• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1415-1420
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• 2003

The mobile radio networks can be divided into networks that has the base station or the infrastructures like AP(Access Point) and Ad Hoc network that hasn't any infrastructures. As there aren't any fixed infrastructures in Ad Hoc Networks, mobile nodes should transmit the data oかy among mobile nodes themselves. To supplement these weakpoints of the two networks, many studies about Ad Hon based on the 802.11 are in progress. In this thesis, we try to propose the efficiency of the suggested protocols by comparing and analyzing power saving protocols according to the Beacon intervals in multi hop Ad Hoc Networks based on IEEE 802.11.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.141-144
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• 2003

The mobile radio networks can be divided into networks that has the base station or the infrastructures like AP(Access Point) and Ad Hoc network that hasn't any infrastructures. As there aren't any fixed infrastructures in Ad Hoc Networks, mobile nodes should transmit the data only among mobile nodes themselves. To supplement these weakpoints of the two networks, many studies about Ad Hocs based on the 802.11 are in progress. In this thesis, we try to propose the efficiency of the suggested protocols by comparing and analyzing power saving protocols according to the Beacon intervals in multi hop Ad Hoc Networks based on IEEE 802.11.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.33-44
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• 2008

Multipath routing protocols with load balance, fault tolerance, aggregated bandwidth in Ad-hoc Networks provide improved throughput and reliable route as compared with singlepath routing protocols. However, multipath routing protocols have not been explored thoroughly in the domain of overhead in Ad-hoc Networks. In this paper, we analyze and compare on-demand singlepath and multipath routing with IEEE 802.11 DCF in terms of Routing overhead and MAC overhead. The results reveals that in comparison with singlepath routing protocol, multipath routing mechanism creates more overheads but provides better performance in congestion and capacity provided that the route length is within a certain upper bound which is derivable. The analytical results are further confirmed by simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.31-33
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• 2005

이동 ad-hoc 네트워크는 기반 망의 도움 없이 모바일 노드들로만 구성되어진 임시적인 네트워크이다. ad-hoc 네트워크를 구성한 모바일 노드들은 지속적인 전원공급이 힘들기 때문에 자신의 한정된 에너지에 의존한다. 이러한 모바일 노드의 에너지 소비를 줄이기 위해 IEEE 802.11 PSM를 적용한 다중 홉 ad-hoc 네트워크 모델에 대해서 최근 많은 연구가 이루어졌다. 다중 홉 ad-hoc 네트워크에 802.11 PSM을 적용하면 송수신에 참여하지 않는 모바일 노드들의 에너지소비를 절약하게 되어 네트워크 활동시간을 증가시키게 된다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.54-54
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• 2004

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1347-1350
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• 2005

거의 모든 종류의 이동기기에서 에너지를 절감하는 것은 중요한 연구주제들중의 하나이다. 본 논문에서는 낮은 전원을 소모하는 슬립 모드로의 전환이 가능한 노드들로 구성된 MANET(mobile ad hoc networks)에서 에너지를 절감하는 새로운 프로토콜을 설계한다. 본 논문에서 고려하고 있는 MANET는 예측할 수 없는 호스트의 이동성, 멀티홉에서의 호스트들 간의 통신 그리고 비동기적인 메커니즘을 사용하는 특징을 가지고 있다. 특히 우리는 노드의 동기화가 에너지 절감 프로토콜의 복잡성에 어떤 영향을 미치는지에 대하여 연구한다. 또한 IEEE 802.11기반 multi-hop ad hoc network에 적용할 수 있고 동기적으로 전원을 관리하는 SPFAI(Synchoronous PFAI), ESPFAI(Efficient SPFAI), NSPFAI(Non-MTIM SPFAI)의 세가지 에너지 절감 프로토콜을 제안한다.

• The KIPS Transactions:PartC
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• v.14C no.7
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• pp.583-588
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• 2007

It is easy to implement a temporary network with a mobile ad-hoc network in which mobile nodes have without using a infrastructure network. They depend on their limited power. Recently, it is a hot issue to save the energy in a mobile ad-hoc network because a mobile nodes have a limited energy. Research of IEEE 802.11 PSM was proposed in a single hop ad-hoc assumption. If IEEE 802.11 PSM is applied to multi hop ad-hoc network, non-optimal paths will be generated by the mobile nodes which didn't receive a message of routing request. Non-optimal paths increase not only a network latency but also energy consumption of mobile nodes. Reconfiguring algorithm of non-optimal paths caused by the mobile nodes which didn't receive a message of routing request is proposed in this paper. A mobile node can overhear the data in his range. A wireless medium is shared by all mobile nodes using the same bandwidth. All mobile nodes lookout the non-optimal paths with these properties of a medium, if non-optimal path is generated, optimal reconfiguring will be accomplished by modifying routing table of itself or sending a request message of routing update to nearby nodes. By reconfiguring the non-optimal paths to optimized ones, network latency and energy consumption was decreased. It is confirmed to ignore the overhead caused by a algorithm presented in this paper through the result of the simulation.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.381-392
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• 2007

In this paper, we present an analytical method for estimating the saturation throughput of an 802.11 ad hoc LAN in the presence of noise distorting transmitted frames. This is the first method that allows studying analytically the 802.11 network performance with consideration of correlated channel failures usually inherent to realistic wireless channels. With the study, we consider the possible packet fragmentation that can be adopted to reduce the performance degradation caused by noise-induced distortions. In addition to the throughput, our method allows estimating the probability of a packet rejection occurring when the number of packet transmission retries attains its limit. The obtained numerical results of investigating 802.11 LANs by the developed method are validated by simulation and show high estimation accuracy as well as the method efficiency in determining the optimal fragmentation threshold.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.282-295
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• 2007

Due to the nature that high datarate leads to shorter transmission range, the performance enhancement by high datarate 802.11 WLANs may be degraded when applying high datarate to an 802.11 based multihop ad hoc network. In this paper, we evaluate, through extensive simulations, the performance of multihop ad hoc networks at multiple transmission datarates, in terms of the number of hops between source and destination, throughput, end-to-end delay and packet loss. The study is conducted based on both stationary chain topology and mesh topologies with or without node mobility. From numerical results on network performance based on chain topology, we conclude that there is almost no benefit by applying the highest datarate when the chain length is 6 hops or more. With node mobility in mesh topology, the benefit of using high datarate diminishes at even shorter number of hops. To explore the main reasons for this behavior, analyses on multihop end-to-end throughput and network k-connectivity have been conducted later in the paper, and correspondingly an auto-rate adaptation algorithm has been proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.516-528
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• 2015

In this paper, we propose mobile ad hoc network configuration and its autonomous network construction method for efficiency and scalability of media streaming for mobile smart devices. To provide scalable network configuration for streaming traffic distribution, an IEEE 802.11 infrastructure network and ad hoc networks are hierarchically built. The proposed method autonomously configures a hierarchical streaming network by competition based on performance and states of devices and the wireless network, not depending on any specific nodes. Finally, we conduct performance measurement for the proposed configuration and analyze the experimental result.