• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1571-1578
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• 2014

Binary CDMA is a new standard technology for wireless communication developed by our country that makes high speed communications and good quality of services for multimedia data such as voice and video. In this paper we researched the design and implementation of a wireless Video Transmitter and Video Server - the main devices for the Automobile Wireless Camera System - based on the Binary-CDMA technology that makes them freely installed in any place without wired cables restriction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1167-1176
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• 2004

This paper presents an adaptive MC-CDMA transmission for downlink in mobile satellite system and simulation results on Ka-band mobile satellite channel. The simulation results show that the proposed scheme support a throughput of several tens of Mbit/s and a spectral efficiency range of 1 bit/s/Hz to 4.7 bit/s/Hz according to channel environments due to the adaptive broadband satellite transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1486-1491
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• 2000

A Multicarrier system required a lower speed paralled-type of signal processing in contrast to a fast serial processing in a single carrier CDMA system. For the analysis we evaluate MC-CDMA system performance with that of a single-carrier CDMA system and a multi-carrier CDMA system based on the various jamming conditions. Also we studied to the capacity level against the threat environment through the performance comparison in commercial CDMA system and Limiting repeater system. as a result we found that M-CDMA system has a robustness to narrowband interference and multipath environments like as a Rayleigh fading.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.322-330
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• 2011

Binary CDMA is a new standard technology for wireless communication developed by our country that makes high speed communications and good quality of services. In this paper we researched the development methods and design of a wireless CCTV System based on the Binary-CDMA technology that makes it freely installed in any place without cables and laying works.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1107-1114
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• 1999

In this paper, we analyze the effect of co-channel interferers coming from other systems with composite log-normal shadowing and Nakagami fading on the capacity of the imperfect power-controlled DS/CDMA cellular system. The analytical results are compared with the results of Prasad and Jansen in which they derive the result under the condition of imperfect power-control of DS/CDMA system and without considering interference. And the outage probability is calculated fro the effect of the log-normal/Nakagami faded inferers on DS/CDMA system using Schwartz and Yeh's method. With the deviation of outage probability, we analyzed the decreases in the capacity of DS/CDMA system with the variation of the paramenters of the imperfect power-control, the fadig index, the processing gain, the power ratio, the voice activity factor, and the number of interferers. Analysis reuslts have shown that the capacity of DS/CDMA system is very sensitive to the imperfect power-control and the number of interferers. It is shown that the DS/CDMA system capacity decreased according to increase of the deviation of the impertect power-control, the increase of the fading, and the increase of interferer number.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1135-1142
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• 2006

This article presents a new asynchronous MC-CDMA system to implement multiple data rate communications. In a W-CDMA downlink, the OVSF code is used for spreading code for various multimedia traffic. Proposed system utilizes the OVSF code that generated by generation property for spreading. The proposed MC-CDMA system use different lengths of OVSF code as a spreading code according to their data rate. The groupwise processing is accomplished by code grouping in OVSF code generation tree. Between each group, the code grouping interference canceller is performed to cancel other group interference. At that time the proposed receiver does not require any information about interference users. For the analysis of average BER performance, we propose system model and computer simulation were used. We also compare the system performance with that of a single rate MC-CDMA system used orthogonal code as a spreading code.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1011-1016
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• 2003

In this paper, we investigate the relationship between the intermodulation signal of 2-tone and CDMA spurious emission of HPA. And confirm that the fifth IMD signal of HPA has more important effect upon CDMA ACPR characteristics than the third IMD signal. We present the method for the power amplifier to satisfy the 2-tone and CDMA specification simultaneously, and that is to use the predistorter for improving the third IMD signal of 2-tone for the power amplifier which is tuned to satisfy the CDMA specification and not to satisfy the 2-tone specification. The result by using the method which is presented from this paper shows that the ACPR is improved about 2 dB for CDMA 1FA(frequency allocation) signal and the third IMD signal is improved about 20 dB for CW 2-tone signals and we confirmed the specification is satisfied simultaneously.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.110-118
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• 2009

The PB/MC-CDMA(Partial Block Multi Carrier Code Division Multilple Access) system can improve the performance by reducing the ICI(Inter-Code Interference) between users. Also, this system can achieve the frequency diversity gain by avoiding ISI(Inter Symbol Interference). Therefore, the performance of PB/MC-CDMA system is better than that of conventional MC-CDMA(Multi Carrier Code Division Multiple Access) system. However, similarly to other multi-carrier systems, it still has a PAPR(Peak to Average Power Ratio) issue. In this paper, we propose a peak power reduction technique involving optimized spreading code selection without side information for the PB/MC-CDMA. The PB/MC-CDMA system in each block of units reuses the code so the extra code will be remained. This extra code is divided into several groups to calculate the PAPR and solving the PAPR problem by transferring the selected code which has minimum peak power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.745-751
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• 2002

The performance of existing CDMA-type multiple access data transmission systems is limited by interferences due to adverse mobile communication channel characteristics. Among them, the multi-user interference becomes one of the major performance degradation factors because the signal-to-signal orthogonality can be easily perturbed when numerous user signals are distorted by multipath fading channels and mixed together. In order to enhance the performance of CDMA-type systems by suppressing the multi-user interference, we have adopted chip-based cyclic prefix insertion along with adaptive one-tap DFE equalization into MC-DS-CDMA, which is known for its robustness in the frequency selective multipath fading channel environment. In order to assess the performance of the proposed system, a set of computer simulations is performed in the reverse link in which each user signal undergoes different multipath Rayleigh fading. The results show us a superior performance of our system over other CDMA systems in terms of SNR to BER measurements.

• Journal of Digital Contents Society
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• v.6 no.3
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• pp.137-142
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• 2005

CDMA scheme has received a great deal of attenttion as a multiple-access method for future mobile networks. Its main advantage: are higher radio capacity and the capacity of flexible data tranmission. And CDMA scheme is a key technology in the proposals submitted to the ITU on next generation multimedia system with integrated services, namely real-time voice services and non real-time data services. In this paper, capacity evaluation of multiple-input multiple-output(MIMO) Multi-Carrier(MC)/CDMA system is considered to mitigate multiple access interference, partial-band interference and enhance system channel capacity in wireless channel. Recently, to increase the spectrum efficiency and the link reliability, MIMO-MC/CDMA scheme is devised to exploit multi-path in a scattering wireless channel. In particular, the channel capacity of MIMO-MC/CDMA system is evaluated according to Eb/No. Mc, p and B. From the results, in order to inappropriate spacing and the signals are frequency overlapped by partial band interference, the channel capacity of MIMO-MC/CDMA system becomes substantially smaller.