• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.23-36
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• 2016

We propose a new type of OFDM-CDMA scheme which allows large inter-user timing offset using zero correlation zone(ZCZ) code in conjunction with block spreading technique. Moreover to maximize spectral efficiency, the proposed OFDMA does not have guard time(GT). This is opposite to the trends in the conventional schemes where GT are supposed to be larger to allow larger inter-user timing offset. It is remarkable that the proposed GT-free OFDM-CDMA scheme completely cancels inter-user interference in the multipath fading simply by despreading process. This inter-user interference-free feature still remains even there exist inter-user timing offsets as large as multiple OFDM symbols. Although the self-user interference exists due to no GT, it can be effectively suppressed by simple successive interference cancellation(SIC) from the first symbol in spread block as it is free from inter symbol interference(ISI).

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.8-12
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• 2015

A Holographic data storage has some advantage of fast transmission, short access time and high storage capacity. However, it has several problems such as inter-symbol interference, inter-page interference and misalignment. Especially, for multi-level holographic data storage system, since one pixel contains more than 1bit, the system is more vulnerable to the error. In this paper, we propose a 3/4 modulation code which mitigate inter-symbol interference for 4-level holographic data storage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.574-578
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• 2014

A holographic data storage (HDS) has some advantages of high storage capacity, fast transmission, and short access time. However, there are two major concerns with the system which are two-dimensional (2D) inter-symbol interference (ISI) and inter-page interference (IPI). Thus, this paper proposes a 4-level 6/9 modulation code which mitigate inter-symbol interference (ISI).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.100-113
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• 2018

The Proximity Service, which is one of the most popular network capacity improvement methods, uses the frequency reuse in order to increase the frequency efficiency. As a result, inter-cell interference between cellular and proximity service users occurs at a cell edge. In this paper, we proposed a mitigation scheme for inter-cell interference, where we suggested a new function of and eNB with ProSe function exchanging information about ProSe parameters and ProSe user equipment with neighboring cells via the X2 interface. As the first step, the resource which did not cause the inter-cell interference problem were pre-allocated through the frequency sensing in the ProSe direct discovery. As the next step, the inter-cell interference problem was solved by reallocating appropriate resources based on the ProSe application code, the ProSe application QoS, the ProSe application ID and validity timer in ProSe direct communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.501-508
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• 2006

Orthogonal frequency division multiplexing-code division multiplexing access(OFDM-CDMA) systems without guard interval can enhance the bandwidth performance more efficiently than the systems with guard interval. In this paper, a new technique for an OFDM-CDMA system without guard interval, which can eliminate inter-symbol interference(ISI) and inter-channel interference(ICI), is presented. The proposed algorithm is a new demodulation technique, based on the Pseudo-Decorrelator, and it is named PD algorithm. Simulation results show that the PD algorithm can combat ISI and ICI efficiently for an OFDM-CDMA system without guard interval. The BER performance of the PD algorithm is much better than that of a conventional OFDM-CDMA system without guard interval.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5C
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• pp.329-337
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• 2005

In this paper, we propose a new type of RAKE receiver for complementary code keying (CCK) codes, which is suitable for the multipath channel with large delay spread. Our proposed system is based on channel matched filter (CMF) with decision feedback equalizer (DFE) and contains codeword DFE structure. In our system, inter chip interference (ICI) and inter symbol interference (ISI) generated due to multipath environments are calculated by using detected CCK codeword. Also it uses the error correcting capability of CCK codes, and it can remove ISI and ICI at the same time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.739-743
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• 2013

In this paper, a two-dimensional (2-D) channel code for magnetic patterned media is proposed. Patterned media records an information bit on a magnetized dot. Since the space between adjacent tracks is narrow in order to increase the storage density, inter-track interference (ITI) and inter-symbol interference (ISI) can be problems. The amplitude of a bit signal can be corrupted by the 2-D ISI. The signal of the bit surrounded by the same value can be especially destructive, i.e. when its value is the same as the values of the eight surrounding bits. The proposed modulation coding scheme improves the decoding performance of patterned media by preventing this worst case and provides a better code rate than conventional channel codes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12A
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• pp.933-940
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• 2009

This paper proposes a robust detection scheme for quasi-orthogonal space-time block code over time-selective fading channels. The proposed detector performs interference cancellation and decision feedback equalization to remove the inter-antenna interference and inter-symbol interference when the channel varies from symbol to symbol. Cholesky factorization is used on the channel Gram matrix after performing interference cancellation to obtain feed forward equalizer and feedback equalizer. It is shown by simulations that the proposed detection scheme outperforms the conventional detection schemes and the exiting detection schemes to time-selectivity.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.100-106
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• 2006

In this paper, we proposed a TxID(Transmitter Identification) system using ZCD (Zero Correlation Duration) code as interference-cancelled spread codes for single frequency network of ATSC terrestrial DTV broadcasting. ZCD codes are simply implemented and have ZCD characteristics. Then, Proposal system can fundamentally solve interference problems caused by ICI(Inter Code Interference) and MPI(Multi-Path Interference) which happens in TxID system using spread coding method. Also, those can cancel truncated error which happens at watermarking for TxID since those can remove its period. In this paper, we identified the availability of TxID system applying interference-cancelled ZCD codes by analyzing DER (Detection Error Rate) which is simulated in various interference environments such as AWGN, ICI, and MPI.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.125-130
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• 2011

In this paper, there was compared to the performance of the Auto Correlation Feature of each code using Spreading code for improving the data transmission technology in T-DMB disaster broadcasting. Generally, wireless mobile communication environment such as DMB occur the Inter Code Interference and the Multi-Path Interference in the process of the identification of the transmitter from the receiver. To solve this problem, spreading code technology was able to improve the security property. Also, it will be able to use in many fields of signal processing, because to control a period of the code can be variable. Therefore, in this paper, we studied to compare the performance of excellent orthogonal Golay code, Kasami code and ZCD(Zero Correlation Duration) code.