• 한국통신학회:학술대회논문집
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• 한국통신학회 1987년도 춘계학술발표회 논문집
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• pp.191-195
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• 1987

When a 160QAM receiver in the band of spread spectrum system is interfered with a pseudo-random frequency-hopp-ing signal the interference signal has the form of the pulse amplitude probability density function. Each interfrering pulse amplitude probability density function Each interfering pulse amplitude is dependent upon theprobability density function of hopping frequency and the selectivity characteristic of 16QAM system in this paper the error rate equation of a system performance has been derived in the above condition which are interfrerence form and impulsive noise environmensts. The results of system analysis show us that the system performance is de-graded by impulsive noise and interference power, which improved as the frequency hopping bandsidth increases whit respect to receiver bandwidth

• ETRI Journal
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• 제25권5호
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• pp.418-421
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• 2003

We propose an unbiased signal-to-interference ratio (SIR) estimator for the high speed downlink packet access (HSDPA) system. The proposed SIR estimator solves the problem of underestimation present in conventional SIR estimators and is suitable for channel quality measurement in the adaptive modulation and coding scheme of HSDPA, which requires accurate SIR estimation for optimum adaptive modulation and coding selection. Our analysis and simulation results demonstrate the improved estimation performance of the proposed SIR estimator.

• 대한임베디드공학회논문지
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• 제5권3호
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• pp.136-143
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• 2010

Embedded systems widely used for wireless communication such as W-LAN, Bluetooth and ZigBee operate on ISM (Industrial, Scientific and Medical) band but they can be seriously affected by electromagnetic interference radiated from ISM apparatus. Therefore C.I.S.P.R. reports proposed limits for the protection of telecommunication from interference from ISM equipment. In this paper, we clarify the methods for calculating limits for disturbance signal for Embedded Systems in ISM band and propose simple way of calculating limits for interference signal in both above and below 1 GHz band cases.

• 전자공학회논문지S
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• 제34S권11호
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• pp.148-155
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• 1997

Ths signal processing technqiue of FET type electrolyte sensors using the back propagation neural network was studied to reduce the interference effects of the different electrolytes. The FET-type electrolyte sensors, pH-ISFET, K-ISFET, and Ca-ISFET, were prepared to measure the pH, K, and Ca electrolytes. Neural network consisted of three layers was learned with 8 patterns and 9 patterns. The sensor output obtained with arbitrary concentrations was processed by the learned neural network. The errors obtained from calibration curve for pH, K, and Ca were .+-.0.039 pH, .+-.2.508 mmol/l, and .+-.1.807 mmol/l, respectively, without considering the interference effects. The errors of the network output for pH, K, and Ca were reduced to .+-.0.005 pH, .+-.0.436 mmol/l, and .+-.0.381 mmol/l in case of 9 patterns, respectively. the signal processing using the neural network can reduce the errors ofthe electrolyte sensor outputs caused by the interference effect, thereby providing effectiveness in the improvement of the sensor selectivity.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1984년도 춘계학술발표회논문집
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• pp.37-41
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• 1984

The error rate performance of amplitude phase keying system has been studied in the environment of cochannel interference and impulsive noise. We have derived the error probability equations of amplitude shift keying signal and phase shift keying signal, and combining the results, we have evaluated the circular APK signal which is the one of the several cases of APK arrays. Using the derived equations, the circular APK system has been evaluated in terms of carrier-to-noise power ratio(CNR), carrier-to-interferer power ratio(CIR), and impulsive index. The graphic results show us the best case and worst case of APK system, and good performance compared to the other systems in cochannel interference and impulsive noise.

• ETRI Journal
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• 제36권4호
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• pp.537-544
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• 2014

In this paper, we present a new inter-carrier interference (ICI) self-cancellation scheme - namely, ISC scheme - for orthogonal frequency-division multiplexing systems to reduce the ICI generated from phase noise (PHN) and residual frequency offset (RFO). The proposed scheme comprises a new ICI cancellation mapping (ICM) scheme at the transmitter and an appropriate method of combining the received signals at the receiver. In the proposed scheme, the transmitted signal is transformed into a real signal through the new ICM using the real property of the transmitted signal; the fast-varying PHN and RFO are estimated and compensated. Therefore, the ICI caused by fast-varying PHN and RFO is significantly suppressed. We also derive the carrier-to-interference power ratio (CIR) of the proposed scheme by using the symmetric conjugate property of the ICI weighting function and then compare it with those of conventional schemes. Through simulation results, we show that the proposed ISC scheme has a higher CIR and better bit error rate performance than the conventional schemes.

