• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.99-105
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• 2009

This paper suggests novel signal processing methods for optimal beamforming of smart antenna system in CDMA2000 mobile communication environments. This method utilize characteristics of the reverse pilot channel of CDMA2000 mobile communication systems, and applies them to improve the performance of an adaptive algorithm, which is used to a smart antenna system for beamforming. To perform the best beamforming, it is important to get an exact beamforming algorithm. This paper proposed an algorithm based on Laglange multiplier which has such an adaptive process, and also proposed the method to demodulate the received signal through array antenna using pilot channel in CDMA2000 environment. This paper analysed the enhanced performance of proposed algorithm in various signal environment through signal modeling of physical layer in CDMA2000 reverse link.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.53-60
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• 2011

In order to augment the robustness of OFDM system to Rayleigh multipath fading, there exist two smart antenna algorithms, namely, Pre-FFT smart antenna and Post-FFT smart antenna. After the mathematical modeling of both smart antenna algorithms, computer simulations have been carried to compare and analyze the performance of generalized eigen problem based Pre-FFT algorithm and the performance of Wiener solution based Post-FFT algorithm. It has been shown that the Post-FFT smart antenna far outperforms the Pre-FFT smart antenna due to the computational complexities. Especially it is so when the multipath signal arrives at beyond the guard interval and a rich co-channel interferer is introduced. Performance of a subcarrier clustering method proposed to lessen the computing load has been compared to that of a typical Wiener solution based Post-FFT smart antenna. Performance comparison between MRC(Maximum Ratio Combining) diversity based Post-FFT algorithm and typical Post-FFT algorithm has also been carried.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.323-330
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• 2007

Performance indicators such as output SNR, SIR, SINR for rectangular smart antennas in CDMA basestations have been derived. Simulations have been carried out to find the rectangular smart antenna performance while varying the input SNR, number of antenna elements, and the interferers' spatial distributions. Simplified Conjugate Gradient Method was chosen as the underlying beam forming algorithm. It has been shown that the performance of a rectangular smart antenna is similar to that of the linear one having the same number of elements when the interferers are randomly distributed over the whole azimuth angle range.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.749-752
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• 2001

It has been studied about smart antenna that track the beau according to the position of users, and improving the communication quality. In this paper, we designed the smart antenna algorithm for realtimeg and implemented that using CPLD. The algorithm structure has systolic array compatible with adaptive filters. The performances of the propose algorithm were evaluated via computer simulation. The used software was MAX+plus II which is made by Altera.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.689-692
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• 2003

In this paper, we propose an adaptive beamforming algorithm for array antenna. The proposed beamforming algorithm, based on Block LMS (Block - Least Mean Squares) algorithm, has a variable step size from coefficient update. This method shows some advantages that the convergence speed is fast and the calculation time can reduced using a block LMS algorithm from frequency domain. As the adaptive parameter approaches a stationary state, it could reduce the number of filter coefficient update with the help of various step size. In this paper we compared the efficiency of the proposed algorithm with a standard LMS algorithm which is a representative method of adaptive beamforming.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.283-286
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• 2003

This paper presents a novel signal processing method for optimal beamforming of smart antenna system in cdma2000 1X mobile communication environments. This method utilizes characteristics of the reverse pilot channel of cdma2000 1X mobile communication systems, and applies them to improve the performance of an adaptive algorithm, which is used to a smart antenna system for beamforming.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.313-316
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• 2001

This paper shows performance of smart antenna systems with various adaptive algorithms. Geometrically based single bounce elliptical model (GBSBEM) is generated and the SMR performance of various adaptive algorithms are analyzed. According to the SINR, the system capacity of each algorithm are calculated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.1-11
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• 2004

This paper presents an implementation of smart antenna system channel card that executes modulation/demodulation. Operations and performances of modules of implemented channel card is confirmed and field test of channel card shows the performance of smart antenna systems. Based on the analysis obtained from the field test in cdma2000 1x environments which contains multipath lading, it is confirmed that smart antenna system channel card provide exact beampattern to the DOA and performance of proposed channel card has better FER by 5∼8 times, compared to 2 antenna diversity system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.603-610
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• 2005

Beam-forming method based on the estimated channel information at the base station degrade the performance mismatching directional vector in case of systems which Frequency Division Duplex (FDD) center frequency of uplink and downlink are different. Also blind estimation technique which is to obtain directional vector of reverse link through received signal has disadvantage of hardware complexity increase. To solve these problems, in present paper, a smart antenna algorithm which is to improve the beam-forming complexity increase due to user number by appling the spatial fourier transform to be able to beam- forming toward a wanted direction through adjusting a obtained uplink weight function by estimating Angle-of-Arrival (AoA) to the competable form at the downlink is proposed. The proposed algorithm is integrated to the CDMA downlink transmitter and simulations are performed to confirm the performance as frame error rate at the receiver. As a result, the beam forming effect is confirmed and the performance gain with the proposed algorithm is comparable to ordinary smart antenna system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.4
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• pp.45-53
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• 2003

A new smart antenna receiver which incorporates the spatial fourier Transform and the maximal ratio combining(MRC) is proposed. By adapting the spatial fourier transform, the proposed method could separate the received signal into several spatial frequency components which correspond to the arrival angles of signal components, which means the beam focusing. By using the MRC, the proposed method could achieve the maximum signal to noise ratio for the signal of interest. The proposed algorithm is integrated to the CDMA reverse link receiver and simulations are performed to confirm the performance. As a result, the beam focusing effect is confirmed and the performance gain with the proposed algorithm is comparable to ordinary smart antenna receivers. The simulations are performed over the additive white gaussian noise (AWGN) environments and the results are obtained for the beam focusing capability according to the angle of arrival of a signal and the bit error performance improvement according to the number of combining branches in the MRC.