• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.451-466
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• 2003

Untethered nodes in mobile ad-hoc networks strongly depend on the efficient use of their batteries. In this paper, we propose a new metric, the drain rate, to forecast the lifetime of nodes according to current traffic conditions. This metric is combined with the value of the remaining battery capacity to determine which nodes can be part of an active route. We describe new route selection mechanisms for MANET routing protocols, which we call the Minimum Drain Rate (MDR) and the Conditional Minimum Drain Rate (CMDR). MDR extends nodal battery life and the duration of paths, while CMDR also minimizes the total transmission power consumed per packet. Using the ns-2 simulator and the dynamic source routing (DSR) protocol, we compare MDR and CMDR against prior proposals for power-aware routing and show that using the drain rate for power-aware route selection offers superior performance results.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.4
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• pp.469-475
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• 2009

TMMR(Tactical Multiband Multirole Radio) is one of the important equipments for TICN which is our next military tactical communication system and it supplies to the distribution of traffic of C2(Command & Control) and SA(Situation Awareness) for unit of Brigade and below. In this paper, we define the tactical needs of military communication, and evaluate MANET(Mobile Ad-hoc Network) protocol for the future digital battle-field through performance comparison with a network simulator.

• Journal of the Korea Society for Simulation
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• v.13 no.4
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• pp.55-69
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• 2004

In MANET(Mobile Ad-hoc Network), unlike in wired networks, a path configuration should be in advance of data transmission along a routing path. Frequent movement of mobile nodes, however, makes it difficult to maintain the configured path and requires re-configuration of the path very often. It may also leads to serious problems such as deterioration of QoS in mobile ad-hoc networks. In this paper, we proposed a Reactive Routing Keyword (RRK) routing procedure to solve those problems. Firstly, we noticed it is possible in RRK routing to assign multiple routing paths to the destination node. We applied this feature into active networks and SNMP information based routing by storing unique keywords in cache of mobile nodes corresponding to present and candidate routings in a path configuration procedure. It was shown that the deterioration of QoS which may observed in Dynamic Source Routing(DSR) protocol was greatly mitigated by using the proposed routing technique.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.87-94
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• 2007

In mobile ad hoc networks the most popular on demand routing protocols are the Dynamic Source Routing (DSR) protocol and the Ad hoc On demand Distance Vector (AODV) routing protocol. These and other representative standard routing protocols are designed to find and maintain only a single path. Whenever there is a link break on the active route, source node has to invoke a route discovery process from the beginning and it causes a lot of overhead. Multipath routing protocols, which can alleviate these problems by establishing multiple alternative paths between a source and a destination, are widely studied. In this paper we propose a node disjoint multipath discovery technique based on AODV local route discovery. This technique can find and build completely separated node disjoint multi paths from a source to a destination as many as possible. It will make routing more robust and stable.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.31-33
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• 2004

We suggest an enhanced automatic route shortening method for dynamic source routing (DSR) protocol. DSR is a request / response based protocol which has low routing overhead owing to node movement. The original automatic route shortening is performed on the only nodes that belong to the source route of packets. On the contrary, our suggested method allows all neighbor nodes hearing the packet to participate in automatic route shortening. It makes all possible route shortenings be performed. So we maintain maximal short routes of ongoing data connections. Simulation results show that our method pays small extra overhead for ARS, but increases the ratio of packet transmissions and ARS' are performed from 2 to 5 times as much as original ARS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.277-280
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• 2009

Mobile Ad-hoc Network(MANET) could provide the reliable monitoring and control of a variety of environments for remote place. Mobility of MANET would require the topology change frequently compared with a static network. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. In this paper, we propose a new method that the CACH(Context-aware Clustering Hierarchy) algorithm, a hybrid and clustering-based protocol that could analyze the link cost from a source node to a destination node. The proposed analysis could help in defining the optimum depth of hierarchy architecture CACH utilize. The proposed CACH could use localized condition to enable adaptation and robustness for dynamic network topology protocol and this provide that our hierarchy to be resilient.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.469-471
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• 2003

