• 전자공학회논문지B
• /
• 제30B권5호
• /
• pp.1-9
• /
• 1993

In this paper, we develop enhanced hypercube architectures and routing algorithms to realize arbitrary permutations in circuit switching. We prove that a hypercube is rearrangeable if one additional pair of links (one full-duplex communication line) is provided in only one dimesion of connections. We also prove that if each connection between two neighboring nodes consists of two pairs of links, the hypercube can handle two independent permutations simultaneously.

• 한국통신학회:학술대회논문집
• /
• 한국통신학회 1986년도 춘계학술발표회 논문집
• /
• pp.102-106
• /
• 1986

A digital telephone set for a voice/data PABX has been implemented with 3 semicustom IC`s, and one-chip microprocessor, etc. It adopts TCM(Time Compression Multiplexing) digital transmission method, and has the capacity of 144kb/s full-duplex digital transmission.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
• /
• pp.519-523
• /
• 2003

This paper describes the communication system of sequencing sorter. Generally sequencing sorter is a machine that sorts mails by delivery order. And designed sequencing sorter is composed of 5 physical modules. So, it is necessary to communicate with each module and to control this communication. A computer called Machine Management Computer, controls this. This paper is about the communication system with MMC and module controllers. This is PC-based, asynchronous full-duplex 4-wire serial systems. 3 protocol layers are presented and stop-and-wait flow control is adopted. Because designed sequencing sorter has to be operated high speed about 27,000 letters per hour, we analyzed the network traffic in the worst case. So, we could find that the communication system has to use above 115,200bps speed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권2호
• /
• pp.711-732
• /
• 2019

Many unmanned aerial vehicle (UAV) applications have been employed for performing data collection in facilitating tasks such as surveillance and monitoring objectives in remote and dangerous environments. In light of the fact that most of the existing UAV relaying applications operate in conventional half-duplex (HD) mode, a full-duplex (FD) based UAV relay aided wireless network is investigated, in which the UAV relay helps forwarding information from the source (S) node to the destination (D). Since the activated UAV relays are always floating and flying in the air, its channel state information (CSI) as well as channel capacity is a time-variant parameter. Considering decode-and-forward (DF) relaying protocol in UAV relays, the cooperative relaying channel capacity is constrained by the relatively weaker one (i.e. in terms of signal-to-noise ratio (SNR) or signal-to-interference-plus-noise ratio (SINR)) between S-to-relay and relay-to-D links. The channel capacity can be optimized by adaptively optimizing the transmit power of S and/or UAV relay. Furthermore, a hybrid HD/FD mode is enabled in the proposed UAV relays for adaptively optimizing the channel utilization subject to the instantaneous CSI and/or remaining self-interference (SI) levels. Numerical results show that the channel capacity of the proposed UAV relay aided wireless networks can be maximized by adaptively responding to the influence of various real-time factors.

• 전기학회논문지
• /
• 제56권3호
• /
• pp.629-631
• /
• 2007

In hands-free full-duplex communication systems, acoustic signals picked up by the microphones can be mixed with echo signals as well as noises, which may result in poor performance of the corresponding communication system. Also, the system performance may decrease further if the reverberation occurs since it is harder to estimate the impulse response of the demixing system. For blind source separation (BSS) in such cases, a time-frequency masking approach can be employed to separate undesired echo signals and noises, but, permutation ambiguities also should be solved for the echo cancellation. In this paper, we propose a new acoustic echo cancellation (AEC) approach utilizing the time-frequency masking and higher-order statistics, whereby a desired signal selection, based on coherence and third-order statistics (i.e., kurtosis), is introduced along with output signal normalization. Simulation results demonstrate that the proposed approach yields better echo and noise cancellation performances than the conventional AEC approaches.

• 한국측량학회:학술대회논문집
• /
• 한국측량학회 2004년도 추계학술발표회 논문집
• /
• pp.435-440
• /
• 2004

In this study, it is aimed to construct a remote home doctor system utilizing GIS technique. Remote home doctor system consists of three major compartments ; full-duplex communication system, visible communication system, and data backup system. On this system, a company request home doctor is connected with environment specialists and pollution control equipment company. The database in this system consists of spatial data and attribute data. Spatial data are made by topographic data and company location data. Attribute data consists in document data, status of company, products, amount of raw material used, odor discharge process, pollution discharge information and prevention equipments.

