• Title/Summary/Keyword: 중계 노드 선택

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Performance Analysis of Best Relay Selection in Cooperative Multicast Systems Based on Superposition Transmission (중첩 전송 기반 무선 협력 멀티캐스트 시스템에서 중계 노드 선택 기법에 대한 성능 분석)

  • Lee, In-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.3
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    • pp.520-526
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    • 2018
  • In this paper, considering the superposition transmission-based wireless cooperative multicast communication system (ST-CMS) with multiple relays and destinations, we propose a relay selection scheme to improve the data rate of multicast communication. In addition, we adopt the optimal power allocation coefficient for the superposition transmission to maximize the data rate of the proposed relay selection scheme. To propose the relay selection scheme, we derive an approximate expression for the data rate of the ST-CMS, and present the relay selection scheme using only partial channel state information based on the approximate expression. Moreover, we derive an approximate average data rate of the proposed relay selection scheme. Through numerical investigation, comparing the average data rates of the proposed relay selection scheme and the optimal relay selection scheme using full channel state information, we show that the proposed scheme provides extremely similar performance to the optimal scheme in the high signal-to-noise power ratio region.

Outage Performance of Partial Relay Selection in Dual-Hop Decode-and-Forward Relaying Systems (듀얼 홉 디코딩 후 전달 중계 시스템에서 부분 중계 노드 선택 기법의 아웃티지 성능 연구)

  • Lee, In-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.3
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    • pp.40-47
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    • 2012
  • In dual-hop relaying systems, the conventional partial relay selection is based on the channel information only for the first hop. On the other hand, the efficient partial relay selection is based on the channel information for the hop with the minimum of the average channel powers for the first and second hops at each end-to-end link since the correlation coefficient between the end-to-end link quality and the link quality of the hop with the minimum of the average channel powers for the first and second hops is larger than that between the end-to-end link quality and the link quality of the other hop. In this paper, the outage probability of the conventional partial relay selection and the efficient partial relay selection in dual-hop decode-and-forward relaying systems is analyzed for non-identically distributed Rayleigh fading channels. Through numerical investigation, the outage performance of the efficient partial relay selection is compared with the outage performances of the conventional partial relay selection and the best relay selection based on all the channel information for the first and second hops.

Determination of Effective Relay Candidates for the Best Relay Selection in Wireless Systems in the Presence of Interference (간섭이 존재하는 무선 시스템에서 최적의 중계 노드 선택을 위한 효과적인 중계 노드 후보 결정 방법 연구)

  • Lee, In-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.12
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    • pp.2812-2817
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    • 2013
  • In this paper, an outage probability for the best relay selection in decode-and-forward relaying systems in the presence of interference is analyzed over Rayleigh fading channels. Based on the outage performance results, we propose a method to determine effective relay candidates for the best relay selection, where the effective relay candidates represent the relays except for relays that make no contribution to improving the performance. in all possible relays given in the system. By determining the effective relay candidates, the feedback overhead of channel state information and the energy consumption of relays can be significantly reduced while minimizing the performance degradation. In this paper, we provide important parameters that affect the determination of the effective relay candidates.

Exact Bit Error Rate Analysis of Partial Relay Selection in Dual-Hop Decode-and-Forward Relaying Systems over Rayleigh Fading Channels (레일레이 페이딩 채널을 고려한 듀얼 홉 디코딩 후 전달 중계 시스템에서 부분 중계 노드 선택 기법의 정확한 비트 오차율 분석)

  • Lee, Sangjun;Lee, In-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.1
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    • pp.42-49
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    • 2014
  • The conventional best relay selection based on all the channel information for the first and second hops in dual-hop systems has a large consumption of resources for channel feedback. In this paper, we analyze the average bit error rate for partial relay selection based on the channel information only for the first hop in dual-hop decode-and-forward relaying systems, where we assume independent Rayleigh fading channels. In particular, we provide an exact and closed-form expression for the average bit error rate of M-ary QAM. Also, through numerical investigation, the performance of the partial relay selection is compared with the performance of the best relay selection, and the performance is evaluated for different numbers of relays and various average channel power ratios for the first and second hops.

차세대 버퍼도움 중계전송 기법

  • Kim, Su-Min
    • Information and Communications Magazine
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    • v.33 no.4
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    • pp.92-98
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    • 2016
  • 본고에서는 5세대 이동통신 시스템의 유망기술 중 하나인 차세대 버퍼도움 (buffer-aided) 중계전송 기법의 핵심개념과 최신연구 동향에 대해서 알아본다. 먼저, 3개 노드로 구성되는 기본 중계기 네트워크에서 버퍼도움 중계전송의 원리와 관련 연구결과들을 살펴본다. 다음으로 다수 노드로 구성되는 다중 중계기 네트워크에서 기존 중계기 선택전송 기법 및 최신 버퍼도움 중계기 선택전송 기법에 대해서 비교하여 살펴본다. 마지막으로 차세대 버퍼도움 중계전송 기법응 다양한 환경에 적용한 응용 연구에 대해 살펴보고 본고를 마친다.

