systems over 6 GHz frequency band like ones in mmWave frequency bands.

• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.34-39
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• 2001

An adaptive multi-rate (AMR) speech coder was adopted as a standard of W-CDMA by 3GPP and ETSI. The AMR coder is based on the CELP algorithm operating at rates ranging from 12.2 kbps down to 4.75 kbps, and it is a source controlled codec according to the channel error conditions and the traffic loading. In this paper, we implement the DSP S/W of the AMR coder using OakDSPCore. The implementation is based on the CSD17C00A chip developed by C&S Technology, and it is tested using test vectors, for the AMR speech codec, provided by ETSI for the bit exact implementation. The DSP B/W requires 20.6 MIPS for the encoder and 2.7 MIPS for the decoder. Memories required by the Am coder were 21.97 kwords, 6.64 kwords and 15.1 kwords for code, data sections and data ROM, respectively. Also, actual sound input/output test using microphone and speaker demonstrates its proper real-time operation without distortions or delays.