• Title/Summary/Keyword: two-way relay

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Relay Selection Schemes in Network-Coding based Two-Way Relay Communication to Improve Performance (성능향상을 위한 네트워크 부호화 기반 양방향 중계기 통신에서의 릴레이 선택 기법)

  • Lee, Jin-Hee;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.9 no.5
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    • pp.7-13
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    • 2009
  • In This Paper, we propose relay schemes for network-coding based two-way relay communication in multi relay channel. Two-way relay channel communication is a bi-directional communication that two users exchange their data with the help of a relay. Network-coding based Two-way relay communication can achieve more throughput compared to conventional two-way relay communication. In this paper, we propose relay selection schemes to provide maximum performance considering instantaneous signal-to-noise in multi-relay channel. Simulation results show that the proposed relay selection schemes can provide diversity order according to the number of relays.

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Interference Alignment in Two-way Relay Channel with Compute-and-Forward

  • Jiang, Xue;Zheng, Baoyu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.2
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    • pp.593-607
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    • 2016
  • This paper analyzes interference alignment in the two-way relay network with compute-and-forward in both single relay and multiple relays networks. The advantages of compute-and-forward over other relaying strategies are that it can relay only linear combinations of the useful signals and remove the noise. The algorithm proposed in this paper adopts the criterion of maximum SINR to derive the pre-coding matrix. The experimental results show that the performance of interference alignment in two-way relay channel via compute-and-forward is better than that of amplify-and-forward, and the total sum rate in the two-way multiple relay networks is larger than that in the two-way single relay networks.

Secure Transmission for Two-Way Vehicle-to-Vehicle Networks with an Untrusted Relay

  • Gao, Zhenzhen
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.6
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    • pp.443-449
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    • 2015
  • This paper considers the physical layer security problem for a two-way vehicle-to-vehicle network, where the two source vehicles can only exchange information through an untrusted relay vehicle. The relay vehicle helps the two-way transmission but also acts as a potential eavesdropper. Each vehicle has a random velocity. By exploiting the random carrier frequency offsets (CFOs) caused by random motions, a secure double-differential two-way relay scheme is proposed. While achieving successful two-way transmission for the source vehicles, the proposed scheme guarantees a high decoding error floor at the untrusted relay vehicle. Average symbol error rate (SER) performance for the source vehicles and the untrusted relay vehicle is analyzed. Simulation results are provided to verify the proposed scheme.

Network-Coding Based Two-way Relay Communication Using Adaptive Modulation Sheme (적응형 변조 기법을 이용한 네트워크 부호화 기반 양방향 중계 통신)

  • Lee, Jin-Hee;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.5
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    • pp.147-151
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    • 2010
  • In this paper, we propose network-coding based two-way relay communication using adaptive modulation scheme for satisfying relay QoS(Quality of Service) according to channel environment between user and relay. Two-way relay communication is bidirectional cooperative communication that users exchange own signal with help of relay. Network-coding based two-way relay communication can achieve high throughput compared to conventional scheme through reducing time slots. we propose adaptive M-QAM modulation scheme in network-coding based two-way relay communication for satisfying QoS of relay. Simulation result shows that the proposed scheme satisfies goal QoS of system.

Outage Probability Analysis of Adaptive Two-Way Relay Cooperative Communication (적응형 양방향 중계기 협력 통신의 오수신 확률 분석)

  • Lee, Jin-Hee;Kong, Hyung-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.4
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    • pp.392-398
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    • 2010
  • In this paper, we proposed adaptive two-way relay cooperative communication considering the quality of the user-relay links, and derived outage probability. Network-coding based two-way relay communication can achieve more throughput since it can reduce transmission time compared conventional two-way relay communication. However, Network-coding based two-way relay communication assume that the relay can decode received signal correctly. If relay cannot decode the signal, it leads to error propagation at the relay. In this paper, we proposed adaptive two-way relay cooperative communication scheme. In proposed scheme, the user "A" transmits the signal to relay and another user "B". The relay operates adaptively depend on quality of user-relay links. Simulation result show that proposed scheme has better performance when the quality of the user-relay links are poor. Also it can get diversity order 2.

SER-Based Relay Selection for Two-Way Relaying with Physical Layer Network Coding

  • Li, Dandan;Xiong, Ke;Qiu, Zhengding;Du, Guanyao
    • ETRI Journal
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    • v.35 no.2
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    • pp.336-339
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    • 2013
  • To enhance the symbol error rate (SER) performance of the two-way relay channels with physical layer network coding, this letter proposes a relay selection scheme, in which the relay with the maximal minimum distance between different points in its constellation among all relays is selected to assist two-way transmissions. We give the closed-form expression of minimum distance for binary phase-shift keying and quadrature phase-shift keying. Additionally, we design a low-complexity method for higher-order modulations based on look-up tables. Simulation results show that the proposed scheme improves the SER performance for two-way relay networks.

