• Journal of Communications and Networks
• /
• v.4 no.4
• /
• pp.336-343
• /
• 2002

A major challenge for next generation mobile communication is capturing the system architecture’s complexity with all its internal and external dependencies. Seamless integration of heterogeneous environments in all system parts is a key requirement. Moreover, future systems have to consider the different evolution cycles of individual system parts. Among those, services are expected to change the fastest. With respect to these considerations, we propose an overall architecture for next generation mobile communication systems. It covers all system parts from wireless transmission to applications including network and middleware platform. Our approach focuses on adaptability in terms of recon- figurability and programmability to support unanticipated system evolution. Therefore, we consider abstraction layers which consist of adaptable cooperating components grouped by open platforms rather than rigid system layers. In addition to that, we introduce cross-layer cooperation allowing an efficient use of the available resources. Specific scenarios illustrate the feasibility of our approach.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.4
• /
• pp.493-498
• /
• 2011

In this paper, Transmission performance over MANET(Mobile Ad-hoc Networks) under DDoS Intrusions is evaluated. Intrusion counterplan requirement, which have to be used for MANET under DDoS intrusions, is suggested through this evaluation. VoIP simulator based on NS-2 network simulator is used for performance measurement. MOS, network delay, packet loss rate and call connection rate is measured with this simulation. Finally, requirement of intrusion continuing time shorter then 10 seconds is suggested for VoIP service over MANETs under DDoS intrusions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.3
• /
• pp.439-444
• /
• 2017

Wireless sensor network technology is a rapidly growing technology of ubiquitous computing environment and application and research are being carried out in various fields. The sensor nodes constituting the wireless sensor network maintain the life cycle by using the battery in the distributed network environment, so energy efficiency is more important than QoS requirement. In MAC protocol of IEEE802.15.4, MAC protocol study adaptive to traffic and standardization work emphasizing reliability and efficiency in wireless sensor network environment are underway. but, Wireless sensor networks have the problem that the response speed of the sensor node drops as the energy efficiency decreases. In this paper, we designed the MAC protocol with improved energy efficiency of the whole network by analyzing the MAC protocol of the synchronous method and the hybrid method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.414-416
• /
• 2010

WiBro network technologies developed mainly by Korea are one of very promising 4G technologies. WiBro has been standardized as international standard called Mobile WiMAX, and has been deployed in many countries. Emergency Services are infrastructural servicesa and very essential to induce subscribers from other types of networks. This paper propose a network architecture for supporting emergency services for mobile VoIP services in WiBro networks. The proposed architecture is based on WMF's architecture for internationa compatibilities, and reflects national considerations on interfacing PSAP for domestic compatibilities.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4C
• /
• pp.273-281
• /
• 2002

Recently, demand for real-time data and multimedia data is rapidly increasing, and it is impossible for mobile Ad Hoc networks with only best effort service to efficiently transfer such data. So, we absolutely need the QoS service which reserves the communication resources in advance. The existing routing protocols, which assume that the links between nodes are bidirectional, provide the convenience for the route discovery and maintenance, but can not support the routing function for the unidirectional links due to the wireless link property easily changing with time under the real wireless environment. In order to solve such problems, in this dissertation we suggested a unidirectional QoS routing a waste of communication resources. The waste of protocol that supports unidirectional links and reduces communication resources is reduced by establishing the shortest route suitable to QoS support, considering in advance the usable communication resources at each node.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.49 no.4
• /
• pp.26-33
• /
• 2012

Please WBAN(Wireless Body Area Networks) is wireless communication of within 3 m radius from inside and outside of the body. WBAN is many uses IEEE 802.15.4 MAC protocol for WBAN MAC protocol requirements. IEEE 802.15.4 MAC protocol applies GTS(Guaranteed Time Slot) allocation scheme for guarantee packet delivery of application which requests QoS(Quality of Service). However, GTS allocation scheme of IEEE 802.15.4 MAC protocol uses FIFS(First In First Service) queueing. So it reduces data transmission reliability and has many problems. Therefore, IEEE 802.15.4 applies not WBAN MAC protocol for emergency data transmission. In this paper, we proposes a priority based MAC protocol for emergency data transmission in wireless body area networks. the proposal MAC protocol sets priority the data. So GTS reqeuest throughput of emergency data increasing and GTS allocation delay of emergency data decreasing.

