• 한국컴퓨터정보학회논문지
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• 제21권3호
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• pp.25-32
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• 2016

Mobile Ad Hoc Networks(MANETs) consists of mobile nodes which communicate with each other without any centralized infrastructure. Message broadcasting by flooding for route discovery in MANET can result in high redundant retransmission, contention and collision of broadcasting packet, known as the broadcast storm problem collectively. The cross-layer design is adopted in this paper, which lets routing layer share the received signal strength information at MAC layer. Also this paper proposes a new probabilistic approach that dynamically adjusts the rebroadcasting probability of a node for routing request packets (RREQs) according to the received signal strength. The simulation results show that the proposed approach demonstrates better performance than blind flooding, fixed probabilistic broadcasting approaches.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.332-339
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• 2013

The network nodes in a tactical network moves continuously and due to the physical and electronic obstacles, the connections are not always available. Due to the frequent disconnections, it is hard to discover the path among the nodes in a DTN. According to PROPHET(Probabilistic Routing Protocol using History of Encounters and Transitivity), one of the most well-known DTN routing protocols, a DTN node determines whom to forward a packet according to the packet delivery probability. From the viewpoint of a node, the packet delivery probability of another node is degraded while the nodes are disconnected whereas it is improved when they encounter. In this paper, we enhance the algorithm estimating the packet probability by considering the encounter count as an additional parameter. Our algorithm prefers the node that encounters the destination more frequently in selecting the next hop toward the destination. We evaluated the performance of our algorithm by simulating military operations using a DTN-dedicated simulator. Through the simulations, we show that our proposed algorithm achieve higher packet delivery ratio with similar overhead compared with PROPHET.

• 대한전자공학회논문지
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• 제25권5호
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• pp.572-579
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• 1988

In this paper, a system of automatic placement and routing for gate array layout design is proposed. In the placement stage, the circuit is partitioned and using the concept of min-cut slicing, and each partitioned module is placed, so that the routing density over the entire chip be uniformized and the total wiring length be minimized. In the global routing stage, the concept of the probabilistic routing density is introduced to unify the wiring congestions in each channel. In the detailed routing stage, the multi-terminal nets are partitioned into the two-terminal nets. The ordered channel graph is proposed which implies the vertical and the horizontal constranint graphs simultaneously. And using the ordered channel graph, the proposed routing algorithm assigns the signal nets to the tracks. Also the proposed placement and routing algorithms are implimented on IBM/PC-AT to construct PC-level gate array layout system.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.649-657
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• 2013

DTN flooding based routing protocol replicate the message copy to increase the delivery like hood that overloads the network resources. The probabilistic routing protocols reduce replication cost by forwarding the message to a node that holds high predictability value to meet its destination. However, the network traffic converges to high probable nodes and produce congestion that triggers the drop of previously stored messages. In this paper, we have proposed a routing protocol called as Connection frequency Buffer Aware Routing Protocol (CFBARP) that uses an adaptive method to maintain the information about the available buffer space at the receiver before message transmission. Furthermore, a frequency based method has been employed to determine the connection recurrence among nodes. The proposed strategy has performed well in terms of reducing message drop, message relay while increases the delivery probability.

• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.329-336
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• 2012

For designing broadcast protocols in mobile ad hoc networks (MANETs), one of the important goals is to reduce the rebroadcast packets redundancy while reaching all the nodes in network. In this paper, we propose a probabilistic broadcasting mechanism based on selfishness and additional coverage in MANETs. Our approach dynamically adjusts the rebroadcast probability according to the extra covered area and number of neighbor nodes. By these two factors, mobile hosts can be classified into three groups: normal, low selfishness, and high selfishness groups. The nodes in the normal group forward packets for other nodes with high probability, whereas the nodes in the low selfishness group rebroadcast packets with low probability and the nodes in the high selfishness group do not rebroadcast packets. We compared our approach with simple flooding and the fixed probabilistic approach. The simulation results show that the proposed schemes can significantly reduce the number of retransmissions by up to 40% compared simple flooding and fixed probabilistic scheme without significant reduction in the network reachability and end-to-end packet delay.

