• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.5C
• /
• pp.326-335
• /
• 2011

In this paper, we evaluate the performance of multi-antenna techniques adopted for the IEEE 802.16m standard. Base station is equipped with 4 or 8 antennas, and each mobile station (MS) has 2, 4, 8 antennas. The number of MSs is 4, and MIMO modes 0, 1, and 4 are evaluated. For each mimo mode, various number of data streams can be implemented, and the selected number of streams in the paper corresponds to the parameters adopted for hardware implementation. The error performance of various mimo modes presented in this paper was used as reference performance to verify successful hardware implementation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.5A
• /
• pp.394-401
• /
• 2007

MIMO transmission systems can have various transmission modes, which result from the various combinations of the antenna diversity with spatial multiplexing. In this paper, we find the optimal mode to maximize the capacity with the BER constraint and the optimal selection (diversity transmission or spatial multiplexing transmission) for transmission of each transmission antenna, if necessary. The computer simulation results show that the proposed scheme has more capacity than the conventional scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.2
• /
• pp.33-48
• /
• 2018

In this paper, we characterise the joint interference alignment and power allocation strategies for a K-user multicell multiple-input multiple-output (MIMO) Gaussian interference channel. We consider a MIMO interference channel with a blind interference alignment through staggered antenna switching on the receiver. We explore the power allocation and the feasibility condition for cooperative cell-edge (CE) mobile users (MUs) by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy) and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern), and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired and interference signals to cancel the common interference signals, since the received signal must have a corresponding independent signal subspace. The sum capacity for a K-user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised.

• Journal of Advanced Navigation Technology
• /
• v.14 no.2
• /
• pp.220-226
• /
• 2010

In this paper, an low power symbol detector is proposed for MIMO communication system with two transmit and two receive antennas. The proposed symbol detector can support both the spatial multiplexing (SM) mode and spatial diversity (SD) mode for MIMO transmission technique, and shows the optimal maximum likelihood (ML) performance. Also, by sharing the hardware block and using the dedicated clock MIMO modes, the power of the proposed architecture is dramatically decreased. The proposed symbol detector was designed in hardware description language (HDL) and synthesized to logic gates using a $0.13-{\mu}m$ CMOS standard cell library. The power consumption was estimated by using Synopsys Power CompilerTM, which is reduced by maximum 85%, compared with the conventional architecture.

• Journal of Advanced Navigation Technology
• /
• v.14 no.3
• /
• pp.328-335
• /
• 2010

In this paper, an efficient algorithm and area-efficient hardware architecture have been proposed for $2{\times}2$ MIMO-OFDM based WLAN baseband modem with two transmit and two receive antennas. To enhance the performance of the receiver, the efficient timing synchronization algorithm and symbol detector based on MML algorithm are presented. Also, by sharing the hardware block with multi-stage pipeline structure and using the complex multiplier based on polar-coordinate, the complexity of the proposed architecture is dramatically decreased. The proposed area-efficient hardware design was designed in hardware description language (HDL) and synthesized to gate-level circuits using 0.13um CMOS standard cell library. As a result, the complexity of the proposed modem receiver is reduced by 56% over the conventional architecture.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.10
• /
• pp.817-820
• /
• 2018

In this letter, a compact multiple-input multiple-output(MIMO) antenna design for a 2.4 GHz wireless local area network(WLAN) band is proposed for use in smart glasses. To miniaturize the MIMO antenna system, a ground plane is employed within the antenna and a T-shaped ground is proposed. To achieve wideband isolation, dual resonance is formed by the ground mode. One resonance is created by the T-shaped ground and the second resonance is created by adding a slot and a capacitor between the two feed lines. The measurements show that the reflection coefficient characteristic was less than -5.1 dB, whereas the isolation obtained was less than -20 dB. The diversity performance was evaluated using the measured two-dimensional radiation patterns, and the envelope correlation coefficient(ECC) values achieved in the target band(2.4~2.5 GHz) were less than 0.1.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.10
• /
• pp.26-33
• /
• 2014

The spatial correlation (SC) for a multipath environment based on a $2{\times}2$ MIMO system are computed on the observation planes in the Rayleigh/Rician fading channels inside a mode stirred chamber. The correlation coefficients were obtained and compared for different distances and orthogonal polarization between two transmit antennas. The proposed method is useful for quantifying the potential diversity gain in antenna diversity systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.4
• /
• pp.349-356
• /
• 2015

In this paper, MIMO antenna with low correlation for LTE band 5(824~894 MHz) was designed by adopting monopole antenna and slot antenna. Based on ground characteristic mode theory, MIMO antenna was designed using different types of antennas for enhancement of correlation. MIMO antenna using PIFA and slot type antennas is proposed and correlation coefficient was compared with MIMO antenna using two PIFAs. Average correlation coefficient of MIMO antenna using two PIFAs was 0.71 but the proposed MIMO antenna had very low correlation coefficient of 0.17.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.6
• /
• pp.464-472
• /
• 2018

Future spaceborne satellite synthetic aperture radar(SAR) system is expected to acquire high-resolution images over wide swath areas. Conventional SAR systems suffer from ambiguity problems in both azimuth and range directions that lead to image quality degradation. Recently, multiple input multiple output(MIMO) SAR techniques having multiple orthogonal waveforms are proposed to overcome the conventional ambiguity problems in wide-swath imaging modes. In this paper, noisy orthogonal frequency division multiplex(OFDM) waveforms are developed to reduce the ambiguity problems and suppress the image quality degradation. SAR simulations are performed to evaluate the performance of the proposed technique for wide-swath SAR imaging.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.3
• /
• pp.41-50
• /
• 2010

In this paper, an area-efficient symbol detector is proposed for MIMO communication systems with two transmit and two receive antennas. The proposed symbol detector can support both the spatial multiplexing mode and spatial diversity mode for MIMO transmission technique, and shows the optimal maximum likelihood (ML) performance. Also, by sharing the hardware block with multi-stage pipeline structure and using the complex multiplier based on polar-coordinate，the complexity of the proposed architecture is dramatically decreased. The proposed symbol detector was designed in hardware description language (HDL) and implemented with Xilinx Virtex-5 FPGA. With the proposed architecture, the number of logic slices for the proposed symbol detection is 52490 and the number of DSP48s (dedicated multiplier) is 52, which are reduced by 35.3% and 85.3%, respectively, compared with the conventional architecture.