• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.2094-2114
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• 2022

Due to the wide application of fifth generation communication, wireless sensor networks have become an indispensable part in our daily life. In this paper, we analyze physical layer security for two-way relay with energy harvesting (EH), where power splitter is considered at relay. And two kinds of combined methods, i.e., selection combining (SC) and maximum ratio combining (MRC) schemes, are employed at eavesdropper. What's more, the closed-form expressions for security performance are derived. For comparison purposes, this security behaviors for orthogonal multiple access (OMA) networks are also investigated. To gain deeper insights, the end-to-end throughput and approximate derivations of secrecy outage probability (SOP) under the high signal-to-noise ratio (SNR) regime are studied. Practical Monte-Carlo simulative results verify the numerical analysis and indicate that: i) The secure performance of SC scheme is superior to MRC scheme because of being applied on eavesdropper; ii) The secure behaviors can be affected by various parameters like power allocation coefficients, transmission rate, etc; iii) In the low and medium SNR region, the security and channel capacity are higher for cooperative non-orthogonal multiple access (NOMA) systems in contrast with OMA systems; iv) The systematic throughput can be improved by changing the energy conversion efficiency and power splitting factor. The purpose of this study is to provide theoretical direction and design of secure communication.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.108-110
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• 2015

본 논문은 Delay Tolerant Networks(DTN)에서 이동노드의 속도, 방향과 같은 속성정보를 활용하여 이동노드의 상황에 따른 최적의 중계노드를 선정하는 기법을 제안한다. 중계노드의 이동성에 의하여 데이터 패킷을 전달함으로써 목적노드와 상이한 이동성의 중계노드가 선정되면, 전송 지연시간 및 패킷 손실이 자주 발생하였다. 따라서 본 논문에서는 전송 지연시간 및 패킷 손실이 증가하는 문제를 극복하기 위해, 이동노드의 속성정보를 활용하여 중계노드를 선정하는 기법을 제안한다. 제안하는 알고리즘은 서로 다른 이동노드가 접근하면 서로의 속도, 방향과 같은 속성정보를 교환한다. 또한 이동노드의 속성정보를 통해 각 이동노드의 상황을 인지하고 분석함으로써 목적노드에게 효율적으로 데이터를 전달 할 수 있는 중계노드를 선정하게 된다. 주어진 모의 실험결과 이동 노드의 속성정보를 활용하여 중계노드를 선정함으로써 패킷 전송률 측면에서 기존의 연구결과보다 향상된 결과를 보여주었다.

• 한국통신학회논문지
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• 제34권10A호
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• pp.752-759
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• 2009

본 논문에서는 간단히 한국통신학회의 논문작성법에 대하여 설명하고자 합니다. (스타일-요약본문)협력 다이버시티 기법은 다중경로 페이딩 환경을 효과적으로 극복할 수 있는 통신 기술이다. 이 기술을 에너지 제한된 무선 센서 네트워크에 적용하기 위해서는 무선 센서네트워크에서 가장 중요한 성능요소인 네트워크 수명을 고려한 릴레이 선택과 전력 할당 방법 등이 설계되어야 한다. 본 논문에서는 네트워크 수명을 최대화하기 위해 노드의 잔여전력을 고려한 새로운 다중 릴레이 선택 및 전력 할당 알고리즘을 제시하였다. 제시한 알고리즘은 2단계로 구분 되어 있다. 먼저 각 노드의 채널 상태를 고려하여 릴레이 후보노드를 선택 한 후 각 노드의 잔여전력을 고려하여 전력을 할당함으로써 전체 송신전력을 최소화함과 동시에 네트워크수명을 극대화 하도록 하였다. 본 논문에서 제시한 알고리즘은 기본적으로 AF(Amplify and Forward) 릴레이 모델을 바탕으로 하였으며 시뮬레이션을 통해 제안한 방식이 기존의 방식에 비해 더 높은 네트워크 수명을 가지는 것을 입증할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.50-67
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• 2015

The Cognitive Radio (CR) paradigm in tactical ad hoc networks is an important element of future military communications for network-centric warfare. This paper presents a novel Cognitive Link State Routing protocol for CR-based tactical ad hoc networks. The proposed scheme provides prompt and reliable routes for Primary User (PU) activity through procedures that incorporate two main functions: PU-aware power adaptation and channel switching. For the PU-aware power adaptation, closer multipoint relay nodes are selected to prevent network partition and ensure successful PU communication. The PU-aware channel switching is proactively conducted using control messages to switch to a new available channel based on a common channel list. Our simulation study based on the ns-3 simulator demonstrates that the proposed routing scheme delivers significantly improved performance in terms of average end-to-end delay, jitter, and packet delivery ratio.

