• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.154-161
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• 2013

This paper presents the signal-to-interference plus noise ratio (SINR) estimation of IEEE 802.16m WirelessMAN-Advanced mobile station with simulation and implementation results. The downlink signal of IEEE 802.16m has two kinds of A-Preambles: the PA-preamble and the SA-preamble. This paper proposes the efficient method of estimating SINR with A-Preambles, by measuring noise power from PA-preamble and measuring interference power and signal power from SA-preamble. The proposed SINR measurement block contains important features such as subcarrier phase rotation elimination and simplified dB transform. The result of this paper is integrated to ETRI's IEEE 802.16m test mobile station, used for decision of adaptive-modulation-and-coding (AMC) and hand-over. It showed good measurement performance in simulation and unified system link test also.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.8
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• pp.890-894
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• 2014

In this paper, we derive the CRLB (Cramer-Rao Lower Bound) of effective carrier-to-noise power ratio ($C/N_0$) estimation for a GPS (Global Positioning System) L1 C/A (Coarse/Acquisition) signal under band-limited white noise jamming environments. The quality of a received GPS signal is commonly described in terms of its $C/N_0$, implying that the noise is white and thus can be described by scalar noise density. However, if some intentional interference is received to a victim GPS receiver, then the $C/N_0$ is no longer the efficacious performance indicator. The correct and straightforward measurement to analyze the receiving situation is the effective $C/N_0$. In this paper, we consider a band-limited white noise jamming whose bandwidth is 2MHz and is the same as one of the first null-to-null bandwidth of the GPS L1 C/A signal.

• ETRI Journal
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• v.45 no.5
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• pp.899-909
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• 2023

In mobile communication, the most exploratory technology of fifth generation is massive multiple input multiple output (MIMO). The minimum mean square error and zero forcing based linear detectors are used in multiuser detection for MIMO single-carrier frequency division multiple access (SCFDMA). When the received signal is detected and regularization sequence is joined in the equalization of spectral null amplification, these schemes experience an error performance and the signal detection assesses an inversion of a matrix computation that grows into complexity. Ordered successive interference cancelation (OSIC) detection is considered for MIMO SC-FDMA, which uses a posteriori information to eradicate these problems in a realistic environment. To cancel the interference, sorting is preferred based on signal-to-noise ratio and log-likelihood ratio. The distinctiveness of the methodology is to predict the symbol with the lowest error probability. The proposed work is compared with the existing methods, and simulation results prove that the defined algorithm outperforms conventional detection methods and accomplishes better performance with lower complication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1320-1331
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• 1992

The error rate equation of FH/MFSK signal of repeated diversity received over m-distribution fading channel with partial-band interference has been derived and the error rate has been evaluated to show in figures as a function of signal to noise ratio, signal to interference ratio, fading figure, repeated number, partial-band interference fraction and power correlation coefficient between signal and interference. In this paper, we assumed that repeated diversity technique is used in transmitter against fading occurred in mobile radio channel. By comparing the error rate performance in diversity against fading and the obtainable degree of improvement of error performance with diversity technique has been found out. From the result, it is known that error rate performance deteriorates more as $\rho$ becomes small i.e., the partial-band interference gives more effect on error performance than full-band interference. Also when the values of $E_b/N_1$ and $\rho$ are small. as depth of fading diversity technique.

• Journal of Communications and Networks
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• v.16 no.1
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.166-173
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• 2004

Satellite communication system uses a high non-linear HPA(high power amplifiers) in the earth station and satellite transponder. Therefore, it is important to consider the nonlinear effect of HPA on the communication system. In this paper, we find the variation of power spectrum density by nonlinearity HPA and the change of harmonic component according to IBO (input back-off). When the BPSK is used for satellite communication system, we analyze BER performance including the external co-channel interference (CCI) and the adjacent channel interference (ACI) resulting from the HPA nonlinearity. BER degrades as ACI magnitude grows up when the uplink SNR, uplink SIR (signal to co-channel interference power ratio) and downlink SIR are constant at some level. In case there is only non-linear HPA in the satellite, it is shown that BER considerably depends on the ACI magnitude ACI. When there are two non-linear HPAs in the both earth station and satellite, much BER degradation results from the CCI and ACI.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.4
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• pp.285-301
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• 1988

The symbol error rate equations of multi-level quadrature PRS(QPRS) system have been derived in the individual and composite environment of Gaussian/impulsive noise, cochannel CW interference, carrier offset, phase jitter and fading. And using the derived error rate equations, the probability of error has been evaluated and shown in graphs as functions of carrier to noise power ratio, carrier to interference power ratio, phase error, impulsive index, the ration of Gaussian noise to impulsive noise power component, signal to noise power ration in phase locked loop(PLL), and fading figures. The rseults show that the error rate performances are generally more more degraded by impulsive noise than by Gaussian noise. But on the contrary the erors occurred more frequently by Gaussian noise than impulsive noise in a fading environment.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.55-67
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• 1995

The error rate equations of MPSK and DS/MPSK radio signals transmitted through the m-distributed fading channel in Gaussian noise and tone interference environments have been derived. Using the derived equations, the error rate performance is evaluated and shown as functions of carrier-to-noise ratio, carrier-to-interference ratio, processing gain, fading index and the number of diversity branches. The derivation has been done for two cases. The first case assumes that only the signal is undergoing the influence of fading, and the second case assumes that both signal and interference are undergoing the influence of fading simultaneously. From the obtained results, we have known that the error performance of MPSK signal is improved by using diversity technique and direct sequence spread spectrum technique even in a fading environment. Also comparing the error rate performance of two cases, the latter is worse than the former.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.39-44
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• 2013

Long Term Evolution (LTE) - Advanced has developed Heterogeneous Network (HetNet) that consists of a mix of macrocells and low-power nodes such as picocells to improve the system performance. Also, to encourage data offloading in HetNet, Cell Range Expansion (CRE) have been introduced. In this paper, we propose a cell selection scheme based on Signal to Interference plus Noise Ratio (SINR) for optimal offloading effect. And we manage the interference for user located in cell range expanded region using Almost Blank Subframe (ABS) with flexible ABS ratio to improve the spectrum efficiency in time domain. Simulation results show that proposed scheme can improve spectrum efficiency of macrocell and picocell user. Eventually, proposed scheme can imporve overall user performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.868-878
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• 1990

Upon introducing satellite communication system to Korea, one of the important problems to cope with is the effect from the probable intentional interference I.e. jamming. In this paper we have investigated how much the performance of ordinary PSK signal and Directed Sequence Spread Spectrum PSK signal degrade by the effect of jamming in the satellite communication system. In analysis we have consider the M ary PSK signal and the liniter type nonlinear satellite transponder in an environment of uplink tone or noise jamming plus Gaussian noise and downlink Gaussian noise. Using the derived error rate equation we have evaluated the error performance of BPSK and QPSK systems and compared this with that of DS BPSK system. Form the results, we know that the nonlinear satellite system is degraded more severely by the effect of noise jamming than tone jamming and the effect of tone jamming on the error rate performance can be reduced more remarkably by increasing the process gain in DS BPSK system rather than increasing carrier to jamming noise power ratio in conventional BPSK system.