• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.65-71
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• 2022

In this paper, we propose an opportunistic data relay scheme in narrowband multihop combat radio networks. Narrowband networks have physical restrictions on high-speed transmission. Furthermore, the topology changes dynamically due to the jamming of the enemy, signal interference between friendly forces, and movement of network entities. Therefore, the traditional relay scheme that collects topology information and calculates a relay path before transmission is unsuitable for such networks. Our proposed scheme does not collect topology information and transmits data opportunistically. The scheme can cause unnecessary data relaying that is not related to data delivery to the destination node. However, for small networks, the effect of increasing network throughput by not gathering topology information is much greater than the effect of reducing throughput by unnecessary data relays. We demonstrate the performance superiority of the proposed scheme through simulation in the worst case of network topology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.582-596
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• 2019

Considering that the existing Long Term Evolution is not suitable for the fast and frequent handovers of high-speed trains, this paper proposes a relay-assisted handover mechanism to solve the problems of long handover authentication time and vulnerable to security attacks. It can achieve mutual authentication for train-ground wireless communication, and data transmission is consistent with one-time pad at the same time. The security analysis, efficiency analysis and simulation results show that the proposed mechanism not only realizes the forward security and resists many common attacks, but also effectively reduces the computational overhead of train antenna during the secure handover process. When the running speed of a train is lower than 500km/h, the handover delay is generally lower than 50ms and the handover outage probability is less than 1.8%. When the running speed of a train is 350km/h, the throughput is higher than 16.4mbps in the process of handover. Therefore, the secure handover mechanism can improve the handover performance of high-speed trains.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1553-1558
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• 2000

The development of recent computer and communication technology has changed Automation System using communication network, and the new USB substituted with Serial Communication is already developed and now popular. In this paper, High speed data transfer system design using USB interface and communication application simulated for the situation is introduced. Base on USB, we can use additive function efficiently coped with former field device. The 'Winsock Connection USB Ternimal,' designed for hardware simulation, control the field device connected by USB, and provide the way for remote control of field device by Telnet connection through TCP/IP. That theorem can guarantee controlling direct input dta of user, and acuate function of field device using USB Packet Transmission. As a result of amy research, this communication application system identified good operation of field device with those of former field device. Another result of the experiment of hardware operation, we obtained accomplishment that the sufficient bandwidth guarantee of USB has high speed and high performance, and reduce the occupancy of system.

• IE interfaces
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• v.14 no.2
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• pp.148-157
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• 2001

This paper considers a network restoration algorithm for all-optical WDM networks. As the increasing traffic and transmission speed, any failure on the networks will lead to loss of huge data and disruption of the services. Therefore, a network restoration algorithm is necessary for the high-speed all-optical networks. This paper suggests a distributed restoration algorithm for line or channel level failures under the dynamic rerouting. For the algorithm, some measures for performance evaluation are explicitly derived and simulation studies are exploited to evaluate its usability by SLAM(Simulation Language for Alternative Modeling) II.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.152-156
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• 2009

This paper examines the BER performance of the recently proposed half-symbol-rate-carrier (HSRC) offset quadrature phase-shift-keying (OQPSK) receiver for high-speed data communication. A modified demodulation technique using a bit-time period signal integration, the bit-error-rate (BER) performance of the HSRC-OQPSK signal improves more than 4dB compared to that of a demodulation technique using a symbol-time period integration. This paper also examines the BER performance of modified demodulation with various band-limited channels modeled using low-pass filters, and the three different data-rate systems are simulated and compared with the performance of the system using the conventional demodulation technique.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.56-62
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• 2004

We present a multi-Gbit/s digital I/O interface based on RF-modulation and capacitive-coupling over an impedance matched transmission line. The RF-interconnect(RFI) can greatly reduce the digital switching noise and eliminate the dc power dissipation over the channel. It also enables reduced signal amplitude(as low as 200 ㎷) with enhanced data rate and affordable circuit overhead. This paper addresses the system advantages and implementation issues of RFI. A prototype on-chip RFI transceiver is implemented in 0.18-${\mu}{\textrm}{m}$ CMOS. It demonstrates a maximum data rate of 2.2 Gbit/s via 10.5-㎓ RF-modulation. The RFI can be very instrumental for future high-speed inter- and intra-ULSI data links.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.25-31
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• 2004

fireless LAN can offer high data rate communication between wireless terminals. In IEEE 802.11 wireless LAN, a basic service unit is called a Basic Service Set (BSS), which consists of one AP and more than one wireless terminals. Terminals far from the AP may not communicate with high data rate because signal strength is weakened as they move away from the AP. In this paper we propose a method to permit high speed data transmission by grouping terminals and by using part of wireless terminals as repeaters. We analyze the proposed and algorithm via simulations. Our proposed grouping mechanism is shown to be an effective way to increase the distance for high rate transmission.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.103-109
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• 2018

One of the 5G goals is provide to high data rates for users moving at high speeds, such as trains. High mobility scenarios such as high speed train (HST) scenarios are expected to be typical scenarios for fifth generation communication systems. As the HST develops rapidly, it is necessary to transmit wireless communication data to train passengers, and the communication speed required by users is gradually increasing. HST users require high network capacity and stable communication services regardless of the location or speed of the HST communication system. Therefore, a transmission frame is constructed for the 5G mobile communication system in the mm band to be used for the fifth generation mobile communication, the HST communication system is implemented, and the performance of the wideband non-stationary MIMO HST channel is analyzed in the HST scenario.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.9-14
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• 2008

Intentional city bands and public radio frequencies could reduce the internet transmission speed on the wired lines because AM and HF band are overlapping on the xDSL up and down data steam by way of the wired transmission lines. We were designed the adaptive common mode rejection circuit with 2 way amplifier against public radio frequency. Specially our circuits were applied for power and signal lines. We could reduced the common mode rejection up to 30dB and increased the up stream speed around 1.8 times using a our developed equipments. Also it could expanded the transmission distance up to 1.7 times than old lines.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.4
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• pp.450-456
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• 2010

In the high-speed packet service, next generation mobile communication system has emerged as a major feature. If the fire of these high-speed kit services and non-continuous transmission of data due to the symmetrical nature of daeyiteo traffic for D-CDMA system has been actively studied. Small amounts of data moving in the uplink, but the real-time video downlink transmission, such as downloading large files to move data and services to those with asymmetric traffic characteristics, a system that can efficiently handle the data requirements be. Of 3GPP TDD(Time Division Duplex) scheme based on CDMA and TDMA in a way by introducing the concept through the proper allocation of time slots that can handle asymmetric traffic efficiently, has an advantage. TD-CDMA system by considering the characteristics of the frame configuration of transmission methods, such as physical channel structure and channel coding has been investigated. In addition, the HARQ scheme TD-CDMA system performance is analyzed by comparing them.