• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.116-119
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• 2016

무선 센서 망에서 모바일 싱크 그룹에게 데이터를 전송하기 위한 Mobile Geocasting에 관한 연구가 진행되었다. Mobile Geocasting에서, 싱크 그룹의 지역에 싱크들에게 데이터를 전송하기 위해 유니캐스팅과 플러딩의 두 가지 접근 방식이 있다. 에너지 효율성의 관점에서, 유니캐스팅은 분산된 적은 수의 분산된 싱크들에게 효율적인 전송 방식이고, 반면에 플러딩은 다수의 밀집된 싱크들에게 효율적인 전송 방식이다. 하지만, 이 두 가지 방식은 모두 너무 극단적으로 보수적인 방법이기 때문에, 그룹 지역 내에 싱크들이 전체적으로는 분산적이지만 부분적으로는 밀집하게 분포된 일반적인 상황들을 지원하기는 어렵다. 그러므로, 본 논문은 일반적인 분포를 가지는 이동 싱크 그룹을 효율적으로 지원하기 위한 유니캐스팅과 플러딩을 통합하는 하이브리드 방안을 제안한다. 제안 방안은 그룹 지역내에 분산된 싱크들을 위해서는 개별적 유니캐스팅과 밀집된 싱크들에게는 부분적 플러딩을 이용한다. 부분적 플러딩 지역을 도출하기 위해, 제안 방안은 하나의 수학적 모델을 제시한다. 시뮬레이션 결과는 제안 방안이 기존의 방안들보다 에너지 소비 관점에서 더 효율적임을 증명한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1050-1061
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• 2009

The Tactical Internet(TI) managed by Infantry Brigades is used for the purpose of sharing information of Command Control and Situation Awareness. When there are more than two destinations to transmit data in the TI system, a multicasting is utilized based on pre-defined multicast groups. However even in the case when a source node needs to send some messages like weathercast and attack alarm etc to only a part of Battalion or Brigades in a specific geographical region (destination region), the current TI multicasting protocol is designed to transmit the messages to the pre-defined group or all of the Battalion/Brigade nodes, resulting in inefficiency in terms of end-to-end delay and overhead. In this paper, we propose more efficient protocol for such cases, named as "Tactical Internet Geocasting (TIG)". The proposed scheme firstly checks whether the destination region belongs to one Battalion region or more than two Battalion regions using location information, and then performs a greedy forwarding from the source node to the destination region, followed by a local flooding inside of the destination region. With performance analysis and simulations using NS-2, TIG is compared to the current TI multicasting protocol (i.e., Simplified MDP) and the LBM (Location-based Multicast). The simulation results show that the proposed TIG is more efficient than both in terms of delay and network overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6A
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• pp.538-546
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• 2010

This paper presents an overview of position-based routing algorithms. We analyze performances of routing algorithms such as Hybrid Opportunistic Forwarding (HOF), Opportunistic multi-hop routing (ExOR), Location based Geocasting and Forwarding (LGF), and Greedy Forwarding in nearest with forward Progress (GFP) routing algorithms to find the best one in terms of packet error rate and throughput efficiency over effects of fading and noise variance in wireless networks. The analyses in closed form expressions are confirmed by the simulation results, which fully agree to analysis results. Additionally, the simulation results indicate significant differences among algorithms when varying the average SNR or the number of relays.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8A
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• pp.679-687
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• 2005

A mobile ad-hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. It is necessary to use bandwidth effectively because MANET has limited bandwidth. In this paper, we propose SMGS (source based multiple gateway selection routing protocol). In SMGS, each node estimates its expected life time (ELT) and if its ELT is larger than that of current gateway it becomes a candidate node. When a source node establishes a path, in each grid the candidate node will take the route request and be a gateway node for the each source node. The node that is expected to stay the longest time in the grid is selected so that we can reduce frequent gateway handoff, packet loss, and handoff delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6A
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• pp.617-625
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• 2011

In wireless sensor networks, data dissemination protocols have been proposed for mobile sink groups that are characterized by geographically staying closely and collective movement. They usually exploit flooding technology for mobility supporting and data delivery guarantee. However, it causes the excessive energy consumption of all sensor nodes in the group region due to data delivery participation. Moreover, the costs of the flooding would become higher in proportional to the group region. In this paper, we propose an energy efficient data dissemination scheme that resolves these problems. The virtual infrastructure called a 'pipe' is used as a rendezvous area. A source delivers data to the pipe, from which member sinks in the group retrieve it directly. Simulation results showed that this solution has better performance than existing protocols in terms of energy consumption as it reduces the number of regional flooding and eliminates unnecessary data flooding.