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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Advanced Navigation Technology
Journal Basic Information
Journal DOI :
The Korea Navigation Institute
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Dec 2002
Volume 6, Issue 3 - Nov 2002
Volume 6, Issue 2 - Aug 2002
Volume 6, Issue 1 - Jun 2002
Selecting the target year
A Study on the MAC Protocol to Reduce the Delay Time in Aeronautical Mobile Communication
Kim, Yong Joong ; Kang, Seok Yub ; Lim, Hyeong Yeol ; Park, Hyo Dal ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 1~9
Analysis on the Interference Effects of Radio-Relay Stations into HAPS System
Kim, Bong-Seok ; Park, Sang-Jun ; Ham, Hyung-Il ; Kang, Young-Heung ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 10~16
High altitude platform station(HAPS) is being developed actively in some countries as well as Korea. At the same time Resolution 734 was adopted in WRC-2000 to study the sharing of HAPS into the existing fixed services in the bands above 3GHz. As one of the sharing studies, interferences between HAPS and radio-relay stations should be analyzed by dividing into two cases, the one is the interference effects of HAPS system into radio-relay stations and on the contrary, the other that of radio-relay stations into HAPS system. Since the former case had been already studied, only the latter case will be focused on this paper. Analysis result shows that the coordination distance must be needed above 100 km when the trendline of radio-relay is located vertical to HAPS service area and the transmitting power is -50 dBW/MHz.
Performance Evaluation of Multi-User Detectors Employing Subtractive Interference Cancellation Schemes for a DS-CDMA System
Seo, Jung-Wook ; Kim, Young-Chul ; Oh, Chang-Heon ; Ko, Bong-Jin ; Cho, Sung-Joon ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 17~26
In this paper, we have analyzed the BER (Bit Error Rate) performance of multi-user detectors employing SIC(Successive Interference Cancellation) and PIC (Parallel Interference Cancellation) which are the representative schemes in the subtractive interference cancellation. We have considered the MUD structure employing HIC (Hybrid Interference Cancellation) which combines SIC with PIC scheme, and then analyzed the BER performance. We have evaluated the BER performance of SIC and HIC schemes which execute the soft decision to generate the tentative data bit for the purpose of the interference cancellation in MAI and noise environments. Through the numerical analysis and computer simulation, it is shown that HIC can remove the effect of MAI more efficiently than the others, that improve the BER performance and increase the capacity of DS-CDMA systems regardless of the power control conditions. The reason is that the SIC scheme in front of HIC can solve the near-far problem caused by the imperfect power control and PIC scheme in the rear of it can improve the performance much more.
Distance Detection between Vehicles Using Stereo Vision
Yang, Seok-Joo ; Baek, Joong-Hwan ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 27~36
As the number of autonomous vehicles is increased, drivers are trending toward constant interests in detecting distance between vehicles in close-range and maintaining the distance between forward and backward vehicles for drivers' safety. In this paper, we propose a method of detecting the distance between two vehicles by computing the disparity of the close-rang vehicle using stereo vision. The boundary of the vehicle is obtained by using the modified wavelet transform which has multi-resolution characteristics. Then the disparity between left and right images is computed using coarse-to-fine method and histogram matching. Here we transform the left-right stereo images through 3-steps using the modified wavelet for maintaining the original resolution. An experimental result showed that the proposed method had 4.65% in total error rate.
The Performance Evaluation and Analysis of Next Generation Wireless LAN with OFDM
Han, Kyung-Su ; Youn, Hee-Sang ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 37~43
This paper describes the performance evaluation and analysis of Wireless Local Area Network (W-LAN) in the 5 GHz ISM-band in compliance with IEEE 802.11a. At present, most W-LAN products are based on 2.4 GHz band, but low speed (11Mbps) has the limitation to serve systems demanding high-speed data transmission. To solve this problem, it is necessary to design next generation W-LAN system with 54Mbps in the 5GHz. It is sure that implementation of next generation W-LAN will bring competitive advantages. In particular, it will support telecommunications for high-speed mobile environments as well as for fixed places such as a school zone, a lecture room, a hospital and other premises. A few simulation methods are applied to more accurate and reliable performance analysis of next generation W-LAN. To verify if continuous data service is supported for a high-speed mobile notebook, multi-path fading channels between wireless Access Point (AP) and wireless Network Interface Card (NIC) are modeled. In addition, low interference is analyzed via convolutional codes and Orthogonal Frequency-Division Multiplexing (OFDM). Also, to obtain reliable Bit Error Rate (BER), a single tap Least Mean Square (LMS) equalizer is applied. Given the above simulation, next generation W-LAN is an ideal solution for continuous data transmission in high-speed mobile environments.
