• Information and Communications Magazine
• /
• v.32 no.4
• /
• pp.29-35
• /
• 2015

본고에서는 최근 전 세계적인 화두가 되고 있는 사물 인터넷, 그 중에서도 가장 먼저 시장이 커지고 있는 스마트 홈에 대해 알아본다. 스마트 홈의 경우 많은 수의 사물인터넷 디바이스 들의 연결이 중요한데 많은 수의 노드를 연결하기 위해서는 기존의 유선방식 이외에 무선 컨넥티비티가 선행 구현되어야한다. 따라서 이를 구현하기 위한 무선 컨넥티비티에 대해서도 알아본다.

• Electronics and Telecommunications Trends
• /
• v.11 no.4 s.42
• /
• pp.89-101
• /
• 1996

본 논문은 IEEE 802.11 프로토콜 구성과 무선 근거리 통신망의 매체접근제어(Media Access Control: MAC), 공유자원인 무선채널을 액세스하기 위하여 사용하는 대표적인 MAC방식을 분류하여 설명하였고, MAC의 핵심이 되는 매체접근제어 프로토콜인 DFWMAC(Distributed Foundation Wireless MAC)의 핵심기능에 대하여 소개한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.05a
• /
• pp.205-209
• /
• 2000

Modem wireless communication equipments provides various multimedia and aims at the development of low-power, minimum size and weight, and low-cost implimentations. Because of the heterodyne architecture which was invented many decades ago in the wireless communication system using too many components, it was difficult to make it small, compact and On-Chip so it does not proper for future communication. That gives rise a new developing architecture, so called, Direct Conversion. Because The Direct Conversion down-converts the wireless frequency band to baseband directly, it does not need using additive components and has a merit of reduction in power dissipation. We describes the Direct Conversion architecture and DC-Offset, which must be solved, theorectically and predicts system performance enhancement when adopt the AC-Coupling method.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.4B
• /
• pp.192-198
• /
• 2008

In this paper, we propose a scheme that improves the transmission performance of realtime multimedia data in wireless Local Area Network (LAN) environment, through the dynamical control of Transmission Opportunity (TXOP) period of the IEEE 802.11e HCCA Medium Access Control (MAC). The existing schedulers which determine the frame transmission time and its duration could not appropriately cope with the change of physical transmission rate, since the TXOP period has remained unchanged with the change of transmission rate of the wireless station. Our scheme is devised to keep the transmission performance of real-time multimedia data effectively unchanged by making TXOP period be extended when the transmission rate gets reduced. The proposed scheme is experimented along with IEEE 802.11e reference model using NCTUns simulator, which shows that the multimedia data is effectively delivered with the change of transmission rate as the distance between the wireless station and its access point increases.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.6
• /
• pp.617-623
• /
• 2016

Recently, IoT technology has been applied to the control of appliances in the home, and information about temperature, humidity, etc. is collected and the application of the system to control the indoor environment automatically is increasing. Currently, the network configuration of IoT devices is mainly used to connect IoT devices to the Internet through wireless gateways. Since such a method is dependent on a gateway, there are limitations in providing various services. Therefore, this paper proposes an independent method of gateway by using IoT network without using gateway by applying long distance wireless communication technology. IoT devices using the proposed long distance wireless internet technology can connect to a remote server and provide mobility that can not be supported by existing methods, thereby providing more various services. The performance evaluation of the proposed network configuration method is compared with the delay time and the amount of data generated in the existing network method constituted by the gateway and the proposed network configuration method respectively. Experimental results show that the proposed method decreases the delay time and the amount of data generated by the gateway.

• Electronics and Telecommunications Trends
• /
• v.37 no.4
• /
• pp.60-69
• /
• 2022

So far, artificial intelligence (AI)/machine learning (ML) has produced impressive results in speech recognition, computer vision, and natural language processing. AI/ML has recently begun to show promise as a viable means for improving the performance of 5G mobile telecommunication systems. This paper investigates standardization activities in 3GPP and O-RAN Alliance regarding AI/ML applications on mobile telecommunication system. Future trends in AI/ML technologies are also summarized. As an overarching technology in 6G, there appears to be no doubt that AI/ML could contribute to every part of mobile systems, including core, RAN, and air-interface, in terms of performance enhancement, automation, cost reduction, and energy consumption reduction.

• Electronics and Telecommunications Trends
• /
• v.39 no.3
• /
• pp.87-97
• /
• 2024

With the timeline released by ITU-R (Radiocommunication Sector of the International Telecommunication Union), research and development activities for the International Mobile Telecommunications for 2030 and beyond (IMT-2030) are now in full swing. We provide an overview of the general process of making global core specifications for next-generation mobile systems and summarize the ITU-R Recommendation of the IMT-2030 Framework. The ITU-R Recommendation focuses on IMT-2030 usage scenarios and related capabilities. The expectations of 3GPP (Third Generation Partnership Project) activities for the proposal of candidate IMT-2030 global core specifications to the ITU-R are also discussed. The launch of IMT-2030 for commercial purposes is expected to begin in 2030.

• 정보화사회
• /
• s.90
• /
• pp.8-15
• /
• 1995

최근 들어 무선통신 특히 주파수공용시스템은 산업용 이동통신서비스를 가장 효율적으로 수행할 수 있는 무선통신방식으로 각광받고 있다. 국내에서는 주파수 자원의 부족과 지속적으로 증대되는 산업용 이동통신 수요를 충족시키기 위해 TRS 의 도입과 확산이 활발해지고 있으며, 금년말로 예정되어 있는 TRS디지털 제2전국사업자 선정을 앞두고 업계의 관심이 증폭되고 있다. 이에 현재 TRS업무에 종사하고 있거나 TRS에 대해 알고자 하는 독자층을 대상으로 구체적인 기술사항을 논의하기보다는 일반적 이해의 폭을 넓히는 방향으로 서술했다.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1557_1558
• /
• 2009

다양한 환경에서 무선 센서노드 시스템이 적용됨에 따라 해당 시스템의 통신 방식이 중요해 지고 있다. 이에 본 논문은 통신 방식 중 진폭 변조 방식을 사용한 통신방식에서의 복조회로를 제안하였다. 보다 효율적인 복조를 위해 동적 기준전압 방식의 복조회로를 구현함으로써 저전압 입력 시에도 복조가 가능하게 하여 센서노드의 인식거리를 확대했다. 또한 제안된 회로를 시스템에 직접 적용하여 실제 진폭변조신호의 복조가 가능한지 검증함으로써 센서노드 시스템에 적용 가능함을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.10a
• /
• pp.172-175
• /
• 2000

본 논문에서는 무선마이크용 특정소출력무선기기의 송수신단을 설계하고 제작하여 특성을 측정하였다. 무선마이크용 특정소출력무선기기의 주파수 대역 740.000~752.000MHz를 사용하였고, 점유주락수대폭의 허용치 200kHz, 최대주파수편이 $\pm$75kHz를 만족하도록 설계하였다. PLL Synthesized, 주파수 변조, Dual Conversion 방식을 사용하였으며 Compander Type은 2:1이다. 설계된 무선마이크 시스템의 출력은 10mW이하이고, 50-20,000Hz의 주파수 응답을 가지며 Hi-fi Audio를 전송할 수 있다. 송수신단의 Total Harmonic Distortion 은 1.5% 이하이다.