• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.180-186
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• 2017

In this paper we propose a traffic aware Demand Wakeup MAC(TADW-MAC) protocol, in which low data delay and high throughput can be achieved, for wireless sensor networks. With the TADW-MAC protocol, the problem of the DW-MAC protocol, which schedules only one packet to deliver during the Sleep period in a multi-hop transmission is resolved. DW-MAC is not adequate for the applications such as object tracking and fire detection, in which busty data should be transmitted in a limited time when an event occurs [6-8]. When an event occurs, duty cycle can be adjusted in the TADW-MAC protocol to get less energy consumption and low latency. The duty cycle mechanism has been widely used to save energy consumption of sensor node due to idle listening in wireless sensor networks. But additional delay in packet transmission may be increased in the mechanism. Our simulation results show that TADW-MAC outperforms RMAC and DW-MAC in terms of energy efficiency while achieving low latency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1173-1181
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• 2007

A number of routing algorithms have been studied for wireless mobile ad-hoc network. Among them, the AODV routing algorithm with on-demand method periodically transmits hello message and monitors link state during data transmission in order to maintain routing paths. When a path is disconnected, a node that senses it transmits a RERR packet to the transmitting node or transmits a RREQ locally so that the path could be repaired. With that, the control packet such as a RREQ is broadcast, which causes the consumption of bandwidth and incurs data latency. This paper proposes a LRRLBP algorithm that locally repairs a path by predicting link state before disconnecting the path based on the AODV routing protocol for solving such problems. Intensive simulations with the results using NS-2 simulator are shown for verifying the proposed protocol.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.25-34
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• 2011

In this paper, In this paper, we propose a Cooperative Routing Protocol (CooRP) for supporting network convergence and transmission services efficiently in mobile ad-hoc wireless sensor networks with Rayleigh fading environments. The main contributions and features of this paper are as follows. First, the routing routes are decided on route stability based on entropy concepts using mobility of nodes within the direction guided line region to increase the operational lifetime of routes as well as reduce control overhead for route construction. Second, a cooperative data transmission strategy based on the constructed stable routing route is used to increase packet delivery ratio with advanced SNR. Third, a theoretical analysis for cooperative data transmission of the proposed CooRP with outage probability is presented. The performance evaluation of the proposed CooRP is performed via simulation using OPNET and analysis. The results of performance evaluation show that the proposed CooRP by using stable routing routes and cooperative transmission can increase packet delivery ratio efficiently.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1225-1230
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• 2015

MAC protocol for WBAN performs CSMA/CA(:Carrier Sense Multiple Access with Collision Avoidance)algorithm that handles traffic which occurs in emergency with top priority in order to deal with variable data of sensor node for medicine. Emergency message that node sends undergoes collision and delay of transmission by retransmission of emergency message and waste of energy by retransmission. This paper suggests algorithm that minimizes loss of frame caused by collision and applies different backoff parameters by setting order of priority between MAC instruction frame and data frame in CSMA/CA algorithm case which applies order of priority queuing to improve aforementioned problem. According to performance evaluation, it has been found that using suggested MAC protocol showed lower collision probability, higher packet transmission processing ratio and lower packet loss compared with using IEEE 802.15.6.

• Convergence Security Journal
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• v.17 no.4
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• pp.11-16
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• 2017

MANET composed of only mobile node is applied to various environments because of its advantage which can construct network quickly in emergency situation. However, many routing vulnerabilities are exposed due to the dynamic topology and link failures by the movement of nodes. It can significantly degrade network performance. In this paper, we propose a secure routing protocol based on trust model. The domain-based network structure is used for efficient trust evaluation and management of nodes in the proposed technique. The reliability evaluation of nodes was performed by the discard ratio of control packet and data packet of the nodes. The abnormal nodes are detected by performing traffic check and inspecting of nodes on a path that generates excessive traffic in order to increase the efficiency of routing. It is confirmed through experiments of the proposed technique that data transmission is performed securely even if an attack exists on the path.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.548-553
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• 2019

Along with advanced vehicle to vehicle (V2V) communication technologies, platooning is regarded as one of the most promising form of autonomous driving solutions in order to increase road capacity. In this paper, we propose a novel V2V transmission scheme for safety message dissemination in platooning. The proposed scheme enhances the efficiency of channel access and multi-vehicle orthogonal frequency division multiple access (OFDMA) transmission by taking advantage of triggered uplink access technique and null data packet feedback report protocol introduced in the sixth generation WLAN standard, IEEE 802.11ax. The simulation results prove that the proposed scheme outperforms the conventional IEEE 802.11 transmission scheme throughout all measured vehicle density range.

