• 한국멀티미디어학회논문지
• /
• 제2권2호
• /
• pp.184-194
• /
• 1999

본 논문은 양방향 스위치(bidirectional switchs)를 가진 다단계 상호연결망(MIN, Multistage Interconn nection Network)에서 중첩된 목적지 노드로 다중 메시지를 전송할 때 야기되는 스위치간의 블럭킹(blocking) 을 최소화하기 위한 알고리즘을 제시한다. U~MIN(Unicast MIN) 알고리즘[4]에 의해 제시되었던 다중 전송 트리는 하나의 소스 노드로부터 여러 개의 목적지 노드로 메시지를 전송하는 단순한 멀티캐스트를 수행하는 데 있어서는 매우 유용하지만, 다중 멀티캐스트를 수행하는데 있어서는 섬각한 채널 경쟁을 야기한다. 따라서 간접통신망에서 동시에 같은 목적지 노드를 가진 멀티캐스트가 발생했을 때 기존의 U-MIN 알고리즘에서 발생하는 심각한 채널 경쟁을 최소화하기 위한 방법으로 본 논문에서는 SPU-MIN(Source Partitioned U Unicast MIN) 알고리즘에 의한 새로운 멀티캐스트 트리를 제시한다 본 논문에서의 메시지 전송 방법은 웹흘 라우팅 기법에 기반한 반전(turnaround) 라우팅 알고리즘을 이용한다.

• 한국멀티미디어학회논문지
• /
• 제13권6호
• /
• pp.911-923
• /
• 2010

In wireless sensor networks (WSNs), cluster based data routing protocols have the advantages of reducing energy consumption and link maintenance cost. Unfortunately, most of clustering protocols have been designed for uniformly distributed sensor networks. However, some urgent situations do not allow thousands of sensor nodes being deployed uniformly. For example, air vehicles or balloons may take the responsibility for deploying sensor nodes hence leading a normally distributed topology. In order to improve energy efficiency in such sensor networks, in this paper, we propose a new cluster formation algorithm named DAEEC (Density Aware Energy-Efficient Clustering). In this algorithm, we define two kinds of clusters: Low Density (LD) clusters and High Density (HD) clusters. They are determined by the number of nodes participated in one cluster. During the data routing period, the HD clusters help the neighbor LD clusters to forward the sensed data to the central base station. Thus, DAEEC can distribute the energy dissipation evenly among all sensor nodes by considering the deployment density to improve network lifetime and average energy savings. Moreover, because the HD clusters are densely deployed they can work in a manner of our former algorithm EEVAR (Energy Efficient Variable Area Routing Protocol) to save energy. According to the performance analysis result, DAEEC outperforms the conventional data routing schemes in terms of energy consumption and network lifetime.

• Journal of Multimedia Information System
• /
• 제6권2호
• /
• pp.61-66
• /
• 2019

VANET (Vehicular Ad-hoc Network) is a mobile Ad-hoc Network which deals with the moving vehicles. VANET supports Intelligent Transport Systems (ITS) which is related to different modes of transport and traffic management techniques. VANETs enabled users to be informed and make them safer. VANET uses IEEE 802.11p standard wireless access protocol for communication. An important and necessary issue of VANET is to design routing protocols. In a network, communication takes place by the use of the routing protocols. There are mainly two types of communications used such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) in VANET. Vehicles can send and receive messages among them and also to and from infrastructure used. In this paper, AODV, DSR and DSDV are compared by analysing the results of simulation on various metrics such as average throughput, instant throughput, packet delivery ratio and residual energy. Findings indicates utilization of AODV and DSR is more applicable for these metrics as compared to DSDV. A network simulator (NS2) is used for simulation.

• 한국정보통신학회논문지
• /
• 제19권8호
• /
• pp.1917-1924
• /
• 2015

무선 센서 네트워크에서 멀리떨어진 목적노드까지 정보를 전달하기 위해서는 멀티홉전송을 통한 효율적인 라우팅기법이 필요로 된다. 멀티홉전송에 있어서 다중경로 라우팅기법을 사용하게 되면 특정 경로가 사용 불능 상태가 되거나 트래픽이 크게 증가하는 경우에도 다중경로를 활용한 안정적 데이터 전송이 가능하게 된다. 본 논문에서는 경로 전체에 대해 다중경로를 사용하는 기존 다중경로 라우팅 기법을 개선하여 일부 열악한 링크 구간만을 다중경로로 전송하는 부분 다중경로라우팅 방식을 제안함으로써 안전하고 빠른 데이터 전송을 보장함과 동시에 불필요하게 전송에 참여하는 노드의 수를 최소화함으로써 노드의 전력소모를 최소화하고 네트워크를 효율적으로 사용할 수 있도록 하였다.

