• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1282-1287
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• 2002

In this Paper, we present the design of 10Mbps HomePNA(Home Phoneline Networking Alliance) PHY which is Home Network Technology using phone-line. It is connected with external interface through MII(Media Independent Interface) and AFE(Analog Front End) Interface. 10Mbps HomePNA PHY is composed with Management Block IEEE 802.3 CSMA/CD MAC(Media Access Control) Block Modulator block and Demodulator block. For their verification, we designed a prototype FPGA PCB board using XPC860T made in Motorola. We verified HomePNA frame data transmission using a driver program based Linux kernel. we verified rate negotiation by HomepNA 2.0 Link Layer Protocol.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.455-460
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• 2006

Currently, the IETF group is working on service differentiation in the Internet. However, in wireless environments such as Ad-hoc networks, where channel conditions are variable and bandwidth is scarce, the Internet differentiated services are suboptimal without lower layers' support. The IEEE 802.11 standard for Wireless LANs is the most widely used WLAN standard today. 1t has a mode of operation that can be used to provide service differentiation, but it has been shown to perform badly. In this paper, we present a new service differentiation scheme for support QoS in the wireless IEEE 802.11, which is based on a multiple queuing system to provide priority of user's flow. We simulate and analyze the performance of our algorithm and compare its performance with the original IEEE 802.11b protocol. Simulation results show that our approach increases overall throughput in the MAC layer.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.10
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• pp.59-68
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• 1993

This paper describes implemation of 'General-purpose ETRI MAP interface module' (GEM) for Mini-MAP network. GEM operates as a Mini-MAP node in our FA system. To communicate between GEM and programmable devices(PD) such as PLC and CNC, serial communication is used. Application programs of a MiNi-MAP host system control and monitor programmable devices via GEM. GEM is implemented and tested on the basis of the MAP 3.0. TBC in the Nini-MAP board performs the function of the MAC sublayer. The LLC sublayer is implemented according to the specification of Class 3 that includes Type 1 and 3. And the MMS services are designed within the scope of implementation class MAP3. All the softwares are implemented under the real-time multitask OS for real-time application of the Mini-MAP and they are loaded into PROMs at the network board of GEM. We tested the LLC functions to make use of a protocol analyzer for the token-passing protocol. Also the MMS conformance test was carried out by exchanging primitives between GEM and a MMS product that had already passed the conformance test. Therefore GEM is proposed as a network tool of Computer Integrated Manufacturing (CIM) to integrate PDs which don't support MAP functions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1033-1036
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• 2013

A study about collision resolution is needed because huge file, video and multimedia information are transmitted to wireless LAN. CSMA/CR protocol guarantees fairness, but doesn't consider QoS. To practicalize CSMA/CR protocol in saturation fully-connected single hop network environments, this paper proposes method of collision compensation. previous CSMA/CR protocol chooses CR Slot only considering fairness, but this paper chooses front CR Slot for compensation of collision to station experiencing collisions. The station transmits jam signal and has channel priority of transmission. So transmitting efficiency and successful transmission probability rise. This proposed simple method can offer benefit to station experiencing collisions without additional hardware cost.

• Journal of IKEEE
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• v.22 no.3
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• pp.878-881
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• 2018

In this paper, experiments through performance evaluation under real operation environment were conducted. Transceiver and microcontroller shows the characteristics for the amount of current consumption and software protocol was optimized by controlling the time of Report Attribute and electric current level. To reduce current consumption when using battery, with designing transmission of the same amount of data as soon as possible, power consumption efficiency was enhanced.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.213-220
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• 2008

This paper analyzes a broadcasting technique for wireless multi-hop sensor networks that uses a form of cooperative diversity called opportunistic large arrays (OLAs). We propose a method for autonomous scheduling of the nodes, which limits the nodes that relay and saves as much as 32% of the transmit energy compared to other broadcast approaches, without requiring global positioning system (GPS), individual node addressing, or inter-node interaction. This energy-saving is a result of cross-layer interaction, in the sense that the medium access control (MAC) and routing functions are partially executed in the physical (PHY) layer. Our proposed method is called OLA with a transmission threshold (OLA-T), where a node compares its received power to a threshold to decide if it should forward. We also investigate OLA with variable threshold (OLA-VT), which optimizes the thresholds as a function of level. OLA-T and OLA-VT are compared with OLA broadcasting without a transmission threshold, each in their minimum energy configuration, using an analytical method under the orthogonal and continuum assumptions. The trade-off between the number of OLA levels (or hops) required to achieve successful network broadcast and transmission energy saved is investigated. The results based on the analytical assumptions are confirmed with Monte Carlo simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.793-801
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• 2022