• The KIPS Transactions:PartC
• /
• v.16C no.2
• /
• pp.143-150
• /
• 2009

In trust-based networks, it is very important how to decide a node is trustworthy when one node performs communications with other node. In current networks based on trust, a node creates a new trust value from observation and then establishes an intercommunication path through the process of evaluating a targeted communication node. In our paper, we propose four trust models in which a new node enters a cluster and finds a target node to create a communication in ad-hoc networks. The proposed models have been classified according to the existence of reputation server and the trust evaluation functions. Through the proposed model, we found that new node finds target node more quickly in which there exists a reputation server in the cluster and considers neighbor node's recommendation as well as own experience information when calculates trust values. As our performance analysis, we focus the communication delay time to generate a final trust value for each trust model.

• Electronics and Telecommunications Trends
• /
• v.39 no.4
• /
• pp.21-31
• /
• 2024

Major global powers are investing heavily in artificial intelligence (AI) and hyper-connected networks, demonstrating their crucial role in future warfare. To advance and utilize AI in national defense, it is essential to have policy support at the governmental or national level. This includes establishing a research and development infrastructure, creating a common development environment, and fostering AI expertise through education and training programs. To achieve advancements in hyper-connected networks, it is essential to establish a foundation for a robust and resilient infrastructure by comprehensively building integrated satellite, aerial, and ground networks, along with developing 5G & edge computing and low-orbit satellite communication technologies. This multi-faceted approach will ensure the successful integration of AI and hyper-connected networks, strengthening national defense and positioning nations at the forefront of technological advancements in warfare.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.4
• /
• pp.168-180
• /
• 2018

Due to the spread of mobile devices and the introduction of high-quality services, mobile traffic is expected to increase sharply and overload of cellular networks is expected. D2D communication is a way to reduce the load and evolve to 5th generation. Since D2D communication directly communicates between the terminals, it can reduce the overload of the cellular network and improve energy efficiency, data rate and network performance. This paper proposes a D2D handover scheme for D2D communication in cellular networks. The cellular network is a 3GPP EPS, and the proposed D2D handover method improves the existing EPS handover process considering compatibility between existing EPS and D2D communication. We also demonstrate the superiority of the proposed handover scheme using the network simulator ns-3. Simulation results show that the proposed handover scheme is superior to existing handover methods in terms of CUE variation, packet transmission delay time, and throughput.

• Journal of Communications and Networks
• /
• v.10 no.4
• /
• pp.455-464
• /
• 2008

To provide network services consistently under various network failures, enterprise networks increasingly utilize path diversity through multi-homing. As a result, multi-homed non-transit autonomous systems become to surpass single-homed networks in number. In this paper, we address an inevitable problem that occurs when networks with multiple entry points deploy firewalls in their borders. The majority of today's firewalls use stateful inspection that exploits connection state for fine-grained control. However, stateful inspection has a topological restriction such that outgoing and incoming traffic of a connection should pass through a single firewall to execute desired packet filtering operation. Multi-homed networking environments suffer from this restriction and BGP policies provide only coarse control over communication paths. Due to these features and the characteristics of datagram routing, there exists a real possibility of asymmetric routing. This mismatch between the exit and entry firewalls for a connection causes connection establishment failures. In this paper, we formulate this phenomenon into a state-sharing problem among multiple fire walls under asymmetric routing condition. To solve this problem, we propose a stateful inspection protocol that requires very low processing and messaging overhead. Our protocol consists of the following two phases: 1) Generation of a TCP SYN cookie marked with the firewall identification number upon a SYN packet arrival, and 2) state sharing triggered by a SYN/ACK packet arrival in the absence of the trail of its initial SYN packet. We demonstrate that our protocol is scalable, robust, and simple enough to be deployed for high speed networks. It also transparently works under any client-server configurations. Last but not least, we present experimental results through a prototype implementation.