• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.2
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• pp.95-108
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• 1999

The CDMA mobile system consists of several subsystems and each subsystem has many processing elements that handle voice messages and control messages for performing CDMA call processing functions through CDMA Interconnection Network(CIN). For assuring a high throughput and a short delay in the CIN, an efficient medium access control protocol should be provided. In this paper, we propose a new access control protocol of CIN for providing real time communications in CDMA mobile system. Also, we evaluate the delay performance of the proposed access control protocol and compare it with that of the existing access control protocol. Through a set of numerical examples, we show that our proposed protocol provides a better delay performance than the existing protocol.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.25-27
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• 2004

Power Saving는 Portable 무선 기기 전반에 걸쳐 중요한 연구 과제로서, 에너지 절감을 위해 많은 protocol들이 제안되고 있다. 한편 에너지의 절감은 송수신 성능의 감소라는 문제점을 갖기 때문에 PS(Power Saving) protocol 설계상의 주요 과제는 이 trade-off에 대하여 송수신성능의 희생을 최소화 하면서 에너지 절감율을 대폭 향상 시키는 데에 있다. 본 논문에서는 저자들이 [1]에서 이미 제안한 바 있는 SPFAI(Synchronized Periodically-Fully-Awake-Interval ) Protocol을 개선하여 한층 더 효율적인 PS protocol을 제시하고 기존 SPFAI과의 성능비교를 위하여 대표적인 공개 network simulator인 NS2[2]를 이용하여 제안된 protocol의 성능을 검증한다.

• Journal of Internet Computing and Services
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• v.3 no.3
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• pp.95-104
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• 2002

The interworking for voice service between next generation mobile network and traditional network can be deployed better flexible and expansible network conditions with providing efficiency and economy of network at the same time. So it is essential to develop the interworking strategies together with a evolved network and traditional network. This paper describes a design and verification of internetworking protocol for CC of next generation mobile network and SIP of IP network for applying interworking technology to next generation mobile network, which can harmoniously expropraise voice service from traditional network.

• ETRI Journal
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• v.34 no.5
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• pp.775-778
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• 2012

We propose integrating random network coding with the Enhanced On-Demand Multicast Routing Protocol (E-ODMRP). With the Network Coded E-ODMRP (NCE-ODMRP), we present a framework that enables a seamless integration of random linear network coding with conventional ad hoc multicast protocols for enhanced reliability. Simulation results show that the NCE-ODMRP achieves a nearly perfect packet delivery ratio while keeping the route maintenance overhead low to a degree similar to that of the E-ODMRP.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.91-105
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• 2010

A wireless sensor network communication technique has been broadly studied with continuous advances in ubiquitous computing environment. Especially, because the resource of the sensor node is limited, it is important to reduce the communication energy by using an energy-efficient routing protocol. The existing cluster-based routing protocols have a problem that they cannot select a cluster head efficiently by randomly choosing a head. In addition, because the existing cluster-based routing protocols do not support the large scale of network, they cannot be used for various applications. To solve the above problems, we, in this paper, propose a new cluster-based routing protocol using representative paths. The proposed protocol constructs an efficient cluster with distributed cluster heads by creating representative paths based on hop count. In addition, a new routing protocol supports multi-hop routing for data communication between a cluster member node and a cluster head as well as between cluster heads. Finally, we show that our protocol outperforms LEACH and Multihop-LEACH in terms of reliability and scalability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.188-195
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• 2012

Many systems are developing for the realization of NCW(Network Centric Warfare). UAV(Unmanned Aerial Vehicle) Network is attracting attention in a lot of military applications. In general, UAVs have the potential to create an ad-hoc network and greatly reduce the hops from source to destination. However, UAV networks exhibit unique properties such as high mobility, high data rate, and real time service. The routing protocols are required to design the multi-hop routing protocols that can dynamically adapt to the requirements of UAV network. In this paper we analyse Geographic Routing Protocol is based on geographical distance between source and destination for efficient and reliable transmission. Geographic Routing Protocol is evaluated in video service scenarios with TDMA model in our simulation. The simulation results show that the performance of Geographic Routing Protocol is better than the MANET Routing Protocol in terms of packet received ratio, end to end delay, and routing traffic sent.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.151-161
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• 2009

The PULSE protocol can greatly reduce power consumption using a node's sleep state. But this protocol does not consider movement of a sink node in a sensor network. In the mobile sensor network a routing protocol must recover path error by movement of a sink node as quickly as possible. Therefore we have to achieve fast path recovery and power saving to support movement of a sink node in a sensor network. This paper proposes the Mobile PULSE protocol which is a improved routing protocol for a mobile sink node. And we evaluate Mobile PULSE and show that the Mobile PULSE reduces the recovery time about 40% compared with original PULSE protocol. Mobile PULSE increases energy consumption than PULSE as a maximum of 0.8%, which means Mobile PULSE is similar to PULSE in energy consumption. This paper shows mobile PULSE's capability in the mobile sensor network through evaluation of path recovery time and power consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.351-359
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• 2010

In this paper, we propose a transmission algorithm of the TLI protocol of the IEC 61162-4 standard to perform the e-Navigation on ship, and we design and implement the TLI protocol according to the proposed algorithm. The implemented protocol is a TCP/IP based protocol, and is a network protocol with the MAU and LNA components proposed in the IEC 61162-4 standard. In addition, it makes a data transmission over the network architecture based on client/server network model. In the implemented protocol, there are a communication between the MAU and the LNA in one host, and also a communication between the LNA and the LNA in each other hosts. In order to provide a variety of service in a host, every client host has a LNA and multiple MAUs. According to the standard specification and the proposed transmission algorithm, we designed and implemented the TLI protocol using object-oriented mechanism. We carried out the experiment under a simple network model similar to real ship environment, and confirmed that it successfully transmits and receives data between the hosts.

• Journal of Internet Computing and Services
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• v.10 no.6
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• pp.27-36
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• 2009

PSTN (public switched telephone network) provides voice communication service, whereas IP network provides data oriented service, and we can use IP network for multimedia transport service (e.g. voice over IP service) with economic price. In this paper, we propose RoIP (robot on IP) service scenario, signaling call flow, and implementation to provide home automation and monitoring service for remote site users. In our scheme, we used a extended SIP (session initiation protocol) for signaling protocol between remote site users and home robots. For our bearer transport control, we implemented H.263 video codec over RTP (real-time transport protocol) and additionally DTMF (dual tone multi-frequency) transport for robot actuator control. We implemented our scheme on home robots and experimented with KTF operator network, and it shows good communication quality (average MOS = 9.15) and flexible robot controls.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.51-57
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• 2009

Ubiquitous sensor network is the communication environment where sensor nodes move freely and construct network to get the services from the system. So, it does not need fixed infrastructure and can easily be placed in unaccessible regions like war or calamity area. Wireless sensor network protocol has self-organizing capability, need to adapt topology change flexibly and also has technique that sensor nodes work cooperatively, because network disconnection is frequently occurred due to the active mobility of sensor nodes. In this paper, we design a cluster based fault-tolerant routing protocol for the efficient topology construction and to guarantee stable data transmission in USN. The performance of the proposed protocol is evaluated by an analytic model.