• The Journal of the Acoustical Society of Korea
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• v.8 no.4
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• pp.74-82
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• 1989

In this paper, we have studied on the methodologies of implementation and the performance evaluations about the real-time packetized coding of multi-channel speech signals. Our suggested coding algorithm is very, simple and it has majorly the data handling operations rather than the numerical calculations. And it gives about $40\%$ of compression ratio with less than the conventional codings. Nevertheless, using this algorithm, we can save the memories for the speech signal and we can raise the efficiency of the channel transmission. Especially because of its simplicity of algorithm, we can easily obtain the merits of the multi-channel operations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.760-770
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• 2002

Transmit diversity is an efficient diversity technique to improve performance and spectrum efficiency in wireless communication . Coding scheme designed for the transmit diversity is called space-time coding. In this paper, we propose a training structure to apply the transmit diversity to improve the performance of IEEE802.11a OFDM systems. Based on this training structure, we propose a channel estimation scheme using curve fitting. Also we compare and evaluate the performance of space-time codes. The performance of both diversity using space-time codes and channel estimation scheme is investigated by computer simulation in quasi-static 2-ray rayleigh fading environment.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.237-240
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• 2000

In this paper, we design the system that support data rate of 6Mbps(BPSK), 12Mbps(QPSK), 24Mbps(16-QAM) with OFDM, and the performance of this system analyze in the indoor channel when BER is 10$\^$-3/. In this simulation, first, we analyze performance of the system with and without channel coding. As the result, the coding gain of each system is 2㏈, 1.6㏈, 2㏈ when BER is 10$\^$-3/ Second, In the case of 16-QAM/OFDM, The effect of soft decision channel decoding method improve 2㏈ than hard decision when BER is 10$\^$-3/.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.956-970
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• 2015

In this paper, we study the design of network coding for the generalized transmit scheme in multiple input multiple output Y channel, where K users wish to exchange specified and shared information with each other within two slots. Signal space alignment at each user and the relay is carefully constructed to ensure that the signals from the same user pair are grouped together. The cross-pair interference can be canceled during both multiple accessing channel phase and broadcasting channel phase. The proposed signal processing scheme achieves the degrees of freedom of ${\eta}(K)=K^2$ with fewer user antennas.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.582-584
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• 2011

This paper presents a Channel DiVision (CDV) scheme for transform-domain distributed video coding. In the proposed system, we employ the symmetric motion estimation to generate high quality side information for Wyner-Ziv (WZ) frames. Also, the decoder estimates the distortion of the side information, which is used to classify the transmitting channels for WZ frames. Each channel has a different expected noise. Then, the encoder allocates an appropriate number noise. Then, the encoder allocates an appropriate number present rate-distortion performance results and comparisons with existing state-of-the-art algorithms and H.264.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.544-550
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• 2009

In this paper, we proposed the radio wave propagation characteristics of the next-generation ultrafast wireless communication system in millimeter-wave fading channel. For considering doppler shift and Rayleigh fading simultaneously, the fading simulator of Jakes model implemented and analyzed the performance of the next-generation wireless communication system. In addition, the error rate characteristics of DS-CDMA system analyzed in the millimeter-wave fading channel and the system performance improved by coding technique and diversity technique.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.335-339
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• 2011

Recently, we reported a single input channel joint transform correlator for the color pattern recognition which decomposes the input color image into three R, G, and B gray components and adds those components into a single gray image in the input plane. This technique has the merit of a single input channel instead of three input channels. However, we found this technique has some problems with discrimination impossibility in the case of a simple primary color pattern which results in the same gray level through the addition process. Thus, we propose a modified coding technique which selectively recombines the decomposed three R, G, and B gray components instead of the simple adding process. Simulated results show that the modified coding technique can accurately discriminate a variety of kinds of color images.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.97-100
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• 2003

The quasi-complementary turbo codes (QCTC) proposed by Kim [1] is used for a fast hybrid ARQ scheme with incremental redundancy and adaptive modulation coding in the cdma2000 1xEV-DV [2]. The QCTC provides various code rates with good performance, a very simple encoder structure, and an inherent channel interleaving. It is shown that the QCTC is a unified scheme of channel coding and channel interleaving. In this paper, we introduce the properties of QCTC and various hybrid ARQ-QCTC schemes for the system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.12
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• pp.3200-3219
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• 2013

This paper proposes an adaptive combined scalable video coding (CSVC) system for video transmission over MIMO-OFDM (Multiple-Input Multiple-Output-Orthogonal Frequency Division Multiplexing) broadband wireless communication systems. The scalable combination method of CSVC adaptively combines the medium grain scalable (MGS), the coarse grain scalable (CGS) and the scalable spatial modes with the limited feedback partially from channel state information (CSI) of MIMO-OFDM systems. The objective is to improve the average of peak signal-to-noise ratio (PSNR) and bit error rate (BER) of the received video stream by exploiting partial CSI of video sources and channel condition. Experimental results show that the delivered quality using the proposed adaptive CSVC over MIMO-OFDM system performs better than those proposed previously in the literature.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.139-144
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• 2004

In order to transmit various types of multimedia data (i.e. voice, video, and data) over a wireless channel, the coding and modulation scheme needs to be flexible and capable of providing a variable quality of service, data rates, and latency. In this paper, we study a mobile multimedia COMA network combined with the concatenated Reed-Solomon/Rate Compatible Punctured Convolution code (RS/RCPC). Also, this paper propose the combination of concatenated RS/RCPC coder and COMA RAKE receiver for multimedia COMA traffic which can be sent over wireless channels. From the results, using a frequency selective Rayleigh fading channel model, it is shown that concatenated RS/RCPC coder at the wireless physical layer can be effective in providing reliable wireless multimedia CDMA network. And the proposed scheme that combine concatenated RS/RCPC coder and CDMA RAKE receiver provides a significant gain in the BER performance over multi-user interference and multipath frequency selective fading channels.