• 한국정보처리학회논문지
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• 제6권11호
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• pp.3108-3115
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• 1999

Frame relay needs UPC function for the multiplexed logical connections to prevent malicious user traffic from incoming to network, to guarantee the QoS of conformed user traffic, and to protect the normal operation of network system. On the FR/ATM interworking in ATM networks, the UPC may be conducted either by cell-based ATM UPC or frame-based FR UPC. Frames come into and traverse ATm networks by segmentation to ATM cells. Of course, FR QoS should be guaranteed in spite of segmentation and reassembly in ATM networks. In this paper, we compared the QoS of cell-based ATM UPC and frame-based FR UPC in terms of analysis and simulation in case of ingress of excess traffic over negotiated traffic parameters at user-to-network interface. Also we studied frame-based UPC schemes including window-based FR UPC and frame-based VSA which is an ATM UPC algorithm recommended by ITU-T. We described introductions to frame relay including frame structure and FR/ATM interworking, FR traffic parameters and their relationship, comparison of FR QoS between frame-based FR UPC and cell-based ATM UPC, comparison of FR UPC schemes, necessities of egress traffic control, and conclusions.

• 한국정보통신학회논문지
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• 제17권6호
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• pp.1324-1329
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• 2013

본 논문에서는 WiMedia D-MAC 기술 기반 Wireless USB 프로토콜에서 분산적인 SoQ기반 Wireless USB Channel 자원 할당 방법의 성능을 분석하고, QoS 성능 향상을 위해 릴레이 통신 기술을 적용한 SoQ 릴레이 전송 프로토콜을 제안한다. 본 논문에서 제안하는 SoQ 릴레이 전송 프로토콜은 Satisfaction of QoS (SoQ) 알고리즘을 각 단말 디바이스 내 WiMedia D-MAC 계층에서 분산적으로 실행하고, 충돌대상 디바이스에게 예약된 QoS 자원을 유지할 수 있도록 Direct Link 뿐만 아니라 릴레이 노드를 경유하여 또 다른 Indirect Link 링크를 예약할 수 있는 자원 예약 프로토콜을 제안한다.

• 한국통신학회논문지
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• 제39C권8호
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• pp.696-707
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• 2014

본 논문에서는 UWB 기술 기반 무선 USB(WUSB) 프로토콜에서, 디바이스들의 이동성으로 인해 발생하는 Private Distributed Reservation Protocol (DRP) 예약 충돌 현상을 분석한다. 그리고 Private DRP 예약 충돌 시 발생하는 성능 저하를 감소시키기 위해 Private DRP 릴레이 통신 기술을 제안한다. 본 논문에서 제안하는 Private DRP 릴레이 통신 프로토콜은 충돌대상 디바이스에게 예약된 자원을 유지할 수 있도록 Direct Link 뿐만 아니라, Private DRP 예약 충돌 시 릴레이 노드를 경유하여 또 다른 Indirect Link 링크를 빠르게 예약할 수 있는 분산적인 자원 예약 프로토콜을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권6호
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• pp.1996-2013
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• 2015

This paper considers a scenario that more D2D users exist in the cell, they compete for cellular resources to increase their own data rates, which may cause transmission interference to cellular users (CU) and the unfairness of resource allocation. We design a resource allocation scheme for selfish D2D users assisted by cooperative relay technique which is used to further enhance the users' transmission rates, meanwhile guarantee the QoS requirement of the CUs. Two transmission modes are considered for D2D users: direct transmission mode and cooperative relay transmission mode, both of which reuses the cellular uplink frequency resources. To ensure the fairness of resource distribution, Nash bargaining theory is used to determine the transmission mode and solve the bandwidth allocation problem for D2D users choosing cooperative relay transmission mode, and coalition formation game theory is used to solve the uplink frequency sharing problem between D2D users and CUs through a new defined "Selfish order". Through theoretical analysis, we obtain the closed Nash bargaining solution under CUs' rate constraints, and prove the stability of the formatted coalition. Simulation results show that the proposed resource allocation approach achieves better performance on resource allocation fairness, with only little sacrifice on the system sum rates.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4483-4501
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• 2015

In this paper, we investigate a security transmission scheme at the physical layer for cooperative wireless relay networks in the presence of a passive eavesdropper. While the security scheme has been previously investigated with perfect channel state information(CSI) in the presence of a passive eavesdropper, this paper focuses on researching the robust cooperative relay beamforming mechanism for wireless relay networks which makes use of artificial noise (AN) to confuse the eavesdropper and increase its uncertainty about the source message. The transmit power used for AN is maximized to degrade the signal-to-interference-plus-noise-ratio (SINR) level at the eavesdropper, while satisfying the individual power constraint of each relay node and worst-case SINR constraint at the desired receiver under a bounded spherical region for the norm of the CSI error vector from the relays to the destination. Cooperative beamforming weight vector in the security scheme can be obtained by using S-Procedure and rank relaxation techniques. The benefit of the proposed scheme is showed in simulation results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5455-5475
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• 2016

In this article, we model the distributed relay assignment network as a many-to-one matching market with peer effects. We discuss two scenarios for throughput optimization of relay networks: the scenario of aggregate throughput optimization and the scenario of fairness performance optimization. For the first scenario, we propose a Mutual Benefit-based Deferred Acceptance (MBDA) algorithm to increase the aggregate network throughput. For the second scenario, instead of using the alternative matching scheme, a non-substitution matching algorithm (NSA) is designed to solve the fairness problem. The NSA improves the fairness performance. We prove that both two algorithms converge to a globally stable matching, and discuss the practical implementation. Simulation results show that the performance of MBDA algorithm outperforms existing schemes and is almost the same with the optimal solution in terms of aggregate throughput. Meanwhile, the proposed NSA improves fairness as the scale of the relay network expands.