• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.133-134
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• 2006

In this paper the platform system for IEEE 802.15.4 Low Rate WPAN is designed and fabricated. IEEE 802.15.4 Low Rate WPAN system serves the functions and realization of home-area network. According to the IEEE 802.15.4 standard, there are two modes, One is BPSK modulation in 868/915MHz frequency band. The other is O-QPSK modulation in 2.45GHz frequency band. In this paper we implemented the platform system mounted in one PCB board in 868/915MHz frequency band of IEEE 802.15.4 Low Rate WPAN system. We measured that the platform system which consists of digital part and RF part has good performance. Also RF part is realized by design and fabrication of the RF transceiver IC. The key issue is to make the platform system which provides the function of Low Rate WPAN system to meet the requirement of IEEE 802.15.4 standards.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.667-670
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• 2004

In this paper, we have presented the improved IF transceiver architecture and the implementation and experimental results on re-configurable transceiver based on digital IF for multiple wideband OFDM/TDD base stations for high-speed portable internet-service in which is issued Korea. The implemented IF transceiver has been designed to support multiple frequency allocations and multiple standards by only modifying the programmable software not its hardware like as the software-defined-radio concept. Also, the digital complex quadrature modulation technique has been used for the digital IF transmitter, which is able to combine multiple frequency bands in digital processing block not RF block and to reject the image frequency signals. And the bandpass sampling technique has been used for the digital IF receiver to reduce the sampling rate of ADC. This paper has shown the experiment results on the frequency response and constellation on the base-station implemented using the modified IEEE 802.16a/e physical layer channel structure based on OFDM/TDD.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.4
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• pp.23-31
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• 2018

This paper presented the implementation and design of the 2T-2R wireless HD video streaming systems over 1.7 GHz frequency band using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system used USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transmitted from USRP RIO up or down converts to 1.7 GHz by using self-designed 1.7 GHz RF transceiver modules and it is finally communicated HD video data through self-designed 2x9 sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express x4 to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 32 dBc and to transmit and receive HD video in experiment environment anywhere. The proposed hybrid beam forming system could be used not only in the future 5G mobile communication systems under 6 GHz frequency band but also in the systems over 6 GHz frequency band like ones in mmWave frequency bands.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.28-35
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• 2022

Interference always exists between wireless communication systems used in the same frequency band or adjacent frequency bands. In order to deploy a new wireless communication system such as a 5G system, a new frequency band must be allocated to the system. For this purpose, after analyzing interference between the existing system and the new system, a method of setting a frequency guard band or a minimum separation distance has been used as a passive method to limit the interference effect. This paper presents a wideband RF IRM(Interference Reduction Module) that can actively reduce the influence of interference between wireless communication systems. The wideband RF IRM can reduce the interference effects of 5G signals on satellite signals. The principle and structure of the wideband RF IRM are presented. The wideband RF IRM can suppress approximately 20dB of interference signal in 100MHz bandwidth when only interference signal exists. It also shows that when a 5G interference signal of -45dBm/100MHz and a satellite signal of -55dBm/40MHz exist simultaneously at a center frequency of 3.83GHz, about 15dB of 5G interference signal can be reduced in the frequency range covered by the satellite signal. The experimental results demonstrate that the wideband RF IRM can actively reduce the 5G interference signal on the satellite signal and can be used for the purpose of reducing the interference effect in a similar environment.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.435-435
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• 2004

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.885-892
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• 2013

The main advantage of ESPAR antenna is that ESPAR antenna requires only a single RF chain for reduction of transceiver's hardware complexity, as compared to conventional MIMO system. In conventional MIMO system, each data symbol is mapped to each antenna. But, each data symbol is mapped to each orthogonal basis pattern in ESPAR antenna system. In this paper, we design beamspace MIMO system using ESPAR antenna with single RF chain for MIMO system of low-complexity and low power consumption. And then, we analyze performance of beamspace MIMO according to each PSK modulation. Performance of beamspace MIMO system is similar to performance of conventional MIMO system. As a result of analyzing the performance of beamspace MIMO system using higher-order PSK modulation. we can confirm that performance characteristic of beamspace MIMO system with low complexity and low power consumption is similar to digital communication of signal domain.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.339-342
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• 2005

In order to support ultrawide-band signal generation for low rate WPAN, several types of signal generation mechanisms are suggested such as Chaos, Impluse, and Chirp signals by the activity of IEEE 802.15.4a. The communication system applied chaos theory may have ultrawide-band characteristics with spread spectrum and immunity from multipath effect. In order to use the advantage of chaotic signal generation, we introduce the system implementation of communication and networking systems with the chaos UWB signal. This system may be composed of mainly three parts in hardware architecture : RF transmission with chaotic signal generation, signal receiver using amplifiers and filters, and 8051 & FPGA unit. The most difficult part is to implement the chaotic signal generator and build transceiver with it. The implementation of the system is devidced into two parts i.e. RF blocks and digital blocks with amplifiers, filters, ADC, 8051 processor, and FPGA. In this paper, we introduce the system block diagram for chaotic communications. Mainly the RF block is important for the system to have good performance based on the chaotic signal generator. And the main control board functions for controlling RF blocks, processing Tx and Rx data, and networking in MAC layer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.66-79
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• 2005

In this paper, we have performed the analysis of RF transceiver system and communication link for the improvement in reliability of Smart-UAV(Unmanned Aerial Vehicles) Data-Link. The system analysis performed using the development specification of the data link and data sheet of using components through the system simulation tool that is Agilent EEsof ADS. Also, the communication link analysis peformed using a variety of propagation models for the smart UAV operation environments. As a result, we have presented problems appeared in the simulation results and development specification. As well as, we have presented about several problems and consideration issue for system design through the communication link analysis.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.153-154
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• 2007

In this paper, we propose context information communication system using RF module to prevent railway cross accident. Since the communication module transmits to the train with high bit rate, OFDM(Orthogonal frequency division multiplexing) modulation method that distributes high speed data and transmits multiple times is applied. And image information is transmitted to the train's transceiver device by using ISM band (2.4GHz frequency band) that is proper to mobile communication. By using this system, we can deal with urgent situations at the railway cross and prevent railway cross accidents in advance.