• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6A
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• pp.594-599
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• 2010

This paper studies the effect of the deployment position of the relay stations on the downlink signal-to-interference-noise-ratio (SINR) in multihop cellular networks. Two different relay deployment scenarios are considered where relay stations are located either inside cells or on the boundary among adjacent cells. The fundamental contribution is to compare fairly the average SINR between two scenarios with the proposed relay modeling framework that includes multi-cell geometries and inter-cell interferences. The mathematical results show that the SINR increases when relay stations are located inside cells because of higher received signal power.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.195-202
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• 2014

The Global Positioning System (GPS), which has various military and commercial applications, is designed to estimate the location of the specific user or object. In order to accurately estimate the location, GPS requires at least four satellite signals. The GPS receiver operates on extremely low signal-to-noise ratio (SNR) environment and it may suffer from various interference signals with the extremely high power. In this paper, we introduce a blind adaptive receiver based on the modified despreader, which suppress interference signals and detect GPS signals of interest without requiring explicit angle-of-arrival (AOA) information. We, also, provide the mathematical analysis for the signal-to-interference and noise ratio (SINR) of the modified despeader beamformer output. A representative computer simulation example is presented to illustrate the interference suppression performance of the considered GPS receiver and mathematical analysis of the SINR.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.400-404
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• 1998

본 논문에서는 도심지 이동 통신에서 SINR 성능을 향상시키기 위해 기존의 배열 안테나에 최소 평균 자승(LMS) 알고리즘을 적용하여 실제 배열 출력과 이상적 출력간의 최소 평균 오차(MSE)를 최소화하고 안테나의 배열로부터 가중치를 결합한 신호에 의해 방향성을 적절히 제어하여 간섭신호를 효과적으로 제거한다. 배열 출력 신호 대 간섭에 추가된 잡음비(SINR) 성능 분석에 적합한 삼차원적 분석을 사용하여 적응 배열 원소를 사용한 성능과 모노폴 안테나 원소에서 배열의 성능을 비교한다. 또한, SINR 패턴 각 비(PAR)를 사용하여 적응 배열 원소 방위, 내부 원소간의 간격들 그리고 입사 신호 방향들과 같은 다른 배열 매개 변수들에서 배열 성능을 계산하고 SINR 패턴의 양적 평가를 한다. 결과로서, 적응 배열 원소가 가정된 신호 환경에 있어 4상파형(quarterwave) 모노폴(monopole) 안테나 배열보다 더 바람직하다.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.248-256
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• 2015

In this paper, we model the interference plus noise signal for terrestrial cloud transmission systems and present bit error rate (BER) performances. Since terrestrial cloud transmission systems experience co-channel interference from one or more transmitters, they have to operate under a negative signal-to-interference plus noise ratio (SINR) region. The interference plus noise signal can be modeled as Gaussian random variable under the required SINR region and we observe the BER performance of the cloud transmission system using the derived model. Also, we propose an improved channel estimation scheme by averaging the channel estimates based on least square based interpolation scheme. Simulation results show that the cloud transmission system can operate under negative SINR region using the proposed channel estimation scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.71-77
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• 1998

In this Paper, the training principles and the control method of adaptive array antennas using the LMS and CMA algorithms for the $\pi$/4 QPSK signal is showed and the convergence characteristics, the adaptivity of directional pattern SINR and the replication of desired signal of adaptive arrays are compared and discussed each other. Computer simulation results showed that the SINR of LMS adaptive array was 13.8［dB］, and that of CMA was 12.8［dB］, and also the convergence characteristics of LMS was fast a little than that of CMA. The LMS adaptive array was also performed null point well for the interference signal direction than that of the CMA adaptive array.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.552-559
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• 2013

In this paper, the multiple-input multiple-output (MIMO) system with a precoder is considered in the transmit-correlated Rayleigh channels. We specifically target the MIMO system employing the minimum mean square error receivers. Based on random matrix theory, we first present a direct and generalized formulation for deriving a probability density function (PDF) of the signal-to-interference-plus-noise ratio (SINR). Then, we derive the accurate closed-form SINR PDFs for a small number of transmit and receive antennas. Based on the SINR PDFs, tight closed-form approximations of the symbol error rate (SER) are derived. Our analysis suggests that the SER approximations can be used to accurately estimate the error probabilities or as a useful tool for the system design.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.10-16
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• 2007

This paper analyzes the output signal-to-interference-plus-noise ratio (SINR) for a multiple-input-multiple-output (MIMO) multicarrier code division multiple access (MC-CDMA) system with minium mean square error receivers. A previous work of a single antenna MC-CDMA system cannot directly applied to a MIMO MC-CDMA system because some assumptions for single antenna do not match the case of multiple antenna. Therefore this paper expands the concept of freeness to MIMO system by using the Marcenko Pastur law. The analysis shows that the output SINR asymptotically converges to a deterministic value and finds the value on the assumption of freeness. From the analysis, it is easy to calculate bit error rate and the calculation is verified by simulations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.169-174
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• 2002

It has known that the DCMP(Directionally Constrained Minimization of power)and the ZF(Zero Forcing) can improve the SINR performance of an array antenna system by using spatial signature of wireless channel. This paper analyzes performance of DCMP and ZF in multiple scattering environments. To obtain the spatial signature of wireless channel. bothe DOA(Directional of Arrival) and AS(Angular Spread) of the received signals were estimated by using ESPRIT. The performance of the DCMP and the ZF was analyzed theoretically. Through computer simulation, the SINR performance were evaluated.

• Journal of Communications and Networks
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• v.11 no.1
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• pp.42-46
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• 2009

Superimposed training (SIT) design for estimating of time-varying multipath channels is investigated for mobile orthogonal frequency division multiplexing (OFDM) systems. The design of optimum SIT consists of two parts: The optimal SIT sequence is derived by minimizing the channel estimates' mean square error (MSE); the optimal power allocation between training and information data is developed by maximizing the averaged signal to interference plus noise ratio (SINR) under the condition of equal powered paths. The theoretical analysis is verified by simulations. For the metric of the averaged SINR against signal to noise ratio (SNR), the theoretical result matches the simulation result perfectly. In contrast to an interpolated frequency-multiplexing training (FMT) scheme or an SIT scheme with random pilot sequence, the SIT scheme with proposed optimal sequence achieves higher SINR. The analytical solution of the optimal power allocation is demonstrated by the simulation as well.

• Journal of Communications and Networks
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• v.10 no.2
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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.