• The Journal of the Acoustical Society of Korea
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• 제12권1E호
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• pp.78-81
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• 1993

본 논문에서는 noncoherent 환경하에서 벡터적 접근 방식을 이용하여 선형 제한 조건을 갖는 협대역 빔형성기의 출력 SINR 식을 유도하였다.

• 한국통신학회논문지
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• 제32권3C호
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• pp.323-330
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• 2007

CDMA 셀룰라 망의 기지국에 이용될 수 있는 선형 스마트 안테나를 이차원으로 확장시켜 성능의 척도인 출력 신호대잡음비(Output SNR: Output Signal to Noise Ratio), 출력신호대간섭비(Output SIR: Output Signal to Interference Ratio), 출력신호대간섭잡음비(Output SINR: Output Signal to Interference plus Noise Ratio)를 도출 하였다 Beam forming algorithm 으로 SCGM(Simplified Conjugate Gradient Algorithm)을 설정하고 입력신호대 잡음비, antenna element 숫자, 간섭신호의 분포 등을 변화시키며 평면 스마트 안테나의 성능을 simulate 하였다. 간섭신호들의 방위각(Azimuth angle)이 -90도 에서 +90도 사이에서 고르게 분포할 때, 평면 스마트 안테나의 성능은 같은 숫자의 element를 갖는 선형 스마트 안테나의 성능에 근접함을 보였다.

• The Journal of the Acoustical Society of Korea
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• 제13권2E호
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• pp.14-19
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• 1994

본 논문에서는 벡터적 접근 방법을 이용하여 noncoherent 상황에서 선형 제한 조건을 갖는 광대역 빔 형성기의 출력 SINR식을 도출하였다. 여기서 입사되는 광대역 신호들은 평탄한 스펙트럼을 갖는다고 가정하였다.

• ETRI Journal
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• 제41권5호
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• pp.637-647
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• 2019

Separating highly correlated users can reduce the loss caused by spatial correlation (SC) in multiuser multiple-input multiple-output (MU-MIMO) systems. However, few accurate analyses of the loss caused by SC have been conducted. In this study, we define signal-to-interference-plus-noise ratio (SINR) loss to characterize it in multiuser multiple-input single-output (MU-MISO) systems, and use coefficient of correlation (CoC) to describe the SC between users. A formula is deduced to show the accurate relation between SINR loss and CoC. Based on this relation, we propose a user selection method that utilizes CoC to minimize the average SINR loss of users in massive MU-MISO systems. Simulation results verify the correctness of the relation and show that the proposed user selection method is very effective at reducing the loss caused by SC in massive MU-MISO systems.

• 대한전자공학회논문지TC
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• 제44권4호
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• pp.10-16
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• 2007

본 논문은 MMSE 수신기를 가지는 MIMO MC-CDMA시스템에서의 출력 SINR을 분석한다. 단일 안테나에서의 분석을 위한 가정들이 다중안테나에 바로 확장 적용되지 않기 때문에 단일 안테나를 가지는 MC-CDMA시스템에 대한 기존의 성능 분석은 MIMO MC-CDMA 시스템에 바로 적용하지 못한다. 그러므로 본 논문에서는 Marcenko Pastur law와 확장된 Haar 유니터리 행렬의 특성을 이용하여 MIMO system에 대한 성능 분석을 시도한다. 분석을 통해 확산 코드 길이가 무한대로 갈 때 출력 SINR이 특정값으로 접근함을 보이고 그 값을 freeness가정을 통해 구하여 비트 오차확률을 구하고 실험과 비교한다.

• Journal of Communications and Networks
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• 제16권1호
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• pp.1-9
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• 2014

Block diagonalization (BD) has been proposed as a simple and effective technique in multiuser multiple-input multiple-output (MU-MIMO) broadcast channels. However, when channel state information (CSI) knowledge is limited at the transmitter, the performance of the BD may be degraded because inter-user interference cannot be completely eliminated. In this paper, we propose an efficient CSI quantization technique for BD precoded systems with limited feedback where users supported by a base station are selected by dynamic scheduling. First, we express the received signal-to-interference-plus-noise ratio (SINR) when multiple data streams are transmitted to the user, and derive a lower bound expression of the expected received SINR at each user. Then, based on this measure, each user determines its quantized CSI feedback information which maximizes the derived expected SINR, which comprises both the channel direction and the amplitude information. From simulations, we confirm that the proposed SINR-based channel quantization scheme achieves a significant sum rate gain over the conventional method in practical MU-MIMO systems.

