• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.769-772
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• 2003

Middleware enables different networking devices and protocols to inter-operate in ubiquitous home network environments. The UPnP(Universal Plug and Play) middleware, which runs on a PC and is based on the IPv4 protocol, has attracted much interest in the field of home network research since it has versatility. The UPnP, however, cannot be easily accessed via the public Internet since the UPnP devices that provide services and the Control Points that control the devices are configured with non-routable local private or Auto IP networks. The critical question is how to access UPnP network via the public Internet. The purpose of this study is to deal with the non-routability problem in local private and Auto IP networks by improving the conventional Control Point used in UPnP middleware-based home networks. For this purpose, this paper proposes an improved Control Point for accessing and controlling the home network from remote sites via the public Internet, by adding a web server to the conventional Control Point. The improved Control Point is implemented in an embedded GNU/Linux system running on an ARM9 platform.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2205-2217
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• 2015

Bio-inspired routing protocol uses a principle of swarm intelligence, which finds the optimal path to the destination in a distributed and autonomous way in dynamic environments, so that it can maximize routing performances, reduce control overhead, and recover a path failure quickly according to the change of network topology. In this paper, we propose a bio-inspired routing protocol for mobile ad hoc networks. The proposed scheme uses a function of overhearing via wireless media in order to obtain the routing information without additional overhead. Through overhearing, the pheromone is diffused around the shortest path between the source and destination. Based on this diffused pheromone, a probabilistic path exploration is executed and the useful alternative routes between the source and destination are collected. Therefore, the proposed routing protocol can ensure the up-to-date routing information while reducing the control overhead. The simulation results show that the proposed scheme outperforms the typical AODV and AntHocNet protocols in terms of routing performances and significantly decreases the routing overhead against the AntHocNet.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.205-215
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• 2002

In this paper the Dynamic Minislot Reservation Protocol(DMRP) in which the control channel is divided into contention-less and contention minislots in order to reduce re-transmission probability in multicasting is proposed. In the network, earth node has two pairs of transceivers. A transceiver consisting of a fixed transmitter and a fixed receiver is used to control packet registration and the other transceiver is used to transmit data. Two types f transceivers for data transmission are considered : one is FT-TR(Fixed Transmitter-Tunable Receiver) and the other is TT-TR(Tunable Transmitter-Tunable Receiver). In the analysis, FT-TR and TT-TR single-hop passive star networks are compared. As results, we conclude that the DMRP protocol with dynamically divided control channel has improved the system performance such as throughput and system delay regardless of traffic type or network structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1532-1538
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• 1999

In general, because error rate of wireless link is higher than that of wired link, DLC layer protocol for wired network with low error rate is not proper for wireless environments. In addition, the conventional DLC layer protocol for wireless network is optimized for the low-speed data service, so it is difficult to use conventional DLC protocol in the current mobile communication environments handing high-speed and multimedia services. Therefore, a DLC layer protocol that is suitable to current wireless communication environments is required. In this paper, we propose a novel error control scheme that supports a variety of traffic attribute and is applicable to high-speed and multimedia data service in WATM. The proposed scheme provides enhanced throughput performance for real-time traffic by using modified ASR ARQ without ACK and reduces loss rate by using FEC in the case of high error condition. Also, for non real-time traffic, the use of ASR ARQ without ACK enhances throughput performance and delay time is decreased by using FEC in the case of high error rate channel. As a result of simulation, the proposed scheme has better performance than conventional ASR ARQ protocol in view of delay and throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9B
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• pp.589-597
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• 2007

In this paper, a WDM metro ring consisting of access nodes with $FT-FR^n$ (Fixed Transmitter - n Fixed Receivers) is considered. A trade-off exists between node throughput and transmission fairness because the access nodes share wavelength channels. In order to eliminate the transmission unfairness and to increase throughput, the p-persistent medium access control (MAC) protocol is proposed: each node uses an empty optical slot to transmit a packet and make it available with the extraction of a transferred packet at the source access node, called source-stripping. The local empty slot can be used to transfer a head-of-line packet in the local buffer with probability p or it is used for the next downstream nodes with 1-p. The proposed MAC protocol provides better node throughput than the non-persistent protocol and exhibits better fairness index than the 1-persistent protocol in WDM ring networks. In addition, numerical analysis shows that the proposed MAC protocol maximizes the node throughput under uniform traffic conditions. For more detailed results, we use the network simulation under Poisson and self-similar traffic. Furthermore, unpredictable traffic constructed by the combination of the former and the latter is also considered. The reasonable probability of the p-persistent protocol for a given architecture can be determined through simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.764-784
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• 2017

Energy efficiency is an essential requirement in designing a MAC protocol for wireless sensor networks (WSNs) using battery-operated sensor nodes. We proposed a new receiver-initiated MAC protocol, RIX-MAC, based on the X-MAX protocol with asynchronous duty cycles. In this paper, we analyzed the performance of RIX-MAC protocol in terms of throughput, delay, and energy consumption using the model. For modeling the protocol, we used the Markov chain model, derived the transmission and state probabilities, and obtained the equations to solve the performance of throughput, delay, and energy consumption. Our proposed model and analysis are validated by comparing numerical results obtained from the model, with simulation results using NS-2.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.606-613
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• 2012

In a smart grid environment, data for the usage and control of power are transmitted over an Internet protocol (IP)-based network. This data contains very sensitive information about the user or energy service provider (ESP); hence, measures must be taken to prevent data manipulation. Mutual authentication between devices, which can prevent impersonation attacks by verifying the counterpart's identity, is a necessary process for secure communication. However, it is difficult to apply existing signature-based authentication in a smart grid system because smart meters, a component of such systems, are resource-constrained devices. In this paper, we consider a smart meter and propose an efficient mutual authentication protocol. The proposed protocol uses a matrix-based homomorphic hash that can decrease the amount of computations in a smart meter. To prove this, we analyze the protocol's security and performance.

• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.291-294
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• 2004

Wireless sensor network을 위 한 MAC(Medium Access Control) layer를 low-rate WPAN을 목적으로 한 IEEE 802.15.4 사양에 따라 구현하고 검증하였다. 센서 네트워크의 노드는 배터리로 동작하므로 에너지 소모가 가장 큰 걸림돌이 된다. power saving을 위한 몇 가지 방법을 포함한 IEEE 802.15.4 MAC protocol을 구현함으로써 wireless sensor network에 적용 가능함을 보였다.

• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1223-1234
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• 2002

RTP payload must be encrypted for providing commercial VOD service or private video conference over the Internet. Encryption/decryption delay is minimized because there are constraints in transporting a multimedia data through the Internet. Therefore, encryption algorithm is changed with considering network traffic md load. During many users participate in the same multimedia service, an user who already left the service can receive and decrypt the RTP payload because of knowing the encryption key. In this paper, Security Control Protocol for RTP is designed and implemented for changing the encryption algorithm and the key.