Performance Analysis of Two-way Cooperative ARQ Protocol Using Network Coding (네트워크 부호화를 사용한 양방향 협력 ARQ 프로토콜의 성능 분석)

  • Byun, Il-Mu;Lee, Hyung-Yeol;Kim, Kwang-Soon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.10A
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    • pp.972-979
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    • 2008
  • Two-way relay channel is a bidirectional cooperative communication channel that two terminals communicate each other with the help of a relay. In the previous cooperative communication schemes, a relay uses two divided resources for bidirectional transmission. When a network coding is used at a relay, the relay can transmit bidirectional data to two terminals simultaneously using one resource only. Thus the throughput of this scheme is greater than that of the previous scheme. In this paper, we showa two-way cooperative ARQ protocol using network coding and the throughput of this protocol is analyzed using a state diagram.

Achievable Rate Region Bounds and Resource Allocation for Wireless Powered Two Way Relay Networks

  • Di, Xiaofei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.2
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    • pp.565-581
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    • 2019
  • This paper investigates the wireless powered two way relay network (WPTWRN), where two single-antenna users and one single-antenna relay firstly harvest energy from signals emitted by a multi-antenna power beacon (PB) and then two users exchange information with the help of the relay by using their harvested energies. In order to improve the energy transfer efficiency, energy beamforming at the PB is deployed. For such a network, to explore the performance limit of the presented WPTWRN, an optimization problem is formulated to obtain the achievable rate region bounds by jointly optimizing the time allocation and energy beamforming design. As the optimization problem is non-convex, it is first transformed to be a convex problem by using variable substitutions and semidefinite relaxation (SDR) and then solve it efficiently. It is proved that the proposed method achieves the global optimum. Simulation results show that the achievable rate region of the presented WPTWRN architecture outperforms that of wireless powered one way relay network architecture. Results also show that the relay location has significant impact on achievable rate region of the WPTWRN.

Outage Analysis and Optimization for Time Switching-based Two-Way Relaying with Energy Harvesting Relay Node

  • Du, Guanyao;Xiong, Ke;Zhang, Yu;Qiu, Zhengding
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.2
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    • pp.545-563
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    • 2015
  • Energy harvesting (EH) and network coding (NC) have emerged as two promising technologies for future wireless networks. In this paper, we combine them together in a single system and then present a time switching-based network coding relaying (TSNCR) protocol for the two-way relay system, where an energy constrained relay harvests energy from the transmitted radio frequency (RF) signals from two sources, and then helps the two-way relay information exchange between the two sources with the consumption of the harvested energy. To evaluate the system performance, we derive an explicit expression of the outage probability for the proposed TSNCR protocol. In order to explore the system performance limit, we formulate an optimization problem to minimize the system outage probability. Since the problem is non-convex and cannot be directly solved, we design a genetic algorithm (GA)-based optimization algorithm for it. Numerical results validate our theoretical analysis and show that in such an EH two-way relay system, if NC is applied, the system outage probability can be greatly decreased. Moreover, it is shown that the relay position greatly affects the system performance of TSNCR, where relatively worse outage performance is achieved when the relay is placed in the middle of the two sources. This is the first time to observe such a phenomena in EH two-way relay systems.

Resource Allocation Schemes for Legacy OFDMA Systems with Two-Way DF Relay (양방향 복호전달 릴레이를 사용하는 레거시 OFDMA 시스템에서의 자원 할당 기법)

  • Seo, Jongpil;Han, Chulhee;Park, Seongho;Chung, Jaehak
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.10
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    • pp.593-600
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    • 2014
  • OFDMA systems solves frequency selective fading problem and provides improved performance by optimal allocation of subcarriers and transmit power. Two-way relay systems provide improved spectral efficiency compared to that of the conventional half-duplex relay using bidirectional communications. In legacy OFDMA system such as WiBro, two-way DF relay utilization causes pilot re-assignment and impossibility of channel estimation and decoding at relay nodes by self-interference. In this paper, resource allocation schemes for legacy OFDMA systems with two-way DF relay are proposed. The proposed schemes allocate subcarriers considering destinations nodes which are connected to relay nodes as individual nodes which are directly connected to a base station. Subsequently, the proposed schemes compensate bandwidth loss due to orthogonal allocations by overlapped allocating unused subcarriers at other noes. Numerical simulations show that the proposed resource allocation schemes provide improved performance compared with orthogonal allocation.