• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1422-1430
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• 2000

S(Synchronous)-CDMA is a new cable modem technology applicable to the upstream channel for high speed multimedia communication using CATV networks. In this paper we analyze the transmitting and receiving process of S-CDMA scheme based on Terayon patent and derive bit error probability of S-CDMA and TDMA scheme in the $\varepsilon$-mixture impulse noise model which appropriately reflects impulse noise characteristics of upstream channel by using various parameters. This analysis results are a good match with the simulation results. We also compare Eb/No gain performance of S-CDMA with TDMA in 16, 32, 64, QAM.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.220-229
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• 1996

We presetn sytem-level simulation methodology as well as environment setup established for CDMA digtial cellular mobile station in an effort to verify CDMA modem ASIC design. To make the system-level simulation feasible, behavioral modeling of a microcontroller was first carried out with VHDL. In addition, models written in C language were also developed to provide ASIC with realistic input data. Finally, the netlist of CDMA modem ASIC was loaded on the a hardware accelerator, which was interfaced with VHDL simulator, and ismulation was performed by excuting the actual CDMA call processing software. Simulation resutls thus obtained were confirmed by comparing them with the emulation resutls from the actual system constructed on hardware modeler. these methods were proved to be effective in both discovering in advance malfunctions when embedded in the system or design errors of ASIC and reducing simulation time by a factor of as much as 20 in case of simulation at gate-level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.921-927
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• 2006

The current DGPS technique is many problems that is permission of radio station using RF Wireless Modem, that is influence of geographic obstacle using radio wave, that is frequency interference, that is finiteness of frequency resources. In this paper, we are solved many elements, IM(Interface Module) replaces RF Wireless Modem, we suggest transmission technique of correction message using mobile phone, we researched Interface Module development which is linkage of DGPS receiver and mobile phone. IM can transmit correction message passing RS-232 port and modem communication control. IM of base station is initialized RS-232 port and modem to move station for correction message transmission, IM waited response mode. IM of move station is initialized RS-232 port and modem, IM requests hand shaking to base station, completed connection establishment. Users are worked Differential surveying using receiving correction message between mobile phones.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.69-77
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• 2002

In this paper, we present the CDMA2000 1x compliant mobile station modem chip (SCom5010) implemented in a 0.18${\mu}{\textrm}{m}$ CMOS technology.[1] ARM940T cached processor. TeakLite DSP core, and other peripheral blocks are integrated with the baseband modem chip. Also we show novel verification methodologies and explain how this chip can be used as an emulation processor.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.351-359
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• 2012

This paper deals with the design and development of the remote control and measurement systems using CDMA(Code Division Multiple Access) data modem. We propose a bi-directional data communication link without the public IP address in CDMA modem device by the TCP/IP packet and SMS(Short Message Service) communication. The remote control and measurement systems are implemented by a Telit WM-800 modem as DCE(Data Communication Equipment), and Atmel AT89C51 microcontroller as DTE(Data Terminal Equipment). The user application software for the control and measurement system user, and the firmware software of device drivers for peripherals such as a digital input/output device, AD/DAC(Analog to Digital/Digital to Analog Converter), LCD, and temperature/humidity sensor are written in Microsoft C and Keil C language respectively for further various applications. The experimental result of the proposed control and measurement systems implemented in this paper is evaluated via real-time experiments, which works well as designed.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.77-80
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• 2000

In this paper, we implemented the voice modem using the multicarrier DS-CDMA in powerline channels. Both TMS320C5402 of Texas Instrument and FPGA FLEX 10K EPF10K100ARC240 of ALTERA are used to realize the proposed system. For robustness in the powerline channel, we used multicarrier DS-CDMA modulation, convolutional encoding/Viterbi decoding, and interleaving. Finally, we showed satisfactory performance in the laboratory experiment.

• ETRI Journal
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• v.19 no.3
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• pp.228-241
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• 1997

In this paper, we present a design of modem and vocoder digital signal processor (DSP) chips for CDMA mobile station. The modem chip integrates CDMA reverse link modulator, CDMA forward link demodulator and Viterbi decoder. This chip contains 89,000 gates and 29 kbit RAMs, and the chip size is $10 mm{\times}10.1 mm$ which is fabricated using a $0.8{\mu}m$ 2 metal CMOs technology. To carry out the system-level simulation, models of the base station modulator, the fading channel, the automatic gain control loop, and the microcontroller were developed and interfaced with a gate-level description of the modem application specific integrated circuit (ASIC). The Modem chip is now successfully working in the real CDMA mobile station on its first fab-out. A new DSP architecture was designed to implement the Qualcomm code exited linear prediction (QCELP) vocoder algorithm in an efficient way. The 16 bit vocoder DSP chip has an architecture which supports direct and immediate addressing modes in one instruction cycle, combined with a RISC-type instruction set. This turns out to be effective for the implementation of vocoder algorithm in terms of performance and power consumption. The implementation of QCELP algorithm in our DSP requires only 28 million instruction per second (MIPS) of computation and 290 mW of power consumption. The DSP chip contains 32,000 gates, 32K ($2k{\times}16\;bit$) RAM, and 240k ($10k{\times}24\;bit$) ROM. The die size is $8.7\;mm{\times}8.3\;mm$ and chip is fabricated using $0.8\;{\mu}m$ CMOS technology.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.107-114
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• 2004

In this paper, we present the architecture design of CDMA/TDMA modem chipset for wireless telemetry system. The wireless telemetry system a measuring data collecting system from many RTs(Remote Terminal) installed at the specific area using wireless communication technology. It consists of CU single CU (Central Unit) for collecting data and a large amount of RTs for transmitting the measuring data. We propose the hardware architecture of the modem for RT and CU. We also design those modem using Verilog HDL and synthesis them using Synopsys$^{TM}$ CAD tool. The modem of RT is implemented with 27K gates and that of CU is implemented around 220k gates using 0.6${\mu}{\textrm}{m}$ CMOS standard cell. The proposed system is implemented and tested using Altera$^{TM}$ FPGA.PGA.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.1-6
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• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.11-14
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• 2010

In this paper, an improved binary-CDMA (Code Division Multiple Access) system for high speed multimedia data transmission will be presented. The improved binary CDMA technology will be used in municipal wireless network. The new name of the system is the Guardian system using a binary CDMA technology. The Guardian system can provide high data rate, and improve its throughput by minimizing latency from the limitation of resources of system bus during multimedia data transmission. Finally, we analyze the performance of Guardian modem according to the report of wireless data transmission test.