본 논문에서는 이동 애드­혹 네트워크(mobile ad­hoc networks)의 대표적인 경로구축 방법인 DSR(dynamic source routing)을 확장한 R­DSR(robust DSR)을 제안한다. 제안된 R­DSR에서는 기존의 단일 경로 상의 2­흡 간격의 모든 노드들이 대체 노드를 경유하여 복수 개의 라우팅 경로를 유지하도록 구성되기 때문에, 경로 상의 일부 노드들이 이동하더라도 경로가 유지될 확률이 높아 메시지 전달률이 향상된다. 수학적 분석을 통하여 관련 연구 중 가장 우수한 것으로 알려진 Das의 다중경로 프로토콜보다 더 높은 라우팅 경로 유지 확률을 나타냄을 보였다. 아울러, 대체경로의 위상적 특성에 의해 빠른 대체경로로의 복구도 가능하다는 결론을 얻었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1034-1042
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• 2008

It is very hard, but important to sustain path stability for a reliable communication in mobile ad hoc networks. We propose a novel source routing protocol that establishes a group path with virtual multiple paths to enable a robust communication. The entire mobile nodes form a disjoint set of clusters: Each has its clusterhead as a cluster leader and a unique cluster label to identify itself from other clusters. A group path is a sequence of cluster labels instead of nodes and the nodes with the same label collaborate to deliver packets to a node with next label on the group path. We prove by resorting to simulation that our proposed protocol outperforms the existing key routing protocols, even for a network with a high node mobility and a high traffic.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.475-482
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• 2007

Mobile nodes in ad-hoc wireless networks play roles of router as well as host. Movement of nodes causes network topology changes, which make existing routing information be modified. Therefore many routing protocols for ad-hoc networks were suggested in the literature. In this paper, we suggest an enhanced automatic route shortening method for dynamic source routing(DSR) protocol. DSR is a request/response based protocol which has low routing overhead owing to node movement. The current automatic route shortening is performed on the only nodes which belong to the source route of packets. On the contrary, our suggested method allows all neighbor nodes hearing the packet to participate in automatic route shortening. It makes all possible route shortenings be performed. So we maintain maximal shortened routes of ongoing data connections. Simulation results with ns2 show that our method pays small extra protocol overhead for ARS, but increases the ratio of successful packet transmissions and the number of ARSs performed in our mechanism is from 2 to 5 times higher than in original ARS mechanism and therefore it will improve the network-wide energy consumption in wireless ad-hoc networks.

• Journal of Communications and Networks
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• v.5 no.3
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• pp.266-274
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• 2003

One of the major issues in current on-demand routing protocols for ad hoc networks is the high resource consumed by route discovery traffic. In these protocols, flooding is typically used by the source to broadcast a route request (RREQ) packet in search of a route to the destination. Such network-wide flooding potentially disturbs many nodes unnecessarily by querying more nodes than is actually necessary, leading to rapid exhaustion of valuable network resources such as wireless bandwidth and battery power. In this paper, a simple optimization technique for efficient route discovery is proposed. The technique proposed herein is location-based and can be used in conjunction with the existing Location-Aided Routing (LAR) scheme to further reduce the route discovery overhead. A unique feature of our technique not found in LAR and most other protocols is the selective use of unicast instead of broadcast for route request/query transmission made possible by a novel reuse of routing and location information. We refer to this new optimization as the UNIQUE (UNIcast QUEry) technique. This paper studies the efficacy of UNIQUE by applying it to the route discovery of the Dynamic Source Routing (DSR) protocol. In addition, a comparative study is made with a DSR protocol optimized with only LAR. The results show that UNIQUE could further reduce the overall routing overhead by as much as 58% under highly mobile conditions. With less congestion caused by routing traffic, the data packet delivery performance also improves in terms of end-to-end delay and the number of data packets successfully delivered to their destinations.