• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권5호
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• pp.1354-1372
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• 2012

Route establishment in Mobile Ad Hoc Network (MANET) is the key mechanism to a successful connection between a pair of source and destination nodes. An efficient routing protocol constructs routing path with minimal time, less routing overhead and capable of utilizing all possible link connectivity. In general, most on-demand MANET routing protocols operates over symmetrical and bidirectional routing path, which is infeasible due to the inherent heterogeneous properties of wireless devices. Simulation results show that the presence of unidirectional links on a network severely affect the performance of a routing protocol. In this paper, a robust protocol independent scheme is proposed, which enable immediate rediscovery of alternative route for a path blocked by a unidirectional link. The proposed scheme is efficient; route rediscovery is locally computed, which results in significant minimization of multiple route packets flooding. Nodes may exploit route information of immediate neighbors using the local reply broadcast technique, which then redirect the control packets around the unidirectional links, therefore maintaining the end-to-end bidirectional connection. The proposed scheme along with Ad Hoc On-demand Distance Vector (AODV) and AODV-Blacklist routing protocol is investigated over three types of mobility models. Simulation results show that the proposed scheme is extremely reliable under poor network conditions and the route connectivity can be improved by as much as 75%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4451-4466
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• 2014

We present joint radio selection and relay scheme that delivers data from a source to a sink in heterogeneous stationary sensor networks consisting of various radio interfaces. The proposed scheme finds the optimal relay nodes and their corresponding radio interfaces that minimize energy consumption throughout the network while satisfying the end-to-end packet deadline requirement. We formulate the problem of routing through radio interface selection into binary integer programs, and obtain the optimal solution by solving with an optimization solver. We examine a trade-off relationship between energy consumption and packet delay based on network level simulations. We show that given the end-to-end deadline requirement, our routing algorithm finds the most energy-efficient routing path and radio interface across mesh hops. We demonstrate that the proposed routing scheme exploits the given packet delivery time to turn into network benefit of reducing energy consumption compared to routing based on single radio interface.

• 대한임베디드공학회논문지
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• 제14권4호
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• pp.177-186
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• 2019

In wireless sensor networks, the transmission success ratio would be decreased when the scale of the WSNs increased. To defeat this problem, we propose a multipath routing based on opportunistic routing for improving end-to-end reliability in large-scale wireless sensor networks. The proposed scheme exploits the advantages of existing opportunistic routing and achieves high end-to-end success ratio by branching like a multipath routing through local decision without information of the whole network. As a result of the simulation result, the proposed scheme shows a similar or higher end-to-end transmission success ratio and less energy consumption rather than the existing scheme.

• 한국콘텐츠학회논문지
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• 제14권11호
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• pp.16-27
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• 2014

본 논문에서는 모바일 애드혹 네트워크에서 라우팅 비용 감소를 위해 위치 정보를 이용한 효율적인 그리드 기반 라우팅 기법을 제안한다. 제안하는 기법은 헤더를 두지 않기 때문에 헤더 관리 비용이 감소하며 모든 노드가 메시지를 전송할 수 있다. 중간 노드들은 노드와 그리드간의 위치 관계에 기초하여 메시지를 중계하는 다음 홉을 결정한다. 각 그리드 영역의 좌표와 이웃 노드의 정보를 활용하여 노드의 방향성을 고려한 라우팅 경로 탐색을 한다. 또한, 노드들 사이의 연결성을 고려하여 라우팅 경로를 유지한다. 제안된 라우팅 기법의 우수성을 보이기 위해 성능평가를 통해 기존의 그리드 기반 라우팅 기법과 메시지 오버헤드, 전달 성공률을 비교한다.

• 정보처리학회논문지C
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• 제9C권1호
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• pp.135-140
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• 2002

효율적인 QoS 라우팅을 위하여 각각의 요구에 대한 제한조건을 충족시키는 것은 물론, 테 네트워크 자원의 최적화에 대해서도 고려해야할 필요가 있다. 본 논문에서는 QoS 라우팅의 on-demand 방식과 precomputation 방식의 경로계산에서 자원 비용 산정 방식을 제안하여 전체 네트워크 자원의 퇴적 사용과 네트워크 자원의 부하 균등을 가능하게 하였다. 또한 도메인으로 분할된 대규모 네트워크의 QoS 라우팅에서 transit traffic을 위한 경로를 precomputation 방식으로 설정하고, 이들 경로들의 예약 가능성을 높이기 위해 자원 예약 측면에서 가장 좋은 K개의 경로들을 부하균등을 고려하여 선정하는 방안을 제안하였다. 그리고 동일한 자원 비용 산정 방식을 transit traffic과 intra traffic에 모두 적용하여 도메인간 라우팅(inter-domain routing)과 도메인내 라우팅(inter-domain routing)을 무리 없이 연계하면서 transit traffic을 우선으로 하는 방식을 제안하였다. 귿으로 본 논문에서 제안된 비용 산정 방식은 기존의 QoS 라우팅 알고리즘 자체를 변형시키지 않으면서, 그들의 비용 요소만을 대체하여 쉽게 사용되어질 수 있는 장점이 있다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2008년도 추계 공동 국제학술대회
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• pp.507-511
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• 2008

