• 한국통신학회논문지
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• 제33권10A호
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• pp.972-979
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• 2008

양방향 중계 채널 (two-way relay channel)은 2개의 단말이 중계기 (relay)의 도움을 받아 양방향의 정보를 주고 받는 협력 통신 (cooperative communication) 채널이다. 기존의 협력 통신에서는 중계기가 시간 또는 주파수 자원을 나누어 양방향으로 신호를 송신하지만, 네트워크 부호화 (network coding)를 사용한 양방향 중계 채널에서는 중계기가 동일 자원을 사용하여 두 단말로 신호를 동시에 송신하므로 기존 기법보다 높은 통신용량을 얻을 수 있다. 본 논문에서는 ARQ환경에서 네트워크 부호화를 사용한 헙력통신 프로토콜을 보이고, 이를 스테이트 다이어그램 (state diagram) 을 이용하여 성능을 분석하였다.

• Journal of Communications and Networks
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• 제10권4호
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• pp.422-429
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• 2008

Mobile peer-to-peer (P2P) systems have recently got in the limelight of the research community that is striving to build efficient and effective mobile content addressable networks. Along this line of research, we propose a new peer-to-peer file sharing protocol suited to mobile ad hoc networks (MANET). The main ingredients of our protocol are network coding and mobility assisted data propagation, i.e., single-hop communication. We argue that network coding in combination with single-hop communication allows P2P file sharing systems in MANET to operate in a more efficient manner and helps the systems to deal with typical MANET issues such as dynamic topology and intermittent connectivity as well as various other issues that have been disregarded in previous MANET P2P researches such as addressing, node/user density, non-cooperativeness, and unreliable channel. Via simulation, we show that our P2P protocol based on network coding and single-hop communication allows shorter file downloading delays compared to an existing MANET P2P protocol.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2012년도 한국컴퓨터종합학술대회논문집 Vol.39 No.1(D)
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• pp.366-368
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• 2012

Network Coding approach to IP tracback was proposed by Sattari et al. [5] in order to reduce number of packets required to trace the source of a single attack scenario. In this paper, we analysis and point out limitations and problems of their proof for benefit of network coding to IP traceback.

• 전기학회논문지P
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• 제64권4호
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.

• Journal of Communications and Networks
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• 제10권4호
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• pp.403-411
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• 2008

Energy consumption has been mostly neglected in network coding (NC) research so far. This work investigates several different properties of NC that influence the energy consumption and thus are important when designing NC systems for battery-driven devices. Different approaches to the necessary implementation of coding operations and Galois fields arithmetic are considered and complexity expressions for coding operations are provided. We also benchmark our own mobile phone implementation on a Nokia N95 under different settings. Several NC strategies are described and compared, furthermore expressions for transmission times are developed. It is also shown that the use of NC introduces a trade off between reduction in transmission time and increase in energy consumption.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(D)
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• pp.13-15
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• 2011

현재 무선 통신을 이용한 IPTV서비스에 대한 요구가 지속적으로 증가 되고 있다. 따라서 제한된 자원을 다수의 사용자들에게 효율적으로 전송하기 위한 기술이 개발되어야 한다. 본 논문에서 우리는 무선 IPTV의 VOD 시스템 성능 향상을 위해 효율적인 Batching 기법과 채널을 효과적으로 사용하기 위하여 Network coding을 활용한 기법을 제안한다. 제안된 기법은 채널을 효과적으로 사용하기 위하여 Network coding을 활용하였다. 현재의 Batching 기법은 다수의 채널을 사용하는 반면에 제안된 기법은 한 개의 채널에서 2개 이상의 세그먼트를 전송함으로써 얻어지는 채널사용의 효율성을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.686-710
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• 2019

This work proposes a model to solve the problem of Network Coding over a one-session multicast network. The model is based on a system of restrictions that defines the packet flows received in the sink nodes as functions of the outgoing flows from the source node. A multicast network graph is used to derive a directed labeled line graph (DLLG). The successive powers of the DLLG adjacency matrix to the convergence in the null matrix permits the construction of the jump matrix Source-Sinks. In its reduced form, this shows the dependency of the incoming flows in the sink nodes as a function of the outgoing flows in the source node. The emerging packets for each outgoing link from the source node are marked with a tag that is a linear combination of variables that corresponds to powers of two. Restrictions are built based on the dependence of the outgoing and incoming flows and the packet tags as variables. The linear independence of the incoming flows to the sink nodes is mandatory. The method is novel because the solution is independent of the Galois field size where the packet contents are defined.