Most Bluetooth devices are commonly used in various ways these days, but they can be often lost due to small-size devices. However, most Bluetooth protocol do not provide authentication functions to legitimate owners, and thus someone who obtains the lost Bluetooth device can easily connect to their smart devices to use it. In this paper, we propose NBAS can authenticates legitimate owners using NFT on lossy Bluetooth devices.NBAS generates a digital wallet on the blockchain using the decentralized network Ethereum blockchain and facilitating the MAC address of the Bluetooth device in the digital wallet. The owner of the wallet uses a private key to certify the Bluetooth device using NFT. The initial pairing time of NBAS was 10.25 sec, but the reconnection time was 0.007 sec similar to the conventional method, and the pairing rejection time for unapproved users was 1.58 sec on average. Therefore, the proposed NBAS effectively shows the device authentication over the conventional Bluetooth.

• Journal of KIISE
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• v.44 no.2
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• pp.213-222
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• 2017

The Internet of Things (IoT) technology is rapidly developing in recent years, and is applicable to various fields. A smart factory is one wherein all the components are organically connected to each other via a WSN, using an intelligent operating system and the IoT. A smart factory technology is used for flexible process automation and custom manufacturing, and hence needs adaptive network management for frequent network fluctuations. Moreover, ensuring the timeliness of the data collected through sensor nodes is crucial. In order to ensure network timeliness, the power consumption for information exchange increases. In this paper, we propose an IEEE 802.15.4e DSME-based distributed scheduling algorithm for mobility support, and we evaluate various performance metrics. The proposed algorithm adaptively assigns communication slots by analyzing the network traffic of each node, and improves the network reliability and timeliness. The experimental results indicate that the throughput of the DSME MAC protocol is better than the IEEE 802.15.4e TSCH and the legacy slotted CSMA/CA in large networks with more than 30 nodes. Also, the proposed algorithm improves the throughput by 15%, higher than other MACs including the original DSME. Experimentally, we confirm that the algorithm reduces power consumption by improving the availability of communication slots. The proposed algorithm improves the power consumption by 40%, higher than other MACs.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.331-341
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• 2015

In this paper, real-time water quality monitoring system of small water supply facilities based on IEEE 802.15.4e-2012 DSME MAC and IEEE 802.15.4g-2012 PHY standard is presented, which is capable to acquire for highly reliable water quality information in the wide outdoor areas for effective water quality management of small water quality facilities is distributed in the long distance and remote areas. Previously, Long distance transmission is difficult in most water quality sensor module is using RS-485 protocol. But with this system, even in harsh outdoor environment, it is possible to establish a radio wave sensor in a wide area network, and not only water quality sensor shall be connected to the wireless system, but also wireless integrated management system shall provide more effective way of management of the numerous small water supply facilities spread throughout the community, so that the administrator can remotely monitor the data of water turbidity, pH, residual chlorine in the water-supply, water-level, and generate alarm to cope with risks. The management of small water facilities is done by residents will be very effective to notice water quality information of small water facilities to residents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.251-259
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• 2014

In this paper, we propose Low Energy Service Discovery (LESD) protocol for common discovery mode of IEEE 802.15.8 Peer Aware Communications (PAC). In order to minimize power consumption, Basic Repetition Block (BRB) is defined. Device is able to select operating mode and synchronize other devices through it. Proposed MAC procedure is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) based on overhearing technique. Even if device has not been received response signal since transmitted request signal, it is able to discover other devices of same group through the overhearing technique. IEEE 802.15.8 PAC has required that performances of common discovery mode are presented about discovered devices during the simulation time, discovery latency and average power consumption. By considering the number of devices per group and channel environment, two scenarios are evaluated through system level simulation and the simulation results of proposed scheme are compared with CSMA/CA in same simulation conditions. As a result, proposed scheme is able to get high energy efficiency of devices as well as increase the number of discovered devices during simulation time when the longer the number of devices is distributed over a limited area.