• 한국멀티미디어학회논문지
• /
• 제17권2호
• /
• pp.191-199
• /
• 2014

도심에서의 VANET 통신을 위한 유니캐스팅 라우팅은 사용자 편의를 위해 매우 중요한 요소 기술이다. 유니캐스팅을 위해서는 적절한 경로로 패킷이 전달되어야 하는데 차량노드에서 활용 가능한 라우팅 관련정보에 한계가 있어 많은 문제가 발생한다. 특히 경로 재탐색 시 이미 실패한 경로를 다시 선택하고, 동일한 과정을 거쳐 또 다시 이전 실패 경로를 선택하게 되는 실패 경로 재 선택의 문제가 최종 패킷 전달 실패의 원인이 된다. 본 논문에서는 이러한 문제를 해결할 수 있는 VANET 유니캐스팅 라우팅의 경로 재탐색 기능강화 방안을 제안한다. 제안하는 경로 재탐색 기능은 이미 실패한 경로 정보를 패킷에 저장하여 경로 재탐색시 활용하도록 한다. 소스 라우팅을 기반으로 하는 기존의 VANET 라우팅 기법과의 성능 비교에서 제안한 방식의 우수성을 알 수 있다.

• Journal of Information Processing Systems
• /
• 제7권2호
• /
• pp.241-260
• /
• 2011

In earlier days, most of the data carried on communication networks was textual data requiring limited bandwidth. With the rise of multimedia and network technologies, the bandwidth requirements of data have increased considerably. If a network link at any time is not able to meet the minimum bandwidth requirement of data, data transmission at that path becomes difficult, which leads to network congestion. This causes delay in data transmission and might also lead to packet drops in the network. The retransmission of these lost packets would aggravate the situation and jam the network. In this paper, we aim at providing a solution to the problem of network congestion in mobile ad hoc networks [1, 2] by designing a protocol that performs routing intelligently and minimizes the delay in data transmission. Our Objective is to move the traffic away from the shortest path obtained by a suitable shortest path calculation algorithm to a less congested path so as to minimize the number of packet drops during data transmission and to avoid unnecessary delay. For this we have proposed a protocol named as Congestion Aware Selection Of Path With Efficient Routing (CASPER). Here, a router runs the shortest path algorithm after pruning those links that violate a given set of constraints. The proposed protocol has been compared with two link state protocols namely, OSPF [3, 4] and OLSR [5, 6, 7, 8].The results achieved show that our protocol performs better in terms of network throughput and transmission delay in case of bulky data transmission.

• 한국인터넷방송통신학회논문지
• /
• 제13권6호
• /
• pp.203-210
• /
• 2013

무선 애드혹 네트워크에서는 제한된 대역폭, 간섭, 높은 패킷 에러율로 인하여 영상과 같은 고속 데이터 전송 시 높은 전송 품질을 제공하기 어렵다. 본 논문에서는 이러한 제약을 극복하고 고품질의 고속 멀티미디어 데이터 전송을 제공하기 위하여 패킷전송성공률 기반의 종단간 경로 품질과 각 중계노드에서의 잔여 대역폭 예측을 이용하는 PBBR (Path-Quality and Bandwidth-Estimation Based Routing) 프로토콜을 제안한다. 제안된 프로토콜의 성능을 검증하기 위하여 NS2를 이용한 시뮬레이션이 수행되었으며, 시뮬레이션 결과는 제안되는 프로토콜이 기존의 라우팅 프로토콜에 비해 높은 Throughput을 획득할 수 있음을 보인다.

• 한국정보처리학회논문지
• /
• 제6권11S호
• /
• pp.3229-3242
• /
• 1999

At recent, the Internet is evolving into the directions which is capable of incorporating stream-type services such as voice and video services due to the remarkable growth of WWW service and the development of new multimedia application services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS-based routing algorithm in order to allow flexible routing by the Internet user's QoS demand and to be applied into wide area networks. In this paper, we presented new routing algorithms for next generation Internet services and made performance evaluations. The proposed algorithms allow the routing by the user's QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of next Generation Internet Services.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
• /
• pp.139-144
• /
• 2003

Mobile Node has to maintain communication as they move form place to place, so it doesn't guarantee Quality of Service(QoS). Fast Handoff is important to provide multimedia and real-time applications services in mobile, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to quarantee QoS as a main issue in mobile IP research area. Next generation Mobile IPv6 resolve this problem somewhat, triangle problem for first packet and handoff delay still remain. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-Based routing. After modeling of suggested method and existing handoff method, simulations are carried out with NS-2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권4호
• /
• pp.741-762
• /
• 2011

Recently, multicast routing protocols become increasingly important aspect in Mobile Ad hoc Networks (MANETs), as they effectively manage group communications. Meanwhile, multimedia and real-time applications are becoming essential need for users of MANET. Thus it is necessary to design efficient and effective Quality of Service (QoS) multicast routing strategies. In this paper, we address the scalability problem of multicast routing protocols to support QoS over MANETs. In particular, we introduce a Position-Based QoS Multicast Routing Protocol (PBQMRP). Basically, the protocol based on dividing the network area into virtual hexagonal cells. Then, the location information is exploited to perform efficient and scalable route discovery. In comparison with other existing QoS multicast routing protocols, PBQMRP incurs less control packets by eliminating network flooding behavior. Through simulation, the efficiency and scalability of PBQMRP are evaluated and compared with the well-known On-Demand Multicast Routing Protocol (ODMRP). Simulation results justify that our protocol has better performance, less control overhead and higher scalability.