• Journal of Communications and Networks
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• 제10권2호
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• pp.163-174
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• 2008

Performance of downlink transmission strategies exploiting cooperative transmit diversity is investigated for distributed multiple-input single-output (MISO) systems, for which geographically distributed remote antennas (RA) in a cell can either communicate with distinct mobile stations (MS) or cooperate for a common MS. Statistical characteristics in terms of the signal-to-interference-plus-noise ratio (SINR) and the achievable capacity are analyzed for both cooperative and non-cooperative transmission schemes, and the preferred mode of operation for given channel conditions is presented using the analysis result. In particular, we determine an exact amount of the maximum achievable gain in capacity when RAs for signal transmission are selected based on the instantaneous channel condition, by deriving a general expression for the SINR of such antenna selection based transmission. For important special cases of selecting a single RA for non-cooperative transmission and selecting two RAs for cooperative transmission among three RAs surrounding the MS, closed-form formulas are presented for the SINR and capacity distributions.

• 한국전자통신학회논문지
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• 제9권2호
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• pp.195-202
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• 2014

다양한 상업적, 군사적 방면에서 사용되고 있는 위성항법시스템(Global Positioning System: GPS)은 특정 사용자나 물체의 위치를 추정하기 위해 설계되었다. 정확한 위치추정을 위해 위성항법시스템은 최소 네 개의 위성으로부터 신호를 수신하여야 한다. GPS 수신기는 매우 낮은 신호-대-잡음 비(signal-to-noise ratio: SNR)에서 동작하며, GPS 신호에 비해 매우 높은 전력을 가지는 간섭신호들에 의해 위치추정 성능에 영향을 받을 수 있다. 본 논문에서는 고 전력 간섭들을 정확한 GPS 신호의 도래각(angle-of-arrival: AOA) 정보 없이 제거하는 변형된 역확산기(modified despreader) 기반의 다수개의 GPS 신호를 위한 적응 간섭제거기를 소개한다. 또한 변형된 역환산 빔형성기의 출력에 대한 신호-대-간섭 및 잡음 비(signal-to-interference and noise ratio: SINR)의 수학적 해석을 제공한다. 컴퓨터 시뮬레이션을 통해 고려된 GPS 수신기의 간섭제거성능과 SINR에 대한 수학적 해석을 확인한다.

• ETRI Journal
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• 제36권1호
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• pp.62-68
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• 2014

This paper presents a novel user selection method based on the signal-to-interference-plus-noise ratio (SINR), which is approximated using limited feedback data at the base stations (BSs) of multiple user multiple-input multiple-output (MU-MIMO) systems. In the proposed system, the codebook vector index, the quantization error obtained from the correlation between the measured channel and the codebook vector, and the measured value of the largest singular value are fed back from each user to the BS. The proposed method not only generates precoding vectors that are orthogonal to the precoding vectors of the previously selected users and are highly correlated with the codebook vector of each user but also adopts the quantization error in approximating the SINR, which eventually provides a significantly more accurate SINR than the conventional SINR-based user selection techniques. Computer simulations show that the proposed method enhances the sum rate of the conventional SINR-based methods by at least 2.4 (2.62) bps/Hz when the number of transmit antennas and number of receive antennas per user terminal is 4 and 1(2), respectively, with 100 candidate users and an SNR of 30 dB.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.163-165
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• 2008

In this paper we compare performance of exponential effective SINR mapping (EESM) with traditional actual value interface (AVI) approach for various modulation and coding schemes (MCS) in terms of coded bit error rate (BER) or block error rate (BLER) using different transmission schemes. This paper provides explanation and comparison of the two algorithms for single input single output (SISO), and single input multi-output (SIMO, 1X2) in OFDM systems. We calibrate the value of beta ($\beta$) in EESM using large number of channel realizations, here $\beta$ is a calibration constant. This paper also presents importance of beta value in EESM and how it improves the performance of OFDM wireless systems. We propose different modulation and coding schemes. Here we consider Standford university interim (SUI) channel models. Furthermore this paper also shows the detail observation of the two algorithms. Finally the conclusion review given for short summary.