• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.293-296
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• 2003

This paper evaluates the RF transmitting parameters of User Equipment(UE) for W-CDMA system based on 3GPP specifications. The parameters of transmitter are derived from the aspect of RF. In order to keep UE in high performance, the transmitter requirements such as ACLR, EVM, Peak Code Domain Error, spectrum emission mask are considered. The UE transceiver is implemented on the basis of performance requirements and then tested for the analysis of RF transmitter characteristics through test scenarios.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.194-201
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• 2015

A frequency modulated ultra-wideband (FM-UWB) transmitter with a high-robust relaxation oscillator for subcarrier generation and a dual-path Ring VCO for RF FM is proposed, featuring low power and low complexity. A prototype 3.65-4.25 GHz FM-UWB transceiver employing the presented transmitter is fabricated in $0.18{\mu}m$ CMOS for short-range wireless data transmission. Experimental results show a bit error rate (BER) of $10^{-6}$ at a data rate of 12.5 kb/s with a communication distance of 60 cm is achieved and the power dissipation of 4.3 mW for the proposed transmitter is observed from a 1.8 V supply.

• 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.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.17-20
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• 2001

In this paper, we realized a transceiver system for short distance communication with a commercial RF module working in ISM band. Also we measured system performance by transmitting baseband data in a building and then we compared the demodulated data bits with stored data bits in a PC connected with demodulator. The RF module In the experiments works only in the bandwidth of 424MHz-429MHz. The signal level degrades as the distance between transmitter and receiver increases. We measured the signal level and bit error and present the measured results with various locations in the building. And it is concluded that the measured data may be used in the design of short distance network in a building.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.1
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• pp.11-24
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• 2022

Open Radio Access Network (O-RAN) standard has been proposed to separate the baseband signal processing unit from the Radio Frequency (RF) unit at base station system mainly for reducing the cost of base station systems through open-source interfaces between the two units. To satisfy the performance metrics in various scenarios, several fronthaul functional split options were presented by O-RAN. Amongst these options, the split option 7-2x is widely adopted in practical applications due to its excellent trade-off between the required bandwidth and RU overhead. In this paper, we present a hardware implementation of a base station system that is compliant with the Category B of O-RAN split option 7-2x. It consists of O-DU and O-RU implemented with a commercial off-the-shelf Digital Signal Processor and RF transceiver, respectively. The performance of the proposed base station system is evaluated in terms of Bit Error Rate and received signal power as well as the required fronthaul bandwidth. Through various experimental tests, we have observed that the proposed system reduces the fronthaul bandwidth nearly by 89.7% compared to the conventional system that dose not employ the O-RAN standard.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.445-453
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• 2016

This paper presents the implementation and design of the 1T-1R wireless HD video streaming systems over 28 GHz mmWave frequency using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system uses USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transceived from USRP RIO up or down converts to 28 GHz by using self-designed 28 GHz RF transceiver modules and it is finally communicated HD video data through self-designed $4{\times}8$ sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express ${\times}4$ to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 25.85 dBc and to transceive HD video in experiment environment anywhere.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.6
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• pp.47-54
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• 2008

In this paper, interference analysis has been performed between RF receiver and transmitters on each soldier for Multiple Integrated Laser Engagement System(MILES) which are following ZigBee standard. In order to obtain minimum transmit power without interference, 1% Packet Error Rates(PER) from 14 transmitters attached on a soldier to a receiver are measured with the scenarios for simple transmitting and receiving network configuration and for repeating network configuration. Based on this transmit power, the available distance for interference free among soldiers is simulated using Spectrum Engineering Advanced Monte Carlo Analysis Tool(SEAMCAT). Later scenario gives the benefit of 10dB lower transmit power, smaller and lighter power source, and better activity of trainee.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.558-565
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• 2013

In this paper, modeling and simulation for performance analysis of high resolution SAR system has been carried out in the time, frequency and numeric domain using ADS Ptolemy simulation tool of Agilent corporation. SAR system consists of antenna, controller and transceiver. Error parameters affecting SAR system performances have been defined, modeled and simulated such as phase noise of frequency synthesizer, amplitude and phase characteristic of TWTA, sampling frequency of waveform generator and I/Q imbalance. Finally, the development requirements of SAR system based on the impulse response function have been derived.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1146-1153
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• 2007

In this paper, we analyze the I/Q imbalances effects at the WiBro uplimk when using direct-conversion RF transceiver. If I/Q imbalance exists, the transmit signal is spread over two sbcarriers. As a result, phenomenon of performance reducing is produced. Contrary to OFDM system in which one user uses all subcarrier, symmetrical two subcarriers are assigned other users in OFDMA system. I/Q imbalances elements can't be estimated such a conventional allocation method of tiles in subchannel and compensated. In order to solve the problem, We propose a new method in order that symmetrical two subcarriers are assigned one user. If novel method is applied, we can estimate I/Q imbalances and compensate distortion received signal. As a result, we can obtain a performance similar performance when I/Q imbalances is not existed. Also, if proper detection methods are used, we get the effect of performance improvement, because of diversity gain what is happened due to combining I/Q imbalances with multi path fading channel.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.81-86
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• 2020

Ambient backscatter communication has a drawback in which the transmission power is limited because the data is transmitted using the ambient RF signal. In order to improve transmission efficiency between transceiver, a channel estimator capable of estimating channel state at a receiver is needed. In this paper, we consider the K-means algorithm to improve the performance of the channel estimator based on EM algorithm. The simulation uses MSE as a performance parameter to verify the performance of the proposed channel estimator. The initial value setting through K-means shows improved performance compared to the channel estimation method using the general EM algorithm.