• 한국멀티미디어학회논문지
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• 제19권5호
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• pp.910-917
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• 2016

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to the sink node to pass collected data. However, the communication distance of the sensor nodes at low cost and at low power is not long, it requires a data transfer through the multi-hop to transmit data to the sink node. In the existing cluster-based sensor network studies, cluster process and route selection process are performed separately in order to configure the routing path to the sink node. In this paper, in order to use the energy of the sensor nodes that have limited resources efficiently, a cluster-based multi-hop routing protocol which merges the clustering process and routing process is proposed. And the proposed method complements the problem of uneven cluster creation that may occur in probabilistic cluster methods and increases the energy efficiency of whole sensor nodes.

• 한국통신학회논문지
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• 제40권5호
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• pp.857-859
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• 2015

본 논문은 다중-홉 해양통신망의 종단간 경로 설정을 위한 ad-hoc on-demand vector (AODV) 기반의 flooding에서 발생하는 다중 복제 오버헤드를 줄이기 위해 제시된 지향성 라우팅 프로토콜을 다룬다. 확률 기하(stochastic geometry) 분석 기법을 이용하여 목표 라우팅 성공 확률과 선박국의 밀도에 따라 적응적으로 라우팅 오버헤드를 최소화하는 방식을 제안한다.

• 전기학회논문지
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• 제65권12호
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• pp.2218-2224
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• 2016

Opportunistic routing is designed for an environment where there is no stable end-to-end routing path between source node and destination node, and messages are forwarded via intermittent contacts between nodes and routed using a store-carry-forward mechanism. In this paper, we consider PRoPHET(Probabilistic Routing Protocol using History of Encounters and Transitivity) protocol as a base opportunistic routing protocol and propose an efficient context-aware opportunistic routing protocol by using the context information of delivery predictability and node type, e.g., pedestrian, car, and tram. In the proposed protocol, the node types of sending node and receiving node are checked. Then, if either sending node or receiving node is tram, messages are forwarded by comparing the delivery predictability of receiving node with predefined delivery predictability thresholds depending on the combination of sending node and receiving node types. Otherwise, messages are forwarded if the delivery predictability of receiving node is higher than that of sending node, as defined in PRoPHET protocol. Finally, we analyze the performance of the proposed protocol from the aspect of delivery ratio, overhead ratio, and delivery latency. Simulation results show that the proposed protocol has better delivery ratio, overhead ratio, and delivery latency than PRoPHET protocol in most of the considered simulation environments.

• 한국통신학회논문지
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• 제40권11호
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• pp.2205-2217
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• 2015

생체모방 라우팅 프로토콜은 동적 환경에서 집단 생명체가 분산 자율적인 방식으로 최적 경로를 찾아가는 원리를 이용하여 네트워크 토폴로지 변화에 따라 오버헤드를 줄이며, 라우팅 성능을 극대화하고, 경로 단절시 빠른 복구가 가능하다. 본 논문에서는 이동 애드혹 네트워크를 위한 생체모방 라우팅 프로토콜을 제안한다. 제안 방식은 추가적인 오버헤드 없이 라우팅 정보를 얻기 위하여 무선 매체의 엿듣기(overhearing) 기능을 사용한다. 엿듣기를 통해 출발지와 목적지 사이의 최단 경로 주변에 페로몬을 확산시키고, 확산된 페로몬을 기반으로 확률적 경로 탐색을 수행하여 출발지와 목적지 간 유용한 대체 경로를 확보한다. 이와 같은 방식으로 제안 프로토콜은 제어 오버헤드를 줄이면서 최신의 라우팅 정보를 획득할 수 있다. 시뮬레이션 결과 제안하는 생체모방 라우팅 프로토콜은 기존 AODV 및 AntHocNet 프로토콜 보다 우수한 라우팅 성능을 보여주면서 AntHocNet 보다 오버헤드를 크게 감소시킨다.

• Journal of Communications and Networks
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• 제6권4호
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• pp.331-342
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• 2004

We study the problem of controlling data overhead of mesh-based multicast ad hoc routing protocols by adaptively adding redundancy to the minimal data overhead multicast mesh as required by the network conditions. We show that the computation of the minimal data overhead multicast mesh is NP-complete, and we propose an heuristic approximation algorithm inspired on epidemic algorithms. In addition, we propose a mobility-aware and adaptive mesh construction algorithm based on a probabilistic path selection being able to adapt the reliability of the multicast mesh to the mobility of the network. Our simulation results show that the proposed approach, when implemented into ODMRP, is able to offer similar performance results and a lower average latency while reducing data overhead between 25 to 50% compared to the original ODMRP.