The Performance Analysis of Equalizer for Next Generation W-LAN with OFDM System
Han, Kyung-Su ; Youn, Hee-Sang ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 44~51
This paper describes the performance evaluation and analysis of an Orthogonal Frequency-Division Multiplexing (OFDM) system having the least Inter Symbol Interference (ISI) in a multi-path fading channel environment. Wireless Local Area Network (W-LAN) in accordance with IEEE 802.11a and IEEE 802.11b provides high-speed transmission to universities, businesses and other various places. In addition, service providers can offer a public W-LAN service on restricted areas such as a subway. The proliferation of W-LAN has led to greater W-LAN service demands, but problems are also on the rise in offering a good W-LAN service. In particular, urban areas with high radio wave interference and many buildings are vulnerable to deteriorated QoS including disconnected data and errors. For example, when high-speed data is transmitted in such areas, the relatively high frequency generates ISI between Access Points (AP) and Mobile Terminals (such as a notebook computer), leading to a frequency selective fading channel environment. Consequently, it is difficult to expect a goodW-LAN service. The simulation proves that the OFDM system enables W-LAN to implement QoS in high-speed data transmission in a multi-path fading channel environment. The enhanced OFDM performance with 52 sub-carriers is verified via data modulation methods such as BPSK, QPSK and 16QAM based on IEEE 802.11a and punched convolutional codes with code rate of 1/2 and 3/4 and constraint length of 7. Especially, the simulation finds that the OFDM system has better performance and there is no data disconnection even in a mobile environment by applying a single tap equalizer and a decision feedback equalizer to a mobile channel environment with heavy fading influence. Given the above result, the OFDM system is an ideal solution to guarantee QoS of the W-LAN service in a high-speed mobile environment.
Design and Realization of 20 GHz Push-Push FET Dielectric Resonator Oscillator
Jung, Jae Kwon ; Kim, Ihn Seok ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 52~62
Electrical characteristics of two types of 20 GHz Push-Push GaAs MESFET dielectric resonator oscillators having Wilkinson and T-junction power combiners for the output stage have been investigated. The Push-Push oscillator for suppressing fundamental frequency 10 GHz and enhancing 20 GHz has been designed and realized in microstrip configuration on 20 mil thick RT-Duroid(
=2.52) teflon substrate. Two different types of power combiners, T-junction and Wilkinson, have been considered. Whenever one type of the combiners has been adopted for the output circuit, output power, phase noise and fundamental frequency suppression characteristics of the oscillator have been measured. When the Wilkinson power combiner was used, a maximum output power of 5.67 dBm, a phase noise of -105.5 dBc/Hz at an offset frequency of 100 kHz and a fundamental frequency suppression of -29.33 dBc have been measured. When the T-junction power combiner was used, a maximum output power of -1.17 dBm, a phase noise of -102.2 dBc/Hz at an offset frequency of 100 kHz and a fundamental frequency suppression of -17.84 dBc have been measured.
A Study on a Radio System for Lifesaving in Case of a Falling Accident of the Sea
Choi, Byung-Ha ; Kim, Gu-Chol ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 62~68
Mother ship must be able to know accident occurrence information rapidly to rescue crew who fall in sea. In this paper, designed and manufactured transceiver of prescribed 447 MHz is operating as low power radio station specified in Radio Regulation. So, it is available without special permission proceedings getting form probation so that the use of this system may be easy. the system has been started for operation when the sensor get in touch with water. The system transmits with modulation by 500Hz square wave, and the receiver alarms when the transmitted signal is received. Therefore, the system can be used for not only saving a life, but also for low speed of data transmission below 2,400 bps, and other purposes.
Performance Analysis of WAP Packet Considering WTP SAR Algorithm and RLP in Wireless CDMA Network
Moon, Il-Young ; Roh, Jae-Sung ; Cho, Sung-Joon ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 69~76
With the growth of data communication service by mobile devices, WAP is proposed to efficiently access the Internet contents by user request through wireless condition that has a high error rate and mobility. But, because a transmission speed of WAP is limited, it takes many times to transmit and to receive the data. This paper has studied the WAP packet transmission time using WTP-SAR algorithm. As a method that is to improve transfer capability of WAP, using SAR function in WTP, total message down from upper layer has been fragmented and packet is transmitted through RLP frame time slot. Then, we have analyzed the transmission time of WAP packet with variable RLP layer size on the wireless CDMA network for next generation systems. From the results, we could obtain the WAP packet transmission time and optimal WTP packet size.
Packet Performance Simulation of ACL/SCO Link in Bluetooth Piconet
Kim, Do-Gyun ; Roh, Jae-Sung ; Cho, Sung-Eon ; Cho, Sung-Joon ; Kim, Jung-Sun ;
The Journal of Advanced Navigation Technology, volume 6, issue 1, 2002, Pages 77~83
The emergence of Bluetooth as a radio interface scheme has allowed electronic devices to be instantly interconnected as ad-hoc networks. These short range ad-hoc wireless networks are called piconets, operated in the unlicensed 2.45 GHz ISM(Industrial, Scientific, Medical) band where up to eight devices may be used to configure single or overlapping piconets. In this paper, we have simulated the PER(Packet Error Rate), the ratio of received packet and payload BER(Bit Error Rate) of piconet with packet types of Bluetooth ACL/SCO(Asynchronous Connection Less/Synchronous Connection Oriented) link over wireless ad-hoc environment. The Rayleigh fading effects are considered as channel model, and the simulation results are based on the baseband model of Bluetooth specification. From the simulation results, the PER and the throughput of Bluetooth piconet are sensibly affected by the packet type of ACL/SCO link.