• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.1
• /
• pp.43-52
• /
• 2010

In this paper, the mobile-WiMAX (m-WiMAX) using the Smart antenna technique is implemented. Experiments are performed to compare Smart antenna system with conventional single antenna system. To implement the m-WiMAX smart antenna system there are many considerations, key issues of which are symbol time acquisition, beamforming, calibration. In the paper, symbol time acquisition, beamforming, calibration are implemented in WiMAX Smart antenna system and we verified that Smart antenna system is superior to single antenna system. The experimental results show 5.5 dB performance enhancement of implemented Smart antenna system in throughput compared with a single antenna system. The experimental result is almost same as theoretical result of 6 dB.

• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.49-52
• /
• 2001

A virtual antenna system is presented to increase the channel capacity of a smart antenna in cdma2000. Although a smart antenna system can increase channel capacity by forming a beam to a desired user direction, an increase of channel capacity is limited by the number of antenna elements. A virtual antenna is proposed to improve the channel capacity by increasing the degree of freedom. The results show that the proposed system has a larger channel capacity than a conventional smart antenna system for the same number of antenna elements.

• Composites Research
• /
• v.20 no.3
• /
• pp.25-30
• /
• 2007

This paper describes the basic design and fabrication of smart skin antenna for phased array applications. The smart skin phased array antenna, of which radiation pattern can be electrically steerable without mechanical rotation, has to meet the both mechanical and electrical performance. The smart skin antenna is a honeycomb sandwich structure to enhance the mechanical performance such as strength, weight and so on. The example of smart skin antenna integrated with radome is designed with the resonant frequency of 5 GHz, circular polarization, 2 by 2 subarray, and a coaxial probe-fed excitation. In addition, the performance of raw microstrip patch antenna uncovered radome is investigate. The fabricated smart skin antenna shows a reasonable performance with gain of 12.2 dBi and frequency bandwidth of 6.4 %.

• 한국정보통신설비학회:학술대회논문집
• /
• 2008.08a
• /
• pp.384-388
• /
• 2008

Multiple antenna technology, such as multiple input multiple output (MIMO), beamforming is one of the most promising technology for broadband wireless communication. In OFDM environment, we found that as the number of paths is increased, smart antenna system cannot fully exploit beamforming gain. In this paper, we propose a beamforming scheme and analyze the performance of the proposed beamforming scheme in WiBro smart antenna system. WiBro is an OFDMA-based multiple access service for wireless broadband multimedia environment. The proposed beamforming technique for WiBro smart antenna system can effectively improve the performance of the systems in multipath fading environment.

• Proceedings of the IEEK Conference
• /
• 2002.06a
• /
• pp.33-36
• /
• 2002

A new smart antenna scheme based on spatial FFT is proposed. By combining the output of spatial FFT, the proposed structure shows similar performance gain compared to ordinary smart antenna systems. Moreover. the proposed scheme could be easily integrated to general receiver without beam focusing module. The analysis and simulation results show that the performances of proposed scheme are comparable to ordinary smart antenna systems

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

• Proceedings of the IEEK Conference
• /
• 2000.06a
• /
• pp.193-196
• /
• 2000

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 model having the spatio-temporal correlation is needed. Hence, the channel 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. A simulation is carried out by dividing several multipaths within one chip into each one and searching the strongest signal. 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.

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

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

• ETRI Journal
• /
• v.26 no.6
• /
• pp.605-614
• /
• 2004

In this paper, we investigate array calibration algorithms to derive a further improved version for correcting antenna array errors and RF transceiver errors in CDMA smart antenna systems. The structure of a multi-channel RF transceiver with a digital calibration apparatus and its calibration techniques are presented, where we propose a new RF receiver calibration scheme to minimize interference of the calibration signal on the user signals. The calibration signal is injected into a multi-channel receiver through a calibration signal injector whose array response vector is controlled in order to have a low correlation with the antenna response vector of the receive signals. We suggest a model-based antenna array calibration to remove the antenna array errors including mutual coupling errors or to predict the element patterns from the array manifold measured at a small number of angles. Computer simulations and experiment results are shown to verify the calibration algorithms.