• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.23-28
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• 2021

In recent years, research on smart factory wireless mobile communication technology that wirelessly remotely controls utilities is being actively conducted. The Wi-SUN(Wireless Smart Utility Network) Alliance proposed Wi-SUN protocol structure suitable for building a platform such as a smart factory as a new wireless communication standardization standard based on EEE802.15.4g/e. It analyzes the performance of the IEEE802.15.4e CSL(Coordinated Sampled Listening) Mode MAC(Media Access Control) in terms of latency and looks at considerations for efficient operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9B
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• pp.811-820
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• 2006

In this paper, The correlation of the power consumption of sensor node is analyzed according to the analyze parameter in IEEE 802.15.4 star sensor network. And It is studied the influence on analysis parameter. The power consumption of sensor network in transmission process and average transmission power consumption drives to numerical formula. And CSEM WiseNET system measurement value is used. As a simulation result, The power consumption of sensor node in star network consist of 10 sensor nodes is more than 20 % that in single network in average. When beacon signal interval is 0.1 second in all frequency bands, the power consumption of sensor node in up-link is more than 2.5 times that in down-link in average. When beacon signal interval is 1 second and the number of sensor nodes increases to 100 and sensing data increases to 100 byte, the power consumption of sensor node increases to 2.3 times. And The superior performance of 2.4 GHz frequency band has than 868/915 MHz frequency band up to $6{\sim}12$ times.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.319-325
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• 2015

Remarkable advances in wireless communication technology have enabled communications among people who are far away from each other. In recent, the needs of local area voice communication using a wireless system based on low-cost and simple hardware are rapidly rising. However, since these applications require that the multi-users communicate on the same wireless channel in a small area, the existing voice technologies are not suitable for directly applying to these applications. Therefore, in this paper I propose a novel idea enabling multi-user voice communication. In particular, as a short range wireless solution, I employ the IEEE 802.15.4 based on low power and low cost. However, since originally the standard is not developed for voice communication, we extend the original scheme to be suitable for the voice communication by utilizing the extended concept of GTS. The capacity and validity of the proposed scheme are evaluated through quantitative analysis in various voice compression rates.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.37-42
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• 2012

In this paper, we analyze the maximum allowable transmitting output level of transmitter, which meets the required interference probability, in order to get the method that different communication systems can be existed and used simultaneously in adjacent channels. We analyze the performance result according to various density of interfering transmitter and transmitter output in hetero systems. In order to get the relationship with between density of interfering transmitter and transmitter output, we consider WiBro as an interfering transmitter, WLAN as a victim receiver and Extended Hata and IEEE 802.11 model as a channel environment respectively. Analyzed coexistence results may be widely applied into the technique developed to get the coexisting condition for wireless devices using many communication protocols in same frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.154-160
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• 2005

Microwave Otters are essential device in modem wireless systems. A compact dimension BPF(Band-pass Filter) for IEEE 802.11a WLAN service is realized using LTCC multi-layer process. To extrude 2-stage band-pass equivalent circuit, band-pass and J-inverter transform applied to Chebyshev low-pass prototype filter. Because parallel L-C resonator is complicate and hard to control the inductor characteristics in high frequency, the shorted $\lambda/4$ stripline is selected for the resonator structure. The passive element is located in the different layers connected by conventional via structure and isolated by inner GND. The dimension of fabricated stacked band-pass filter which is composed of six layers, is $2.51\times2.27\times1.02\;mm^3$. The measured filter characteristics show the insertion loss of -2.25 dB, half-power bandwidth of 220 MHz, attenuation at 5.7 GHz of -32.25 dB and group delay of 0.9 ns at 5.25 GHz.

• Journal of IKEEE
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• v.19 no.3
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• pp.400-406
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• 2015

In this paper, we designed a decision feedback based diversity modem hardware architecture for IEEE802.11p WAVE and tested the modem on the road with car attached shark antenna. One of the dual channel modem and the diversity single modem with maximum ratio combining algorithm can be selected on the designed architecture. The designed modem have been implemented on the Xillinx Kintex7 FPGA. We tested the modem performance on the smart highway experience road. As experimental results, we can verify the performance of the diversity modem on real road and the enlarged communication range by more than 100%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.849-852
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• 2007

In this paper, the high gain and the broadband microstrip patch antenna, which is applicable to 5 GHz band wireless LAN, is designed in order to integrate IEEE 802.11a's detailed standards($a:5.15{\sim}5.25$, $b:5.25{\sim}5.35$, $c:5.725{\sim}5.875$ [GHz]). Designed patch antenna has settled resonance frequency by insert substance(polyurethane: ${\varepsilon}_r=6.5$) between the separated parasitic patch and radiation patch for the purpose of miniaturize. And the form (${\varepsilon}_r=1.03$) were to fix the separated radiation patch and ground plans by air. Designed frequency bandwidth(VSWR 2:1) of the antenna showed broadband characteristic of $4.9[GHz]{\sim}6.1[GHz]$ to about 1.2[GHz]. Also the E-plan and H-plan profit 12[dBi] above, the 3[dB] beamwidth showed the characteristic over the E-plan $30^{\circ}$ and H-plan $60^{\circ}$ to be improved.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.249-253
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• 2010

Resource of wireless frequency bandwidth is gradually going to be deficient due to explosive increase of traffic and saturated non-licensed frequency band such as ISM. In the contrary, many licensed frequency bands are revealed to be low in utilization by several measurement based researches. To alleviate this inefficiency, a concept of cognitive radio is suggested. Cognitive radio lets non-licensed user exploit the licensed frequency band as long as non-licensed user does not interfere licensed user and as a result, it is possible to harness wireless frequency more efficiently. IEEE 802.22 is the first standard network with cognitive radio technology and it employs Two-Stage channel sensing mechanism to accomplish both enough licensed user protection and efficient channel utilization. In this paper, we analyze the overhead of Two-Stage channel sensing mechanism and identify the influence of channel sensing time to the overhead.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.117-126
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• 2009

Wireless mesh networks (WMNs) consist of mesh routers and mesh clients, where mesh routers have minimal mobility and form the backbone of WMNs. They provide network access for both mesh and conventional clients. The integration of WMNs with other networks such as the Internet, cellular, IEEE 802.11, IEEE 802.15, IEEE 802.16, sensor networks, etc., This paper presents a secure and efficient authentication mechanism for Wireless mesh network. The validity of proposed mechanism is provided by BAN logic and the efficiency of suggested mechanism is showed through the performance evaluation.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.281-288
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• 2010

This paper investigates the performance of IEEE 802.11p wireless access in vehicular environments (WAVE) system in small-scale fading models reported by Georgia Institute of Technology (Georgia Tech). We redesign the small-scale fading models to be applied to the computer simulation and develop the IEEE 802.11p WAVE physical layer simulator to provide the bit error rate and packet error rate performances. Moreover, a new channel estimator using decision directed channel estimation and linear minimum mean square error smoothing is proposed in order to improve the performance of the conventional least square channel estimator using two identical long training symbols. The simulation results are satisfactorily coincident with the scenarios of Georgia Tech report, and the proposed channel estimator significantly outperforms the conventional channel estimator.