• ETRI Journal
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• v.29 no.6
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• pp.716-724
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• 2007

As ultra-wideband impulse radio (UWB-IR) uses short-duration impulse signals of nanoseconds, even a small number of timing errors can cause a detrimental effect on system performance. A delay-locked loop (DLL) is proposed to synchronize and reduce timing errors. The design of the DLL is vital for UWB systems. In this paper, an improved DLL is introduced to a UWB-IR time-hopping spread-spectrum system. Instead of using only two central correlator branches as in a conventional DLL, the proposed system uses two additional correlator branches with different delay parameters and different weight parameters. The performance of the proposed schemes with the optimal parameters is compared with that of traditional schemes through simulation: the proposed four-branch DLLs achieves less tracking jitter or a longer mean time to lose lock (MTLL) than the conventional two-branch DLLs if proper parameters are chosen.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.385-390
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• 2011

In this paper, various ultra-wideband (UWB) spatial multiplxing (SM) multiple input multiple output (MIMO) receivers based on a prerake diversity combining scheme are discussed and their performance is analyzed. Several UWB MIMO detection approaches such as zero forcing (ZF), minimum mean square error (MMSE), ordered successive interference cancellation (OSIC), sorted QR decomposition (SQRD), and maximum likelihood (ML) are considered in order to cope with inter-channel interference. The UWB SM systems based on transmitter-side multipath preprocessing and receiver-side MIMO detection can either boost the transmission data rate or offer significant diversity gain and improved BER performance. The error performance and complexity of linear and nonlinear detection algorithms are comparatively studied on a lognormal multipath fading channel.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1471-1475
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• 2007

In this paper, a novel embedded ultra wideband (UWB) band-pass filter is presented on a FR-4 package substrate including high Dk resin coated copper (${\varepsilon}_r=30$) film. The proposed UWB filter is comprised of a parallel resonator with meander-type uniform impedance resonator (UIR) and two series resonators with high Q circular stacked spiral inductor and metal-insulator-metal (MIM) capacitor. In order to obtain excellent attenuation characteristics by generating attenuation poles in lower and upper stop bands, a single MIM capacitor is added to each resonator. The fabricated FR-4 embedded UWB filter has insertion loss of -1.0dB and return loss of -11dB, respectively. It has also extremely wide bandwidth (over 50%) and small size ($3.7{\times}4{\times}0.77\;mm^3$) which is compatible with LTCC devices.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.482-484
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• 2006

This paper describes fast-hopping frequency synthesizers for multi-band OFDM(MB-OFDM) ultra-wide band(UWB) systems. Three different structures in generating 3 center frequencies(3432MHz, 3960MHz, 4488MHz) are designed and compared. The first structure generates 3 center frequencies using only one PLL operating at 4224MHz. The second uses three PLLs operating at corresponding center frequencies. The third employes two PLLs operating at 3960MHz and 528MHz. Simulation results using a 0.18um RF CMOS process parameters show that the third structure exhibit the best characteristics. The band switching time of the proposed synthesizer is less than 1.3ns and the spur is less than -36dBc. The synthesizer consumes 22mA from a 1.8V supply.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.6 s.336
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• pp.61-66
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• 2005

In this paper, we implemented a impulse generator, the one of the part in UWB(Ultra Wide Band) system using step recovery diode(SRD) and gain-switced semiconductor laser. The impulse generator was consisted of four stages; The first stage used SRD to generate the first impulse for gain switching. The second stage controled current for the suitable gain switching condition. The third was the second impulse generator to generate gaussian pulse. For gain switching, the first impulse was applied to semiconductor laser. In the last stage the gain switched impulse was converted into mono-gaussian pulse. The measured mono-gaussian pulse was 360 psec pulse-width and $-70mV \~ +50mV$ amplitude in time domain. In frequency domain its magnitude and bandwidth was, respectively, -41dBm and 3.6GHz. Accordingly, the impulse generator that we suggested was suitable for UWB systems.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2021-2022
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• 2006

Power-Line Communication (PLC)는 전력선을 채널로 이용한 통신 방법으로 별도의 전용선 설치 없이 통신이 가능한 기술을 말한다. 그러기에 오래전부터 연구가 진행되어 왔으며 최근에도 여전히 고속 전력선 통신에 관한 연구가 진행 중에 있다. 이에 본 논문에서는 이런 고속 전송을 위해 최근 연구가 활발한 고속 Ultra Wide Band (UWB) 전송기술을 전력선 통신에 적용하여 시뮬레이션한 후 결과를 통해 적용가능성을 확인한다.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.27-30
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• 2003

무선 통신 서비스에 대한 수요가 급격히 증가하면서 높은 데이터 전송율을 갖는 무선 통신에 대한 연구가 활발히 진행되고 있다. UWB는 (Ultra Wide Band) 이러한 문제점을 해결할 수 있는 통신 방법 중의 하나로 이 논문에서는 현재 IEEE 802.15.TG3a 표준화 위원회에서 제시하고 있는 채널 모델에 대해서 알아보고, 제시된 채널 모델에 LS (Least Square) 방법을 적용하여 채널의 임펄스 응답을 (Channel Impulse Response) 추정한다. 채널 추정의 성능 지표로 Preamble의 크기에 따른 MSE와 (Mean Square Error) 각각의 채널에 대한 비트 에러율을 사용하여 모의 실험을 본 논문에서 다루는 추정 기법의 성능을 분석한다.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.250-253
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• 2003

In this paper, a characteristics and points of Guassian pulse using UWB system is analyzed, the TDMG pulse is proposed that originated ultra wide band signal without pulse width reduction. It is showed that TDMG pulse character compare with Gaussian pulse through computer simulation. And it is verified that decreased a interference of other communication systems

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2123-2125
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• 2005

Ultra wide band electromagnetic energy can be transmitted to a far field by emitting the nanoseconds high voltage Pulse electromagnetic energy via an antenna. This UWB EM energy is expected to be used in post-packing pasteurization of food, detection of buried objects or underground water veins and caves and the treatment of waste water or polluted gas. The nanoseconds pulse forming for UWB generation using 500kV blumlein line and an ultrafast switch is mentioned.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1464-1474
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• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.