• Journal of Navigation and Port Research
• /
• v.38 no.4
• /
• pp.349-356
• /
• 2014

In the underwater communication, the performance of system is reduced because of the inter-symbol interference occur by the multi-path. In the recent years, to deal with poor channel environment and improve the throughput, the efficient concatenated structure of equalization, channel codes and Space Time Codes has been studied as MIMO system in the underwater communication. Space Time Codes include Space Time Block Codes and Space Time Trellis Codes in underwater communication. Space Time Trellis Codes are optimum for equalization and channel codes among the Space Time Codes to apply in the MIMO environment. Therefore, in this paper, turbo pi codes are used for the outer code to efficiently transmit in the multi-path channel environment. The inner codes consist of Space Time Trellis Codes with transmission diversity and coding gain in the MIMO system. And Zero Forcing method is used to remove inter-symbol interference. Finally, the performance of this model is simulated in the underwater channel.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.29-32
• /
• 2000

시변 페이딩 채널환경에서 DS-CDMA 다중 사용자 환경의 이동통신 시스템에서 채널의 효율을 높이기 위해 학습 신호열을 사용하지 않는 새로운 블라인드 등화 기법을 제안한다. 블라인드 등화 기법 중에서 가장 성능이 좋은 CMA(Constant Modulus Algorithm)는 가변하는 페이딩 채널환경에서 채널등화에 효과적이지 못하다. 따라서 Kalman 필터와 CMA를 결합한 새로운 등화 기법은 자승 오차와 Eye-Pattern의 성능 비교를 통해 기존의 방법 보다 우수함을 확인할 수 있었다.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2006.07a
• /
• pp.622-622
• /
• 2006

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1189-1191
• /
• 2005

This paper introduces the least-squares order-recursive lattice (LSORL) Laguerre smoother that has order-recursive smoothing structure based on the Laguerre signal representation. The LSORL Laguerre smoother gives excellent performance for a channel equalization problem with smaller order of tap-weights than its counterpart algorithm based on the transversal filter structure. Simulation results show that the LSORL Laguerre smoother gives better performance than the LSORL transversal smoother.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.3
• /
• pp.248-258
• /
• 1991

In this paper, ISI cancellation capabilites in the frequency selective fading channels of the equalizer emplouing individual tap LMS(ITLMS) algorithm and of th equalizer using the lattice structure have been investigated through the computer simulations in terms of bit error rate and convergence speed.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.281-282
• /
• 2008

Turbo equalizers which use MAP (maximum a posteriori probability) equalizer or MMSE (minimum mean square error) equalizer have shown high performance and adoptability [1], [2]. In this paper, we show that the BP (belief propagation) algorithm can also be applied in equalizer and when it is connected with channel code, it can replace the MAP equalizer with similar complexity and performance.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.8B
• /
• pp.1100-1108
• /
• 2001

PC-BLRNN을 이용한 무선 비동기 전송 채널 등화기가 본 논문에서 제안되었다. BLRNN은 쌍선형 다항식에 기초한 것으로 MLPNN 형태의 신경망보다 비선형 시스템의 모델링에 탁월한 성능을 보여왔으므로, 매우 비선형적이고 시계열적 특성을 가지는 무선 비동기 전송 채널 등화기에 이용될 수 있다. PC-BLRNN 등화기가 QPSK 신호에 대해 C-DFE, C-MLPNN 등화기 등과 실험적으로 비교되었는데 그 결과, 기존의 등화기들 보다 제안된 PC-BLRNN 등화기가 MSE와 BER의 성능에서 모두 매우 향상된 결과를 보여주었다.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1920-1923
• /
• 2002

This paper proposes an impulse response shortening algorithm applicable to decision feedback equalization of single carrier wideband signal. When he impulse response shortening methods for narrowband signaling are applied to single carrier wideband signals, they result in noise enhancement problem, significantly deterioriting the receiver performance. This problem can be alleviated by educing the eigenvalue spread ratio of the impulse response, which can be achieved by adding additive white noise with small variance to the impulse response of the channel. The performance of the proposed scheme is verified by computer simulation.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.08a
• /
• pp.1-4
• /
• 2000

In this paper, A useful nonlinear function for the RBF(Radial Basis Function) equalization is proposed. This proposed function need not calculate an exponential function that is generally used for conventional RBF equalizer and uses the only four rules of arithmetic. Therefore the computational requirement for the RBF equalizer with the proposed function is decreased. As a computer simulation result, the equalizer with the proposed function effectively reduce nonlinear intersymbol interference, caused by nonlinear communication channel.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.08a
• /
• pp.25-28
• /
• 2000

본 논문에서 제안한 OFDM 시스템은 대역 사용 효율을 높이기 위하여 순환 접두부를 두지 않고 심볼을 전송한다. 그로 인해 존재하는 채널간의 간섭과 심볼간의 간섭을 제거하기 위해 DFE를 사용한 등화 기법을 제안하고, 다중 경로가 존재하는 무선 채널 환경에서의 기존의 순환 접두부를 사용하는 OFDM 시스템과 제안한 시스템을 모의 실험을 통해 각 시스템의 성능을 비교 분석한다.