• 한국통신학회논문지
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• 제25권10A호
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• pp.1521-1528
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• 2000

In this paper we analyze the performance of a DS/CDMA system in LEO mobile satellite channels. The channel uses the Extended Suzuki model which is the product of a Rician distribution having a LOS component and a lognormal distribution due to shadowing. We assume that the signal transmitted from the satellite to the mobile undergoes the same fading for the whole coverage of signal's beam. The average bit error probabilities of double coverage system is calculated in this paper. The interference resulting from the reference satellite is calculated for mobile located in the middle of the double coverage region whereas the additive interference from next-satellite is included for mobile located in the edge of the double coverage region. The performance of the mobile's receiving signal is dependent on shadowing and the interference of the next-satellite. We can obtain an obtain an improved average bit error probability by using dual diversity over the conventional correlated receiver for similar shadowing conditions in the coverage area of the satellite channel.

• 항공우주시스템공학회지
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• 제15권6호
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• pp.50-58
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• 2021

Byteflight is developed based on RS-485 communication (an international standard), and it can be used as a data bus during the operation of an integrated avionics system in the latest aircraft. Therefore, the integrated avionics system can perform an effective and safe flight mission only when the accurate and seamless display of flight information, communication, and accurate functions of navigation are implemented. In this study, cause analysis and failure investigation were performed on screen abnormalities and communication interruptions due to signal interference in the Byteflight data bus of the integrated avionics system during aircraft operation. To improve signal interference between avionics units, the branch point and wiring path of the Byteflight data bus were changed, and the verification result of the improved method was also described.

• 한국전자파학회논문지
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• 제23권7호
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• pp.805-814
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• 2012

무선기기의 간헐적인 신호 또는 높고 낮은 진폭의 주기적인 신호 전송은 오디오 주파수에 간섭 신호를 발생시켜 근접 거리에 설치된 음향 기기에 잡음을 발생시킨다. 최근 이와 관련하여 Global system for Mobile Communication(GSM) 폰과 유사하게 간헐적인 신호 전송을 하는 Long Term Evolution(LTE) 폰에 의한 오디오 잡음현상이 보고되었다. 현재 국내 KN20 규격에서는 잡음에 대한 내성 능력을 확보하기 위하여 음향 및 TV 방송수신기의 내성 시험 기준 신호로 변조 주파수 1 kHz Amplitude Modulation(AM) 80 %와 Code Division Multiple Access(CDMA) 신호를 이용하고 있다. 본 논문에서는 LTE 폰의 출시에 따라 기존의 내성 기준 신호 AM과 CDMA를 GSM과 LTE 폰이 발생시키는 오디오 잡음의 수준과 비교한 후, 국내 음향 기기에 대한 내성 기준 신호의 개선을 제안한다. CDMA 신호는 음향 기기에 간섭을 거의 일으키지 않는 것으로 여겨지므로 시험 항목에서 삭제해도 무방할 것으로 판단된다. 반면, LTE는 많은 사용자가 이용하고 있으며, 음향 기기 등에 무시할 수 없는 간섭을 발생시킬 것으로 분석되므로 CDMA 신호를 대신하여 음향 기기 및 TV 방송 수신기의 내성 시험을 위한 시험 기준 신호로 규정하는 것이 바람직할 것으로 사료된다.

• 한국위성정보통신학회논문지
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• 제10권4호
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• pp.101-106
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• 2015

본 논문에서는 위성통신망의 주파수 효율 향상을 위해 중심국과 단말국이 동일 주파수 대역을 사용하여 위성으로 전송하는 동일 주파수 위성 전송 시스템을 고려한다. 이와 같은 시스템이 동작하기 위해 중심국은 자신이 송신한 신호가 위성을 거쳐 다시 되돌아 오는 자기 간섭 신호를 제거하여, 수신하고자 하는 단말국 신호만을 추출하는 자기 간섭 제거기가 필요하다. 중심국에서 제거하고자 하는 간섭 신호는 자신이 송신한 신호가 지연된 신호이기 때문에 일반적인 간섭 신호와는 달리 송신 신호를 지연시켜 제거가 가능한 신호이다. 이때 중심국 또는 위성에 있는 전력 증폭기의 비선형성을 고려하여 간섭 제거기를 설계해야 한다. 간섭 제거기는 송신 신호의 지연을 추정하고, 전력 증폭기의 비선형성을 반영하여 제거하는 부분과 잔여 오차를 적응 필터로 억제하는 부분으로 구성된다. 더불어, 모의 실험을 통하여 제안 방식의 효용성을 검증하고자 한다.