• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1091-1096
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• 2015

In this paper, WiMedia Distributed-MAC protocol is adopted for development of multi-hop N-screen wireless services. Furthermore, to provide the multi-hop OSMU (One Source Multi Use) N-screen service through P2P streaming in the D-MAC protocol, a new multi-hop resource reservation scheme is proposed and analyzed to reduce end to end delay. For this Multi-hop resource reservation scheme, a new MSCDRP (Multi-Stage Cooperative DRP) IE is proposed. Simulation results show that our multi-hop MSCDRP scheme reduces the end to end delay and increases throughput at various multi-hop N-screen network environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.16-27
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• 2012

In multi-interface multi-channel(MIMC) based tactical ad hoc networks, QoS support for required operational capacity is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop channel contention results in a degradation of end-to-end delay for multi-hop transmissions. The basic idea of our scheme is to make a "multi-hop reservation" at the MAC layer by using the modified RTS frame. It contains additional information such as destination information, packet priority, and hop count, etc. In addition, we differentiate the contention window area according to the packet priority and the number of hops to deliver packets in the predefined allowed latency. Our scheme can minimize the multi-hop delay and support the QoS of the critical data in real time(i.e., VoIP, sensing video data, Video conference between commanders). Our simulation study and numerical analysis show that the proposed scheme outperforms the IEEE 802.11 MAC.

• Journal of information and communication convergence engineering
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• v.14 no.1
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• pp.21-25
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• 2016

N-screen is a promising technology to improve support for multimedia multicasting, content sharing, content mobility, media scalability, and seamless mobility. In this paper, the WiMedia distributed-MAC (D-MAC) protocol is adopted for development of a seamless N-screen wireless service. Furthermore, to provide a multi-hop, one source multi-use N-screen service through point to point streaming in a seamless D-MAC protocol, a dynamic multi-frame transmission technology is proposed. In this technology, a dynamic time slot allocation scheme and a multi-hop resource reservation scheme are combined. In the proposed dynamic time slot allocation scheme, two thresholds, a hard threshold and a soft threshold, are included to satisfy the power consumption and delay requirements. A multi-frame DRP reservation scheme is proposed to minimize end-to-end delay during the multi-hop transmissions between N-screen devices. The proposed dynamic multi-frame transmission scheme enhances N-screen performance in terms of the multi-hop link establishment success rate and link establishment time compared to the conventional WiMedia D-MAC system.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.279-282
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• 2003

This paper proposes a medium-access control(MAC) protocol designed for wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy sayings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.950-956
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• 2015

In this paper, a WiMedia Distributed-MAC (D-MAC) protocol is adopted for development of a seamless N-screen wireless service in Indoor and Ship Area Networks. Furthermore, to provide the OSMU (One Source Multi Use) N-screen service through P2P streaming in the seamless D-MAC protocol, a ATMT (Asynchronous Traffic Multi-hop Transmission) technology is proposed and analyzed. In this system, a WiMedia ATMT D-MAC bridge transmits control and managing information to various sensors and instruments, from a central integrated ship area network station. For this technology, a time slot allocation scheme for WiMedia asynchronous traffic and a multi-hop resource reservation scheme are combined to evaluate the performance of each scheme. From simulation results, the proposed ATMT scheme enhances performances in viewpoints of N-screen asynchronous data latency and throughput, compared to the conventional WiMedia D-MAC system.

• Journal of Information Processing Systems
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• v.4 no.2
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• pp.41-52
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• 2008

In this paper, we discuss a novel reservation-based, asynchronous MAC protocol called 'Multi-rate Multi-hop MAC Protocol' (MMMP) for multi-hop ad hoc networks that provides QoS guarantees for multimedia traffic. MMMP achieves this by providing service differentiation for multirate real-time traffic (both constant and variable bit rate traffic) and guaranteeing a bounded end-to-end delay for the same while still catering to the throughput requirements of non real time traffic. In addition, it administers bandwidth preservation via a feature called 'Smart Drop' and implements efficient bandwidth usage through a mechanism called 'Release Bandwidth'. Simulation results on the QualNet simulator indicate that MMMP outperforms IEEE 802.11 on all performance metrics and can efficiently handle a large range of traffic intensity. It also outperforms other similar state-of-the-art MAC protocols.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.63-74
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• 2012

Multicast data communication is an efficient communication scheme, especially inmulti-hop ad hoc networks where the media access control (MAC) layer is based on one-hop broadcast from one source to multiple receivers. Compared to unicast, multicast over a wireless channel should be able to deal with varying channel conditions of multiple users and user mobility to provide good quality to all users. IEEE 802.11 does not support reliable multicast owing to its inability to exchange request-to-send/clear-to-send and acknowledgement packets with multiple recipients. Thus, several MAC layer protocols have been proposed to provide reliable multicast. However, additional overhead is introduced, as a result, which degrades the system performance. In this paper, we propose an efficient wireless multicast MAC protocol with small control overhead required for reliable multicast in multi-hop wireless ad hoc networks. We present analytical formulations of the system throughput and delay associated with the overhead.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.209-211
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• 2005

This paper proposes a adaptive medium-access control(MAC) protocol designed for low-power wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy savings.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.231-234
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• 2003

In this paper, we propose the enhanced CSMA/CA MAC protocol fir mobile multi-hop wireless Ad-hoc networks. In the conventional wireless Ad-hoc network such as WLAN using CSMA/CA MAC protocol, communications between terminals that fn connected within multi-hop node may degrade the transmission efficiencies as increasing the multi-hop nodes because of RTS-CTS-DATA-ACK message exchange between terminals. In this raper, we apply the ACK/RTS control message into multi-hop transmission between terminals for wireless ad-hoc networks and improve the data traffic transmission efficiencies compared with conventional CSMA/CA MAC protocol used in WLAN.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.177-185
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• 2008

Research on media access control (MAC) scheme for Wireless Sensor Network (WSN) has been mainly focused on energy efficiency improvement, while interest on latency is relatively weak. However, end-to-end latency could be a critical limitation specifically in the multi-hop network such as wireless multimedia sensor networks. In this paper we propose a media access control scheme with distributed transmission power control to Improve end-to-end transmission latency as well as reduce power consumption in multi-hop wireless sensor networks. According to the simulation results, the proposed scheme is turned out to be an energy efficient scheme with improved end-to-end transmission latency.