• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.79-82
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• 2000

In this paper, the performance of 05-CDMA system with smart antenna is analyzed for different bandwidths (1.25MHz, 5MHz) and different channel environments (rural, urban). For the analysis of smart antenna system, the vector channel having the spatio-temporal correlation is modeled as a time-variant linear filter in time, and each multipath is assumed as a reflective wave from only one direction (only one cluster) in space. Several multipaths within one chip are distinguished into each one and the strongest signal is selected. DS-CDMA system with smart antenna using wider bandwidth present better performance than that using narrow bandwidth. It is shown that the smart antenna is more effective in urban area when using 2D-RAKE receiver.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.77-84
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• 2012

This paper introduces our development of a MIMO-OTA system with simplified configuration. The key element of our proposal is the adoption of an antenna branch-controlled configuration for generating multipath delayed waves. The signal processing is carried out on IF band signal with an FPGA in a fading-emulator-type MIMO-OTA measurement system. The proposed scheme is largely different from available system configurations for the fading simulator method of constructing the OTA test environment. We describe the principle of the proposed scheme, channel model incorporated in the system, basic configuration of the developed system, and its performance.

• International journal of advanced smart convergence
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• v.1 no.1
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• pp.27-33
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• 2012

In this paper, we analyze and simulate performance of space time block coded (STBC) binary pulse amplitude modulation-direct sequence (BPAM-DS) ultra-wideband (UWB) systems with double binary turbo code in indoor environments for various ubiquitous healthcare (u-healthcare) applications. Indoor wireless channel is modeled as a modified Saleh and Valenzuela (SV) model proposed as a UWB indoor channel model by the IEEE 802.15.SG3a in July 2003. In the STBC encoding process, an Alamouti algorithm for real-valued signals is employed because UWB signals have the type of real signal constellation. It is assumed that the transmitter has knowledge about channel state information. From simulation results, it is shown that the STBC scheme does not have an influence on improving bit error probability performance of the BPAM-DS UWB systems. It is also confirmed that the results of this paper can be applicable for u-healthcare applications.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.217-220
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• 2001

Turbo codes of long block sizes have been known to show very good performance in an AWGN channel and the turbo code has been strongly recommended as error correction code for IMT-2000 in 3GPP(3$^{rd}$ Ceneration Partnership Project). Recently, turbo codes of short block sizes suitable for real time communication systems have attracted a lot of attention. Thus in this paper we consider the turbo code of 1/3 code rate and short frame size of 192 bits in ITU-R channel model. We analyzed the performance of W-CDMA systems of 10MHz bandwidths employing RAKE receiver with not only MRC diversity but also turbo code..

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1689-1692
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• 2002

In this paper, the performance of DS-CDMA system with smart antenna is analyzed for different bandwidths (1.25MHz, 5MHz) and different channel environments (rural, urban). For the analysis of smart antenna system, the vector channel having the spatio-temporal correlation is modeled as a time- variant linear filter in time, and each multipath is assumed as a reflective wave from only one direction (only one cluster) in space. Several multipaths within one chip are distinguished into each one and the strongest signal is selected. DS-CDMA system with smart antenna using wider bandwidth present better performance than that using narrow bandwidth. It is shown that the smart antenna is more effective in urban area when using 2D-RAKE receiver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.34-43
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• 2007

In the IEEE 802.15.3 Medium Access Control (MAC) protocol, Simultaneously Operating Piconets (SOPs) are linked by the parent/child (P/C) or parent/neighbor (P/N) configuration, which work on a Time Division Multiple Access (TDMA) basis. This provides interference mitigation but the overall throughput is limited because the SOPs share the channel time exclusively. The protocol is not efficient for SOPs if we focus on the combination of interference mitigation and high throughput maintenance. In this paper Public Channel Time Allocation (Public CTA) is proposed, which is able to greatly reduce the inter-piconet interference (IPI) and achieve greater throughput without much loss of link success probability (LSP) in the SOPs. The simulation results based on the SOPs of Direct Sequence Ultra Wideband (DS-UWB) system demonstrate that the proposed scheme effectively supports the coexistence of SOPs, and it can not only significantly improve the overall throughput of SOPs but also maintain high LSP.

• ETRI Journal
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• v.34 no.6
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• pp.858-868
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• 2012

In this paper, stochastic models for the cross-correlation of multiple channels are established based on measurement data collected using a wideband multiple-input multiple-output relay Band Exploration and Channel Sounder system at 3.7 GHz. We propose models for the cross-correlation characteristics of large-scale parameters (LSPs) between two links, that is, the base station and mobile station (MS) link and the relay station and MS link. The LSPs include shadow fading, Rician K-factor, delay spread, angle spread of arrival, and angle spread of departure. Furthermore, models are established for the cross-correlation of the small-scale fading in the impulse responses of two links. The statistics of these model parameters are investigated as functions of geometrical features of the multilink. They are extracted from a large amount of cross-correlation observations, which are obtained in three measurement sites along more than one hundred measurement routes. These models can be used together with the standard single-link channel models for the generation of correlated components, for example, path clusters, in two separate channels.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.53-65
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• 2012

Recently wireless intra-vehicle communication has received a great interest from the automotive industry and ultra wideband (UWB) technology is considered as one of the potential candidate for this system. Many research works have been done on the measurement and modeling of intra-vehicle communication channel. However, very little work has been reported for the performance analysis of various PHY layer methods under the intra-vehicle communication environment. This paper is to study IEEE 802.15.4a standard in intra-vehicle channel and to evaluate its performance. Channel model in chassis and engine compartment is considered for evaluation. Through simulation BER performance of system with different receiver structures is analyzed.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.25-28
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• 2000

In this paper, we assume various number of multipaths in one chip duration according to spreading bandwidth. And we take into account of the effects of autocorrelation and relative phases among multipath components within one chip duration, and analyze fading effects. We derive the average error probability for different number of users. Then, we compare the performance of W-CDMA systems with different bandwidths. From the simulation results for different band-widths, wideband CDMA systems show better performance than narrowband CDMA systems in vehicular and pedestrian environments.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.553-556
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• 2003

In this paper was studied the improvements and increasements of the data transmission rate in UWB (Ultra wideband) systems. so Considered that previous UWB systems of code structure and proposed the New constructure that was synthesized the PPM and Bi-Phase Modulation structure, may increase the data transmission rate of multiple channel structure using Time-slots. This proposed structure was modeled suitable at Home Networking conditions and was simulated. and so measure the performance of coding construction, and compare that New synthesized structure with early structure. so we can verify the superiority of New experiment.