• ETRI Journal
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• 제37권2호
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• pp.380-386
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• 2015

Guaranteeing quality of service over a multihop wireless network is difficult because end-to-end (ETE) delay is accumulated at each hop in a multihop flow. Recently, research has been conducted on network coding (NC) schemes as an alternative mechanism to significantly increase the utilization of valuable resources in multihop wireless networks. This paper proposes a new section-based joint NC and scheduling scheme that can reduce ETE delay and enhance resource efficiency in a multihop wireless network. Next, this paper derives the average ETE delay of the proposed scheme and simulates a TDMA network where the proposed scheme is deployed. Finally, this paper compares the performance of the proposed scheme with that of the conventional sequential scheduling scheme. From the performance analysis and simulation results, the proposed scheme gives more delay-and energy-efficient slot assignments even if the NC operation is applied, resulting in a use of fewer network resources and a reduction in ETE delay.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권3호
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• pp.446-458
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• 2013

Recently, energy-efficient cellular transmission has received considerable research attention to improve the energy efficiency of wireless communication. In this paper, we consider a cellular network consisting of one base station (BS) and multiple user terminals and explore the network coding for enhancing the energy efficiency of cellular downlink transmission from BS to users. We propose the network coded cellular transmission scheme and conduct its energy consumption analysis with target outage probability and data rate requirements in Rayleigh fading environments. Then, the energy efficiency in Bits-per-Joule is further defined and analyzed to evaluate the number of bits delivered per Joule of energy cost. Numerical results show that the network coded cellular transmission significantly outperforms the traditional cellular transmission in terms of energy efficiency, implying that given a Joule of energy cost, the network coded cellular transmission scheme can deliver more bits than the traditional cellular transmission.

• 한국산업정보학회논문지
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• 제29권5호
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• pp.1-9
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• 2024

다양한 형태의 차세대 무선 네트워크가 출현되면서 네트워크 노드에서 기존의 저장 및 전달(store and forward) 방식만으로는 네트워크 용량을 효율적으로 활용하지 못하는 한계가 있었다. 이러한 한계를 극복하기 위해 디코딩 및 전달(decode and forward) 방식의 다양한 네트워크 코딩 기술이 제안되었지만 중계할 노드 간의 비대칭 패킷 길이를 갖는 트래픽 환경에 초점이 맞추어져 있어 중계할 노드 간에 적용된 변조 및 코딩 스킴(modulation and coding scheme)이 상이할 경우 적용이 제한적이었다. 본 논문은 무선 네트워크 용량의 효율적 활용을 위해 동시에 양방향으로 상호중계하는 디코딩 및 전달 기술을 사용하면서, 개별 노드 간의 전송할 데이터와 상이한 무선채널 상태를 반영한 비대칭 변조 및 코딩 스킴의 트래픽을 양방향 상호중계하는 동시에 높은 주파수 효율성을 지원하는 중계 네트워크 코딩 방식을 제안한다. 또한 본 제안 방식을 통해 중계기에서 협력통신이 가능함을 보이고 통신 거리가 증대하는 효과를 살펴본다. 이후 컴퓨터 시뮬레이션을 통해서 비대칭 정보길이를 갖는 각 소스노드에서, 본 기술의 네트워크 코딩에 따른 성능 이득을 검증한다. 본 제안 기술은 소스노드 간 직접링크로 송수신이 가능한 이동노드 환경에서도 네트워크 코딩을 따르는 증가성 리던던시(incremental redundancy) 방식 수용으로 추가적인 비트 오류율에 대한 성능 이득이 있음을 보인다.