Performance Comparison of Relay Selection-Based Amplify-and-Forward Relaying Systems using Full or Partial Channel Information (전체 채널 정보와 부분 채널 정보를 이용하는 중계 노드 선택 기반 증폭 후 전달 중계 시스템의 성능 비교)

  • Lee, In-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.6
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    • pp.70-80
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    • 2012
  • In this paper, we consider the amplify-and-forward relaying systems with the relay selection (AF-RS) using full channel information (FCI) and using partial channel information (PCI), respectively, in which the direct communication link between a source and a destination is available. And, the outage probabilities for the AF-RS using FCI and using PCI are investigated in Rayleigh fading channels, respectively. We provide exact outage probabilities, tight outage probability lower bounds, and asymptotic outage probabilities, respectively. And also, we present coding gains achievable by the AF-RS using FCI and using PCI. Through numerical investigation, all the analytic expressions are verified, and the coding gains are respectively evaluated with different average channel powers for the first and the second hop as well as different numbers of relays.

Relay node selection scheme based on message distribution for DTN (DTN에서 메시지 분포에 따른 중계 노드 선택 기법)

  • Dho, Yoon-hyung;Lee, Kang-whan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.431-433
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    • 2016
  • In this paper, we propose an algorithm that analyzes characteristic nodes to select efficient relay nodes using message distribution. Existing delay-tolerant network (DTN) routing algorithms have problems with large latency and overhead on account of the deficiency of network information in an unsteady network. We must solve this problem, predict future networks using node state information, and apply a weight factor that changes according to the message distribution. Simulation results show that the proposed algorithm provides enhanced performance compared to existing DTN routing algorithms.

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Performance Analysis of Decode-and-Forward Relaying Based on Optimal Relay Selection (디코딩 후 전달방식에서 최적의 중계노드 선택방법에 대한 링크레벨 성능분석)

  • Lee, In-Ho;Kim, Dong-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.1A
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    • pp.36-43
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    • 2008
  • In this paper, we propose an optimal relay selection scheme for decode-and-forward relaying systems. The optimal relay selection minimizes the number of time slots used to relay source's signal and maximizes an end-to-end signal-to-noise ratio. However, decode-and-forward relaying systems require additional overhead for the optimal relay selection. Assuming independent and identically distributed Rayleigh fading channels, we provide exact and closed-form expressions for the outage probability of capacity and the bit error rate for decode-and-forward relaying systems with the optimal relay selection. It is shown that the analytic results are perfectly matched with the simulated ones. When the numbers of relay nodes are 2, 4, and 8, and the numbers of time slots for overhead are 1, 2, and 4, respectively, the proposed system achieves 1 dB, 2 dB, and 3 dB gains at 1% bit error rate, respectively, and 0.5 dB, 4 dB, and 12 dB gains at 1% outage probability for 1 bps/Hz, respectively, over the conventional decode-and-forward relaying system.

Study on Relaying Path Selection Using One-Hop Channel Information in Decode-and-Forward Relaying Based Multi-Hop Systems (디코딩 후 전달 중계 기반 다중 홉 시스템에서 하나의 홉 채널 정보를 이용하는 중계 경로 선택 기법 연구)

  • Lee, In-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.3
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    • pp.87-95
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    • 2013
  • In this paper, the outage probability of efficient partial relay selection(EPRS) using only one-hop channel information in multi-hop systems is analyzed in Rayleigh fading channels. In particular, we derive an exact and closed-form expression for the outage probability of decode-and-forward relaying based EPRS. In order to prove the usefulness of EPRS in multi-hop systems, we also analyze the correlation between the end-to-end signal-to-noise ratio(SNR) and the SNR for each hop at an arbitrary relaying path. Furthermore, through numerical investigation, we compare the outage performances for EPRS and the best relay selection using all channel information.

Stochastic Method of Relay Node Selection for Efficient Message Forward in DTN (DTN에서 효율적인 메시지 전달을 위한 확률적 중계 노드 선택 기법)

  • Dho, Yoon-hyung;Shin, Dong-Ryoul;Kim, Myeon-sik;Oh, Young-jun;Lee, Kang-whan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.105-106
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    • 2015
  • 본 논문에서는 DTN(Delay Tolerant Network) 환경에서 효율적인 메시지 전달을 위해 확률적으로 중계 노드를 선택하는 기법을 제안한다. DTN은 종단 간 연결이 불확실한 네트워크에서의 통신을 Store-Carry-Forward 방식을 사용하여 메시지를 목적 노드에 전달한다. 또한 종단 간 연결이 불확실한 상황에서도 중계 노드를 통해 메시지를 목적 노드에 전달하여 높은 전송률을 보장한다. 하지만 에피데믹(Epidemic) 라우팅이나 Spray and Wait 라우팅과 같은 기존 다중 복사 라우팅 알고리즘은 접촉한 모든 노드에게 메시지를 복사하여 메시지 복사로 인한 오버헤드가 높아진다. 반면에 PROPHET 라우팅과 같은 단일 복사 알고리즘은 적은 오버헤드를 발생시키지만 중계 노드 수 감소로 인한 메시지 전송률 감소 현상이 나타난다. 본 논문에서 제안하는 알고리즘은 기존 DTN 라우팅의 문제점을 보완하기 위해 확률적으로 노드 분포를 분석하여 현재 네트워크에 효율적인 메시지 복사 방식을 선택하여 작동한다. 본 논문에서는 제안하는 알고리즘이 기존 DTN 라우팅 알고리즘과 오버헤드와 전송률을 비교하여 더 효율적임을 증명한다.

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