• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.64-69
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• 2007

This paper designs an interpolator for a high speed ultra wide bandwidth (UWB). The UWB wireless technology will play a key role in short-range wireless connectivity supporting very high bit rates availability, low power consumption, and location capabilities. Because the UWB needs high operating speed, a cubic interpolator based on variable parameters for the UWB needs to be operated at a high speed. In order to improve an operating speed, the modified cubic interpolator is based on both a parallel processing and a pipelining in the existing interpolator simultaneously. Experimental results show that a maximum operating speed and period of the proposed interpolator using Stratix II EP2S60F1020C3 is 102.42MHz and 9.764ns, respectively. Compared to the conventional interpolator, the designed cubic parameter interpolator has been improved more than about 190%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.7
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• pp.1792-1801
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• 2012

Symbol timing error amounts to a major degradation in the system performance. Conventionally, timing error is estimated by predefined preamble on both transmitter and receiver. The maximum of the correlation result is considered the start of the OFDM symbol. Problem arises when the prime path is not the strongest one. In this paper, we propose a new combined time and channel estimation method for multi-band OFDM ultra wide-band (MB-OFDM UWB) systems. It is assumed that a coarse timing has been obtained at a stage before the proposed scheme. Based on the coarse timing, search interval is set (or time candidates). Exploiting channel statistics that are assumed to be known by the receiver, we derive a maximum a posteriori estimate (MAP) of the channel impulse response. Based on this estimate, we discern for the timing error. Timing estimation performance is compared with the least squares (LS) channel estimate in terms of mean squared error (MSE). It is shown that the proposed timing scheme is lower in MSE than the LS method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.669-676
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• 2003

In this paper, a novel design method for an ultra-wide band TEM horn antenna is proposed on the basis of parallel plate waveguide theory. A principle of TEM modes generation is analyzed and the characteristics of this antenna are experimentally investigated. The proposed TEM horn antenna has an exponentially tapered structure to increase matching bandwidth. Also, the designed TEM horn has shortened length but increased aperture so that the bandwidth for cutoff frequency is increased. The measured result show that the proposed TEM hem antenna has the frequency band of 75 MHz to 1200 MHz for VSWR less than 2.0 and the bandwidth of the TEM horn becomes more than twice comparing to that of a linearly tapered TEM hem. It is anticipated that the manufactured antenna is applicable to UWB systems for impulse response measurement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.968-975
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• 2006

Research about the mode of MIMO that can get a coding benefit at the same time with a diversity benefit using a multiple antenna at the fading channel for a high-speed data transmission have been processed actively But the analysis about the interference of UWB system comes not to consist yet. So this paper analyzed the performance of the interference of UWB system to SFBC-OFDM and SFTC-OFDM system that applied a space block code which has a space diversity characteristic to OFDM system at MIMO channel. We shelved the performance that SFTC-OFDM system is robuster than SFBC-OFDM system under MB-OFDM UWB Interference.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.83-89
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• 2010

This paper presents the impacts of Ultra Wide-Band(UWB) sensor using frequency of 4.5 GHz on Broadband Wireless communication system which uses frequency of 4.5 GHz. The Minimum Coupling Loss (MCL) method and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) is used to evaluate the interference effects of UWB sensor on Broadband Wireless communication system, respectively. The minimum protection distance between single UWB sensor and mobile station of Broadband Wireless communication system should be more than 1.2 m to guarantee the co-existence. In case of multiple UWB sensors, UWB transmitting PSD of around -68.5 dBm/MHz below should be required to guarantee interference probability of 5% below for mobile station of Broadband Wireless communication system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.267-268
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• 2008

This paper presents compact low frequency ultra-wide band(UWB) sensor design and studying of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with new designed UWB sensor. In this study, we designed new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both low frequency and high frequency band of partial discharge signal. And experiments of offline PD testing on in medium voltage (22.9kV) underground cable and mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative test, the calibration signal injection test provided with conventional IEC 60270 method and high voltage injection testing are included.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.121-129
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• 2008

This paper presents the spatial multiplexing MIMO system to increase data rate to double in MB-OFDM UWB system, which is ECMA standards, and compares BER performance of various receiver structures. The complexity and BER performance of various types of spatial multiplexing receivers are compared and analyzed using diagonal and horizontal encoding techniques for $2{\times}2$\;and\;2{\times}3$ antennas systems. Computer simulations exhibit that $2{\times}2$ MML and $2{\times}3$ ZF method show better BER performance than that of SISO system with simple complexity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.985-988
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• 2005

The international standards of high-rate WPAN (Wireless Personal Area network) are under development by IEEE802.15 WPAN TG3 (Task Group 3). The study area of TG3 mainly consists of three parts: high rate physical and media access control layer in 2.4GHz ISM (Industrial Scientific Medical) non licensed frequency band; an alternative high rate physical layer by using UWB (Ultra Wide Band); and another alternative high rate physical layer based on millimeter wave. This paper describes the standardization trends of UWB and millimeter wave.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6264-6269
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• 2014

This study examined the state of the UWB frequency band of foreign policy for application to domestic findings. The results confirmed that the UWB frequency can be prescribed mainly for use in a communication service area, unlike foreign countries, such as the United States and Europe for the current technology standard. On the other hand, the expansion of the UWB service area to various fields may appear as interference in the domestic industry protection and enable these rules. Therefore, the UWB frequency should be used in other areas except for broadcast and communication, if the output meets the specified criteria, as in the case of a foreign country. This is thought to be helpful for protecting the domestic industry and activated services.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.1
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• pp.28-35
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• 2007

This paper presents a high-speed flash analog-to-digital converter (ADC) for ultra wide band (UWB) receivers. In this flash ADC, the interpolating technique is adopted to reduce the number of the amplifiers and a linear and wide-bandwidth interpolating amplifier is presented. For this ADC, the transistor size for the cascaded stages is inversely scaled to improve the trade-off in bandwidth and power consumption. The active inductor peaking technique is also employed in the pre-amplifiers of comparators and the track-and-hold circuit to enhance the bandwidth. Furthermore, a digital-to-analog converter (DAC) is embedded for the sake of measurements. This chip has been fabricated in $0.13{\mu}m$ 1P8M CMOS process and the total power consumption is 113mW with 1V supply voltage. The ADC achieves 4-bit effective number of bits (ENOB) for input signal of 200MHz at 5-GSample/sec.