• Title/Summary/Keyword: mRelay

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Approximated Outage Probability for ADF Relay Systems with Burst MPSK and MQAM Symbol Transmission

  • Ko, Kyunbyoung;Lim, Sungmook
    • International Journal of Contents
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    • v.11 no.1
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    • pp.7-14
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    • 2015
  • In this paper, we derive the outage probability for M-ary phase shifting keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) burst transmission (BT) of adaptive decode-and-forward (ADF) cooperative relay systems over quasi-static Rayleigh fading channels. Within a burst, there are pilot symbols and data symbols. Pilot symbols are used for channel estimation schemes and each relay node's transmission mode selection schemes. At first, we focus on ADF relay systems in which the probability density function (PDF) is derived on the basis of error events at relay nodes corresponding to channel estimation errors. Next, the average outage probability is derived as an approximate expression for an arbitrary link signal-to-noise ratio (SNR) for different modulation orders. Its accuracy is demonstrated by comparison with simulation results. Further, it is confirmed that BT-ADF relay systems with pilot symbol based channel estimation schemes enables to select correctly decoded relay nodes without additional signaling between relay nodes and the destination node, and it is verified that the ideal performance is achieved with small SNR loss.

Average SER Performance Analysis for Opportunistic Amplify-and-Forward Relay Systems (OAF 시스템의 정확한 심볼 오류 성능 분석)

  • Nam, Sang-Ho;Ko, Kyun-Byoung;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.4
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    • pp.1-8
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    • 2012
  • This paper presents a method for obtaining an exact average symbol error rate (ASER) of M-ary Phase Shift Keying (MPSK) for opportunistic amplify-and-forward (OAF) relay systems over Rayleigh fading channels. This is based on the relay selection probability when a relay is selected as the best one with respect to the received signal-to-noise ratio. We then derive the modified moment generating function (MGF) for OAF relay systems by taking the given relay selection probability into consideration. Based on the modified MGF, we derive the exact ASER which accurately explicates OAF relay system characteristics. Our results confirm that the derived ASER provides a tight upper bound for OAF relay systems.

A Study on the Marathon Program Production using LTE Network (LTE망을 이용한 마라톤 생방송 프로그램 제작에 관한 연구)

  • Cho, Yong-Suck;Moon, Myung-Sok;Choi, Seong-Jhin
    • Journal of Satellite, Information and Communications
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    • v.12 no.2
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    • pp.15-20
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    • 2017
  • A conventional TV relay broadcast is a method of transmitting a program by means of a microwave, a leased wire, or a satellite. With the latest advances in LTE network, a relay approach using LTE mobile communications network has become increasingly competing with the traditional TV relay broadcast method. Since 2012, TV Chosun has been using the LTE network for marathon production, and channel A has also broadcast a marathon production broadcast using the LTE network. Therefore in this paper, we investigated the marathon relay method using LTE mobile communications network and compared with the traditional TV marathon relay method, and then suggested the optimum method for the marathon relay.

A Study of Over Voltage Ground Relay Operation Status at Opening of No-load Charged Cable (무부하 충전케이블 개방시 잔류전압에의한 과전압계전기 동작현상 연구)

  • Kim, Yeong-Han;Choi, Jong-Hyuck;Yoon, Ki-Seob
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.185-187
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    • 2000
  • Fault current is flowed into 154/23kV M. Tr when line-to-ground fault occurs in power system. NGR(Neutral Grounded Reactor) is set up in order to prevent M.Tr fault by limiting magnitude of fault currents. Here, disconnection of NGR causes voltage increase by L-C resonance and line-to-ground fault in an unearthed system results in voltage increase at healthy phases. So Over Voltage Ground Relay(OVGR) is used for tripping M.Tr. Also, buses at second phases of M.Trs are all connected with section circuit breakers closed for the purpose of parallel operation and load shedding. In case of speciality buses are comprised of power cable in part for GIS connection. When no-load charged cable or bus is open by a section CB, unbalanced voltage charged on the bus is induced. Also discrepant opening time for circuit breakers on different phases gives rise to unbalanced zero sequence voltage. It was observed that this zero sequence voltage detected in the 22.9kV P.T (Potential Transformer for bus) mal-operated 59GT and tripped M.Tr. The zero sequence voltage of which vanishing time is longer than relay operating time came out by EMTDC simulation. Also, it was shown that the voltage waves of actual test are similar to those of simulation. On the basis of above results, R-C circuit complement on the relay without any effect on a power system made operating time of the relay longer than vanishing time of distorted waves. Consequently, operating time of the relay was delayed and magnitude of distorted waves was decreased by increasing time constant of the relay.

