• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1982.10a
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• pp.47-50
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• 1982

A baseband data transimission system is implemented on a microcomputer for performance study on some NRS line codes. These codes are compared in terms of eye width, BER, and power spectrum.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.139-139
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.313-313
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• 2004

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.149-154
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• 2004

In this paper, Interference-Cancelled CDMA system using binary ZCD spreading codes is introduced. Proposed Interference-Cancelled CDMA system can be usefully used for the intra-cellular Interference-Cancelled wireless communication systems. Binary ZCD spreading code sets have various sequence period and family sizes and the ZCD properties of them are very effective for Interference-cancelled CDMA Systems. In this paper, we mathematically analyzed the system performance of our proposed Interference-Cancelled CDMA system in the AWGN channel and various interference environments such as MAI and MPI. Furthermore, using the BER performance simulation we certify the available interference cancellation properties of the proposed system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.19-25
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• 2005

This paper describes a synthesis method for a self-equalized dual-passband filter. Compared to conventional dual-passband filter, a self-equalized dual-passband filter can reduce BER(bit error rate) in digital data communications and does not need an external equalizer for group-delay equalization. To validate the synthesis technique, a 10-pole dual-mode dual-passband filter which has two self-equalized 5-pole elliptic response passband is synthesized.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.740-745
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• 2013

This paper presents BER, FER performance comparison, especially on PHY mode of IEEE 802.15.4g and IEEE 802.11 under AWGN channel through a simulation, which is communication method using identical frequency bandwidth in M2M environment. This considers suitable communication method of required parameter. It is advantageous that FSK method is used in situations where the system require low complexity and inexpensive structure. And OFDM method is considered for system performance. Further, when the high throughput and various traffic characteristics of the system are required, it can be considered that the method of IEEE 802.11 OFDM PHY mode is used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1064-1070
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• 2010

In this paper, unuse frequency resources additionally in radio communication system and proposed fan shape receiver and interference exclusion flag that can overcome interference by frequency selective special quality. Analyzed results in actualer situation with channel conclusion error. Because frequency selective special quality is strong, there was excellent performance elevation than Conventional space - frequency block code receiver when use together MMSE fan shape receiver and interference exclusion radical in situation that the interference amount is big. Iin case channel conclusion error is small, there were Performance gains of 7dB in (MSE = 0.001) $BER=2{\times}10^{-3}$.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.450-457
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• 2002

Conventional channel estimation methods for OFDM system have not the robust characteristics relating to various mobile speed. To solve this drawback in conventional methods, we propose the channel estimation method for OFDM, which has a good performance and computational complexity in consideration of other methods. Proposed method uses a block frame structure within a whole channel in contrast with conventional methods such as PSAM and ESAE. This concept prevents overall performance from diverging or showing a poor one. The analytical results demonstrate the proposed method outperforms PSAM and ESAE in terms of MSE and BER performance under all Rayleigh fading environment. Considering the simulation performance and computational complexity, proposed method shows better characteristics than conventional methods for OFDM and has not an error floor even in a severe Rayleigh fading environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1196-1202
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• 2007

In this paper, the effects of performance improvement far the OFDM based satellite communications are analyzed with applying the CI(Carrier Interferometry)-OFDM and channel coding scheme considering the group delay and gain ripple characteristic as well as the nonlinear characteristic of the transponder. Comparing the BER between traditional OFDM and CI-OFDM, the degree of performance improvement is presented in AWGN channel environments for specified backoff condition of HPA. The simulations are performed with the 36 MHz bandwidth of transponder channel, 120 Mbps transmission rate, and 16 QAM modulation scheme between ideal and worst case condition. It is shown that the improvement measure by the CI-OFDM and channel coding for the group delay and nonlinear characteristic outperforms that for the gain ripple in terms of performance degradation presented by the individual characteristics. And the simulation results show that the effects of improvement by the CI-OFDM outperforms the effect by the applied channel coding, particularly in worst case condition.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.179-183
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• 2002

본 논문에서는 광대역 CDMA망에서 음성, 비디오, 데이터와 같은 멀티미디어 서비스를 제공하기 위해서 다양한 서비스 특성에 적합한 액세스 제어 방법을 제안한다. 즉 서비스별로 다른 Eb/No 값을 이용함으로써 서비스의 BER을 조절하고 음성과 비디오의 전송률이 시간에 따라 변하는 특성을 이용하여 데이터의 전송률을 제어하는 방법을 제안하였다. 또한 각 방법에 대한 시뮬레이션과 분석을 수행하였다. 성능 분석결과 제안된 액세스 방법을 사용할 경우 데이터에 대한 지연을 통해 전체적인 outage 발생확률을 감소시킴을 알 수 있었다.