• Journal of Communications and Networks
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• v.5 no.3
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• pp.266-274
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• 2003

One of the major issues in current on-demand routing protocols for ad hoc networks is the high resource consumed by route discovery traffic. In these protocols, flooding is typically used by the source to broadcast a route request (RREQ) packet in search of a route to the destination. Such network-wide flooding potentially disturbs many nodes unnecessarily by querying more nodes than is actually necessary, leading to rapid exhaustion of valuable network resources such as wireless bandwidth and battery power. In this paper, a simple optimization technique for efficient route discovery is proposed. The technique proposed herein is location-based and can be used in conjunction with the existing Location-Aided Routing (LAR) scheme to further reduce the route discovery overhead. A unique feature of our technique not found in LAR and most other protocols is the selective use of unicast instead of broadcast for route request/query transmission made possible by a novel reuse of routing and location information. We refer to this new optimization as the UNIQUE (UNIcast QUEry) technique. This paper studies the efficacy of UNIQUE by applying it to the route discovery of the Dynamic Source Routing (DSR) protocol. In addition, a comparative study is made with a DSR protocol optimized with only LAR. The results show that UNIQUE could further reduce the overall routing overhead by as much as 58% under highly mobile conditions. With less congestion caused by routing traffic, the data packet delivery performance also improves in terms of end-to-end delay and the number of data packets successfully delivered to their destinations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1B
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• pp.59-66
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• 2012

The use of MPSoC has been increasing because of a rise of use of mobile devices and complex applications. For improving the performance of MPSoC, number of processor has been increasing. Standard MPI is used for efficiently sending data in distributed memory architecture that has advantage in multi processor. Standard In this paper, we propose a scalable distributed memory system with a low cost hardware message passing interface(MPI). The proposed architecture improves transfer rate with buffered send for small size packet. Three queues, Ready Queue, Request Queue, and Reservation Queue, work as previous architecture, and two queues, Small Ready Queue and Small Request Queue, are added to send small size packet. When the critical point is set 8 bytes, the proposed architecture takes more than 2 times the performance improvement in the data that below the critical point.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.3
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• pp.22-30
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• 2001

This paper investigated future telemedicine as implementation of the telemonitoring system using LAN environment. For telemonitoring system rapidly implementation used the PC compatible embedded computing system in the ROMDOS and application program used the WATTCP that free TCP/IP Stack. Host computer program - programed by Visual C++ - had saved ECG signal and Patient Data coming inside Embedded PC and displayed. Embedded PC acquired ECG signal and transmitted a Packet to Host Computer. Host Computer remote access Embedded PC. This structure is the same Client/Sever Model. This system will be basic telemedicine model. There are problems of realtime telemonitoring because of network delay and data packet. Because of these problems, telemedicine systems will be required faster network speed and method of bio-signal transmission.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.6
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• pp.9-17
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• 2012

High-quality multimedia on the Internet has attracted attention because of its wide application area. IP multicast has been proposed as a solution to use efficient network resources in these services. However, IP multicast has not been commonly used due to a number of practical issues such as security and management. As an alternative, an overlay multicast routing which is performed in upper protocol layers on legacy networks without changing hardware has been presented. Yet, the maximum data transmission capacity of the overlay multicast is not sufficient for real time transmission of multimedia data. In this paper, we have implemented an overlay multicast engine on NetFPGA which allows us to perform packet replication and tunneling which need high-speed. In addition, we have implemented extra portions which need low-speed in software. From now on, we will progress research which increase the number of terminal spots which can be replicated by improvement and amplify throughputs by optimization.