• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.181-186
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• 2017

IEC 61850 is a standard for power utility automation. Using IEC 61850 that uses ethernet may consume more costs for the automation than its value in small distribution substations. Thus, less expense and installation cost are required for the automation of small distribution substations. This study used inexpensive and easy-to-install IEEE 802.15.4 and implemented a bridge between IEC 61850 and IEEE 802.15.4, using Raspberry Pi to connect the existing IEC 61850. Using IEEE 1588, IEC 61850 traffic performances were evaluated, such as SV, GOOSE and MMS. Analyzing IEC 61850 requirements and performance evaluation results, the scope of application of IEEE 802.15.4 was decided.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.115-121
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• 2017

Times New RomanThe utilization of Information and Communication Technologies (ICT) in the smart grid application can construct efficient and reliable electrical grid. IEC 61850 was adopted as the standard for smart grid exchanging the information required in an electric power utility. However, applying technologies like IEC 61850 using Ethernet to the automation of small distribution substation directly may cost more than the value of the small distribution substation itself. IEEE 802.15.4 technology attracts attention in the field of power utility automation because of low installation cost and ease of installation. Studies are conducted, which use IEEE 802.15.4 in less strict D1 small distribution substation. This study applied IEEE 802.15.4 to the small distribution substation and conducted performance evaluation using the actual equipment. This study determined the scope of application of IEEE 802.15.4 by conducting a comparative analysis of the message type in IEC 61850.

• Information and Communications Magazine
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• v.25 no.2
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• pp.11-17
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• 2008

최근 IT-BT-NT 융합의 대표적인 기술이며, wearable computing이나 healthcare와 같은 대표적인 응용분야를 포함하는 WBAN (Wireless Body Area Network)에 대해 IEEE 802.15.6 TG BAN을 중심으로 물리계층, 데이터 링크 계층, 네트워크 계층 및 응용 계층 등에 대해서 표준화가 진행되고 있다. IEEE 802.15 WG는 2006년 11월에 Wireless Medical BAN IG를 SG로 승인하였으며, 2007년 11월, 제51차 IEEE 802 WPAN 본회의에서 TG BAN으로 최종 승격하였다. 따라서, 본고에서는 IEEE 802.15.6 TG BAN을 중심으로 WBAN 국내외 표준화 활동에 대해 고찰하고자 한다.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.4 no.2
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• pp.9-17
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• 2005

Coexistence of different wireless systems that share the 2.4 GHz ISM frequency band is becoming one of the most important issue. This paper presents a model of the interference that IEEE 802.11b affected by IEEE 802.15.4. The packet error rate (PER) of IEEE 802.11b under the interference of IEEE 802.15.4 is analyzed. The PER is obtained by using the bit error rate (BER) and the collision time. Further, this paper suggests a packet length to reduce the effect of the IEEE 802.15.4 interference and obtain a maximum throughput of the IEEE 802.11b. The analytical results are validated using simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.43-49
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• 2017

In this paper, we propose the scheduling scheme of IEEE802.15.4e TSCH which is not specified in standard specification. The proposed scheme schedules the link by cooperating among the devices. A new device scans EBs(Enhanced Beacons) from network. An advertiser device broadcasts an enhanced beacon frame including links information on allocated channel offset and time-slots, and a new device can determine its own channel offset and time-slot. It's performance on maximum throughput and minimum delay is evaluated by comparing the proposed approach with a typical single channel IEEE802.15.4.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.837-846
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• 2013

Recently, new technologies based on wireless LAN is being studied because utilization on smart phone using Wi-Fi is increased. 802.11 b/g/a is universalized wireless LAN technologies based on ISM, the standard developed in 11's working group of IEEE 802. standardization about IEEE 802.11ac that overcame limitation on Blue-ray of IEEE 802.11n or uncompressed video transmission and IEEE 802.af's technologies using TVWS is being actively studied. In this paper, ability of transmission considering the security on AP operated by these technologies have measured and done a comparative analysis with existing wireless LAN environment ability of transmission measured when appling security is more stable than existing ability of transmission in an environment with obstacles and shorten of transmission time is confirmed as a result of analysis.

• The KIPS Transactions:PartC
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• v.17C no.6
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• pp.485-490
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• 2010

IEEE 802.11n supports two frame aggregation schemes, aggregation for MAC service data unit (A-MSDU) and aggregation for MAC protocol data unit (A-MPDU), to improve throughput at the MAC layer. In this paper, we propose a cooperative frame aggregation (CoFA), which can recover erroneous frames in a cooperative manner based on A-MPDU. Specifically, CoFA receive multiple frames from direct and relay paths, and combined multiple frames jointly. Numerical results show that CoFA outperforms direct transmission and relay transmission over diverse channel conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.75-80
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• 2005

In this paper, 2-stage power amplifier has been designed for 5.8GHz wireless LAN application. The power amplifier PldB output power has 21.6dBm at 5.8GHz frequency. Also the power amplifier shows 17.6dB gain and -17.8dB input return loss at 5.725GHz to 5.825GHz. The OFDM modulation and transmission block have been modeled in order to analyse the relationship between the power amplifier distortion and output ACPR for the IEEE 802.11a wireless LAN. The nonlinear characteristic of the power amplifier has been modeled as AM-to-AM and AM-to-PM using the behavioral model, and the output spectrum is analysed with the phase distortion variation. Also, amplifier back-off value from PldB to satisfy the required IEEE 802.11a standard spectrum mask has been simulated with phase distortion, and the simulation data have been compared to the measurement result collected by using the pre-distortion technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.640-647
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• 2006

This paper describes a design of AES-based CCMP(Counter mode with CBC-MAC Protocol) core for IEEE 802.11i wireless LAN security. To maximize the performance of CCMP core, two AES cores are used, one is the counter mode for data confidentiality and the other is the CBC node for authentication and data integrity. The S-box that requires the largest hardware in ARS core is implemented using composite field arithmetic, and the gate count is reduced by about 27% compared with conventional LUT(Lookup Table)-based design. The CCMP core was verified using Excalibur SoC kit, and a MPW chip is fabricated using a 0.35-um CMOS standard cell technology. The test results show that all the function of the fabricated chip works correctly. The CCMP processor has 17,000 gates, and the estimated throughput is about 353-Mbps at 116-MHz@3.3V, satisfying 54-Mbps data rate of the IEEE 802.11a and 802.11g specifications.

• Journal of Korea Multimedia Society
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• v.9 no.7
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• pp.844-853
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• 2006

The IEEE 802.17 Resilient Packet Ring (RPR) for future Local, Metropolitan, and Wide Area Networks was recently standardized, but it still suffer from delay jitter deterioration and even some bandwidth loss under unbalanced overload. In order to overcome these drawbacks, this paper proposes a bandwidth redistribution based fairness control method, compatible with the legacy one, in which each congested node measures the amount of available bandwidth of its bottleneck link resulted from regulating upstream nodes' shares of the link bandwidth, calculates optimal fair rate with the number of uptream nodes requiring more bandwidth, and then redistributes the available bandwidth to the upstream nodes by advertising the rate. The performance evaluation results show that the proposed method fairly redistributes 95% of the bottleneck link bandwidth with even only two redistributions.