Supporting energy efficiency and load balancing in wireless sensor network is the most important issue in devising the hierarchical routing protocols. Recently, the dual layered clustering scheme with GPS was proposed for the supporting of load balancing for cluster heads but there would be many collided messages in the overlapped area between two layers. Thereby, the purpose of this paper is to reduce the collision rate in the overlapped layer by concisely distinguish them with the same number of nodes in them. For the layer partition, this paper uses an equation $x^2+ y^2{\le}(\frac{R}{\sqrt{2\pi}})^2$ to distinguish layers. By using it, the scheme could efficiently distinguish two layers and gets the balanced number of elements in them. Therefore, the proposed routing scheme could prolong the overall network life cycle about 10% compared to the previous two layered clustering scheme.

• 전자공학회논문지S
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• 제34S권2호
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• pp.11-20
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• 1997

It is a recent trend that mobile communications and PCS are intergrated into the broadband network. Broadband mutlimedia traffic will be transported over the integrated network. In this paper, we propose a connection re-routing method for fast inter-switch hadoffs and dynamic resurce reservation scheme, which is based on the proposed re-routing method, for the ATM-based personal communications network. To reduce the delay for re-routing method, for the ATM-based personal communications network. To reduce the delay for re-routing, the proposed re-routing method is to reserve VPI/VCIs for possible inter-swich handoff calls in advance. Our reservation scheme is to statistically reserve the fixed resources for possible inter-switch handoff calls, according to the QoS of the handoff calls. The simmulation reslts show that our proposed scheme satisfies the required QoS of handoff calls and keep the dropping probability of handoff calls lower than other schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2534-2553
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• 2018

Source routing is the routing scheme that arranges the whole path from source to target at the origin node that may suit the requirements from the upper layer applications' perspective. The centralized control in SDN (Software-Defined Networking) networks enables the awareness of the global topology at the controller. Therefore, augmented source routing schemes can be designed to achieve various purposes. This paper proposes a source routing scheme that conducts the top-K QoS-aware paths discovery in SDN. First, the novel non-invasive QoS over LLDP scheme is designed to collect QoS information based on LLDP in a piggyback fashion. Then, variations of the KSP (K Shortest Paths) algorithm are derived to find the unconstrained/constrained top-K ranked paths with regard to individual/overall path costs, reflecting the Quality of Service. The experiment results show that the proposed scheme can efficiently collect the QoS information and find the top-K paths. Also, the performance of our scheme is applicable in QoS-sensitive application scenarios compared with previous works.

• Journal of Communications and Networks
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• 제11권4호
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• pp.327-336
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• 2009

Geographic routing has been considered as an attractive approach in wireless sensor networks, since it routes data packets by using location information rather than global topology information. In geographic routing schemes, packets are usually sent along the boundary of a hole by face routing to detour the hole. As result, all data flows which need to detour the hole are concentrated on the boundary of the hole. This hole detour scheme results in much more energy consumption for nodes at the hole boundary, and the energy exhaustion of hole boundary nodes enlarges the holes. This is referred to as a hole diffusion problem. The perimeter mode may also lead to data collisions on the hole boundary nodes if multiple data flows need to bypass a hole simultaneously. In this paper, we propose a hole modeling and detour scheme for geographic routing in wire-less sensor networks. Our hole modeling and detour scheme can efficiently prevent hole diffusion, avoid the local minimum problem faced by geographic routing protocols, and reduce data collisions on the hole boundary nodes. Simulation results show that the proposed scheme is superior to the other protocols in terms of control overhead, average delivery delay and energy consumption.

• 정보처리학회논문지C
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• 제9C권5호
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• pp.671-678
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• 2002

본 논문에서는 대규모 네트워크에서의 부하분산을 고려한 계층적 도메인간 QoS 라우팅을 제안하였다. 이를 위해 계층적 라우팅에서의 비용 산정 방식을 선계산 방식의 경로계산에서 제안하였고 선계산된 다중경로들 중에서 경로를 선택하는 방안을 제안하였다. 제안한 비용산정 방식은 도메인으로 분할된 대규모 네트워크의 QoS 라우팅에서 선계산 방식으로 경로를 설정하고, 이들 경로들의 예약 가능성을 높이기 위해 자원 예약 측면에서 가장 좋은 K개의 경로들을 부하분산을 고려하여 계산한다. 또한 이러한 다중 경로들 중에서 비용산정에 근거한 경로선택확률에 따라 경로를 선택하는 방안을 제안하였다. 그리고 제안한 QoS 라우팅 방식을 transit traffic과 intra traffic에 모두 적용하여 도메인간 라우팅과 도메인내 라우팅을 무리 없이 연계하면서 transit traffic을 우선으로 하는 방식을 제안하였다. 따라서 본 논문에서 제안한 부하분산 QoS 라우팅은 전체 네트워크 자원의 최적사용 뿐만 아니라 자원의 부하 분산을 가능하게 할 것으로 기대된다.