• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.976-978
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• 2013

In this paper, we address data transmission systems using multiple linear polarized antennas over pure line-of-sight (LoS) wireless channels. We investigate the impact of antenna angles from the perspective of both channel capacity and error performance. We show that the optimal angles from the two perspectives are different, and evaluate the performance of the two optimal angles.

• ETRI Journal
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• v.40 no.5
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• pp.570-581
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• 2018

This work analyzes the performance of implementable detectors for the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) technique under specific and realistic operation system conditions, including antenna correlation and array configuration. A time-domain channel model was used to evaluate the system performance under realistic communication channel and system scenarios, including different channel correlation, modulation order, and antenna array configurations. Several MIMO-OFDM detectors were analyzed for the purpose of achieving high performance combined with high capacity systems and manageable computational complexity. Numerical Monte Carlo simulations demonstrate the channel selectivity effect, while the impact of the number of antennas, adoption of linear against heuristic-based detection schemes, and the spatial correlation effect under linear and planar antenna arrays are analyzed in the MIMO-OFDM context.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.179-181
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• 2004

This study presents a cylindrical WLAN antenna for MIMO systems. Three typical inverted-F antennas, which have individual ground plane, are placed on the cylindrical rod. An optimum antenna is fabricated by theoretical prediction and numerical simulation. The proposed antenna here can operate in the 5GHz bands(IEEE 802.1la) and be adopted in small wireless communication systems.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.409-413
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• 2008

In this paper, we introduce a platform of advanced multiple antenna system based on orthogonal frequency-division multiplexing (OFDM). The advanced multiple antennas have beamforming gain using array antenna. In array antenna systems, received signal has phase delay caused distance of each antennas, therefore it should compensate with optimum weight vector which calculated by Lagrange algorithm. To implement the presented above procedures using Digital Signal Processor (DSP), we should fixed-point design. The performance of implemented platform is verified through MATLAB$^{(R)}$ simulations with various signal environments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.89-95
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• 2004

In this paper, we proposed a multiple meander strip monopole antenna. Using meander strip structure, we could broaden the impedance bandwidth and reduce the antenna height. The proposed antenna has broad bandwidth, from 2.9 ㎓ to 10.85 ㎓, for VSWR $\leq$ 2 and has vertically polarized omnidirectional conical beam radiation pattern, which is suitable for UWB wireless systems.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.1
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• pp.7-21
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• 2017

Multiple antenna techniques employed in fourth generation mobile communication systems are affected on their performance mostly by transmission environments and antenna configurations. The performance of the indoor LTE(Long-term Evolution) MIMO(multiple input multiple output) has been rigorously evaluated with considering various diversity transmission schemes and propagation conditions in the paper. Specifically, MAC TP(medium access control throughput) and LTE system parameters related to the MIMO technique are analyzed for several indoor propagation conditions. The performance comparison between multiple antenna diversity mode and single antenna mode has been derived as well. The results performed in the paper give the guideline on antenna configurations of polarization diversity in LTE 2×2 MIMO for various indoor channel environments, and possibly are exploited by network operators and antenna manufacturers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.8-16
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• 2012

Recent work has been shown that cognitive radio systems with multiple antenna at both transmitter and receiver are able to improve performance of secondary users. In such system, the main drawback is the increased complexity and raised cost as the number of antennas increase. It is desirable to apply antenna selection which select a subset of the available antennas so as to solve these problems. In this paper, we consider antenna selection method for cognitive radio systems in correlated channel from the IEEE 802.11n. For a multiple-input multiple-output(MIMO) system with more antennas at transmitter than the receiver, we select the same number of transmit antennas as that of receive antennas. The exhaustive search for optimal antenna becomes impractical. We present criterion for selecting subset in terms of projection of channel correlation vector to increase performance of secondary user with decreasing interference at primary user.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.422-436
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• 2020

In this paper, we investigate the impact of antenna correlation on secure transmission in a multi-eavesdropper single-input multiple-output (SIMO) system, where the receiver and eavesdroppers are equipped with correlated antennas. Based on the practical passive eavesdropping system, the new closed-form expressions of secrecy outage probability (SOP) and non-zero secrecy capacity probability are derived to explore the effect of antenna correlation on the system with multiple eavesdroppers. To further analyze the secrecy performance of the investigated system, we theoretically derive the expression of asymptotic SOP to clearly show the diversity order and array gain. Finally, Monte Carlo simulations verify the effectiveness of our theoretical results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5745-5758
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• 2017

In this paper, we develop a simple but very effective 4 by 4 Multiple-Input Multiple-Output (MIMO) antenna system for mobile phones consisting of different types of antennas to achieve low correlation property at the frequency ranges of 1710 to 2170 MHz, which covers wide LTE service bands, from band 1 to band 4. The proposed antenna system consists of two pair of antennas. Each pair consists of a planar inverted-F antenna (PIFA) and a coupling antenna which has the property of the loop. The use of two different antenna types of IFA and a coupling achieves high isolation. Proposed antenna system occupies relatively small area and positions at the four corners of a printed circuit board. The gap between the two antennas is 4 mm, in order to realize the good isolation performance. To evaluate the performance of our proposed antenna system, we perform various experiments. The proposed antenna shows a wide operating bandwidth greater than 460 MHz with isolation between the feeding ports higher than 17.5-dB. It also shows that the proposed antenna has low Envelop Correlation Coefficient (ECC) values smaller than 0.08 over the all desired frequency tuning ranges.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.2
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• pp.95-102
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• 2013

In this paper, we have studied the performance of the AOA (Angle of Arrival) in multi-antenna systems for LBS (Location Based Services) and we also analyzed the performance of the AOA in SISO (Single Input Single Output) in multipath environments and their differences. The adequacy of AOA positioning in new communication environments was determined. Currently used positioning methods in 3G communication environment has been developed based on SISO. However, the accuracy of SISO-based TOA (Time of Arrival), TDOA (Time Difference of Arrival), AOA positioning techniques degraded in multipath environments. The communication system will be changed and developed. According to enhanced positioning techniques are required. Using antenna characteristics and the phase difference between antennas of LTE-Advanced standard's key technique MIMO system AOA positioning, and SISO based AOA positioning performance were analyzed. We found that AOA technique potential for use based on Multiple antenna systems by computer simulations.