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Analysis of the congestion control scheme with the discard eligibility bit for frame relay networks (프레임 릴레이망에서의 DE 비트를 사용하는 혼잡제어 방식의 성능해석에 관한 연구)

  • 이현우;우상철;윤종호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.9
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    • pp.2027-2034
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    • 1997
  • Frame relay is a fast packet switching technology that performs relaying and multiplexing frames with variable lengths over a wide area link at the T1 or E1 speed, by elminating error and flow control in the network. In frame relay networks, congestion control is typically performed through the rate enforcement with a discard eligibility (DE) bit, and the explicit negative feedback meachanisms using explicit congetion notification bits. In this paper, we consider the congestiong control scheme using the rate enforcement mechanism with DE bit for frame relay network. Assuming that each frame with exponentially distributed length arrives according to the Poission fashion, we can treat the frame relay switch as an M/M/1/K priority queueing system with pushout basis. We analyze and present the blocking probabilities and waiting time distributions of frames.

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Average Data Rate Analysis for Data Exchanging Nodes via Relay by Concurrent Transmission (데이타 교환 노드의 동시 전송 릴레이 이용을 위한 평균 데이터 전송률 분석)

  • Kwon, Taehoon
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.6
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    • pp.638-644
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    • 2018
  • Relay systems have recently gained attentions because of its capability of cell coverage extension and the power gain as the one of key technologies for 5G. Relays can be exploited for small-cell base stations and the autonomous network, where communication devices communicate with each other cooperatively. Therefore, the relay technology is expected to enable the low power and large capacity communication. In order to maximize the benefits of using a limited number of relays, the efficient relay selection method is required. Especially, when two nodes exchange their data with each other via relay, the relay selection can maximize the average data rate by the spatial location of the relay. For this purpose, the average data rate is analyzed first according to the relay selection. In this paper, we analyzed the average data rate when two nodes exchange their data via dual-hop decode and forward relaying considering the interference by the concurrent transmission under Nakagami-m fading channel. The correctness of the analysis is verified by the Monte Carlo simulation. The results show that the concurrent transmission is superior to the non-concurrent transmission in the high required data rate region rather than in the low required data rate region.

Outage Probability of Transmit Maximum-Ratio-Combining and Relay Selection Diversity for Amplify-and-Forward Relaying System (증폭 후 전달 릴레이 시스템을 위한 송신 Maximum-Ratio-Combining과 릴레이 선택 다이버시티에 대한 Outage 확률 분석)

  • Min, Hyun-Kee;Lee, Sung-Eun;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.13-18
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    • 2008
  • In this paper, we consider an amplifying-and-forward(AF) dual-hop relaying system where the source node transmits to a destination node with the help of R relay nodes. We assume that the source node equips M transmit antennas, but only one antenna is equipped at the each node of relay and destination. The outage probabilities are presented when the transmit maximum-ratio-combining(MRC) is used at the source-relay(S-R) links, and the best relay selection, which selects only one relay that contributes the most to the received signal-to-noise ratio(SNR) as active relay, is combined. Simulation results validate these analytical results.

Fair Relay Selection in Regenerative OFDMA Relay Network (재생 OFDMA 중계 네트워크에서의 공평한 중계기 선택)

  • Jeong, Ha-Rin;Kim, Jin-Su;Lee, Jae-Hong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.2
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    • pp.11-17
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    • 2009
  • This paper presents a new adaptive relay selection scheme for a regenerative orthogonal frequency division multiplexing access(OFDMA) relay network with fairness constrains. In the Proposed scheme, we select the best M relays out of a set of K potential relays to maximize system capacity. Among these selected relays, subcarriers are reallocated to satisfy fairness constraints as well as to minimize the degradation of the system performance. Afterwards, power allocation is performed for each subcarrier based on the water-filling method to enhance the performance improvement. By using the trade-off relationship between the system capacity and the fairness, the modified version of proposed scheme is also investigated.

Optimized Relay Node Deployment and Resource Allocation in LTE-Advanced Relay Networks

  • Fenghe, Huang;Joe, In-Whee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2014.04a
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    • pp.146-148
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    • 2014
  • In LTE-Advanced (LTE-A) networks, Relay nodes (RN) are used to improve the system coverage. However, it also brings new kind of interference to users which reduces the system performance. In this paper, we use an optimization relay node deployment to reduce the interference as much as possible and resource allocation to improve the user throughput. Our simulation results show our method is able to improve the user SINR and throughput.

Outage Probability of Device-to-Device MIMO Relay Systems with Imperfect Channel Estimation

  • Wei, Liang wu;Shao, Shi Xiang
    • IEIE Transactions on Smart Processing and Computing
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    • v.2 no.2
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    • pp.67-76
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    • 2013
  • Under an imperfect channel estimation, a Device-to-Device (D2D) communication framework based on MIMO relay technology is presented. The model consists of a D2D pair equipped with M antennas and a relay equipped with N antennas as well as a cellular user equipped with M antennas. The outage probability under different relaying protocols (i.e. AF and DF protocol) with and without considering a direct link was derived. The actual and theoretical outage probability of the five links under different antenna numbers was emulated. The number of user antennas and channel estimation error was analyzed carefully to determine their impact on the outage probability of a system. The simulation verified the theory analyses and the results showed that MIMO relaying improves the D2D communication system performance.

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