• 디지털산업정보학회논문지
• /
• 제10권3호
• /
• pp.119-125
• /
• 2014

Echo cancellation is required for a dual-duplex high speed communication such as digital subscriber line(DSL), in order to allow each individual loop to operate in a full duplex fashion. Echo cancellation was one of the most difficult aspects of DSL design, requiring high linearity and total echo return loss in excess of 70 dB. For a long and rapidly changing echo response, if the echo is cancelled by an adaptive echo canceller, the echo canceller needs more taps and its performance is decreased. But if the response is divided into several responses, which response is estimated by a adaptive digital filter and combined, the computation complexities are decreased and the performance is increased. Therefore, the adaptive multi-stage echo canceller is proposed to decrease the computation complexity and increase the performance of echo return loss, in which the echo canceller is composed of several stage echo canceller estimating each divided echo response. Through computer simulations, this multi-stage echo canceller is verified to have merits for high speed communications such as DSL application.

• 한국산학기술학회논문지
• /
• 제11권10호
• /
• pp.3756-3760
• /
• 2010

본 논문은 조가선을 이용한 전기철도의 전력선 통신을 위한 네트워크 설계를 제안한다. 전기철도에서 필수적인 전차선 및 조가선을 이용하여 전력선 통신에 대한 타당성 검토를 선행연구로 수행하였다. 이를 위해 우선 무가압상태에서 조가선에 신호결합기를 취부하여 양방향 데이터 통신을 구현하였다. 데이터 전송속도가 양호하게 나타났으며 이를 토대로 전력선 통신을 위한 주요 구성품을 제시하고 네트워크 설계를 제안하였다. 향후 네트워크 설계에 대한 타당성을 확보하기 위해 지속적인 연구를 수행하고자 한다.

• 한국통신학회논문지
• /
• 제40권2호
• /
• pp.273-284
• /
• 2015

본 논문에서는 상향링크와 하향링크가 공존하는 역 듀플렉스 셀룰러 네트워크 상황에서 단방향 기지국 협력을 통한 단사 간섭 정렬 타당성에 대한 연구를 하였다. 일반적인 안테나 개수와 사용자수에 따른 단사 간섭 정렬의 필요조건과 충분조건을 제시하였고, 이어서 특정 조건을 만족하는 네트워크에서 간략화 된 충분조건을 제시하였다. 특히 대칭 네트워크 상황에서는 단사 간섭 정렬의 필요충분조건을 제시하였고, 각 셀 당 두 명의 사용자가 존재하는 대칭 네트워크 상황에서는 닫힌 형태의 필요충분조건을 규명하였다. 제안한 단방향 기지국협력을 통해 합 자유도를 크게 증가시킬 수 있으며, 모의실험을 통해 상용 신호 대 잡음비 영역에서 합 전송률을 획기적으로 개선 할 수 있음을 확인 하였다.

• 한국전자파학회논문지
• /
• 제27권4호
• /
• pp.369-376
• /
• 2016

본 논문에서는 스펙트럼 효율 향상을 위하여 5G(Generation) 후보 변조 기술을 사용하는 SSD(Simultaneous Single band Duplex) 시스템을 설계하고, 각 시스템의 성능을 평가하고 비교 분석한다. 특히, 제안하는 5G 이동통신을 위한 후보 변조기술을 사용하는 SSD 시스템에 HPA(High Power Amplifier) 비선형성을 고려하여 시뮬레이션을 수행한다. 시뮬레이션의 결과로 SSD-OFDM, SSD-UFMC, SSD-FBMC 시스템은 HPA 비선형성에 의해 성능 열화가 심화되었지만, 동일한 HPA 비선형 조건에서 각각 시스템은 서로 유사한 성능을 내었다. 즉, 각각의 변조기술은 유사한 PAPR(Peak to Average Power Ratio) 특성을 갖는다. 이러한 결과로, 자기간섭신호(self-interference)의 비선형 왜곡이 심화될 경우, 자기간섭 제거가 어렵다는 것을 확인할 수 있다. 즉, 제안하는 SSD 시스템에서 HPA 비선형에 의한 영향을 줄이기 위해 PAPR을 저감시키는 것이 중요하다.