• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.1343-1345
• /
• 2002

In this paper, we introduce the MC-CDMA (Multi-Carrier CDMA) system with MD (multi-detector). Due to unknown functional form of noise in wireless channel environments, it is not easy to design the detector through estimating the functional form of noise. Instead, we design the MD, which is constructed based on DGT (Data Grouping Technique) and quantiles estimated through RMSA (Robbins-Monro Stochastic Approximation) algorithm.

• ETRI Journal
• /
• v.25 no.6
• /
• pp.523-526
• /
• 2003

This letter presents an approximation of the outage probability of the pilot channel that can be used for CDMA cell planning. The approximation can determine system parameters for soft handover in IS-95-based cellular CDMA downlink design. Computer simulations show that our analytical results agree with empirical results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.9A
• /
• pp.1368-1376
• /
• 2000

This paper describes the codesign method for IS-95 based CDMA(Code Division Multiple Access). By codesign we mean to design hardware and software simultaneously. Codesign lead to reduction in design time, cost and power consumption. When we partition a system into hardware and software, some modules with longer processing time and larger power consumption are implemented using hardware and the remaining part is implemented using software. In proposed design, we design the synchronous accumulator of CDMA searcher in hardware and the other part in software, The hardware part is designed using VHDL, while software part is designed using GC(Generic C). We simulated and verified the system using COSSAP in SYNOPSYSTM. Experimentation showed the maximum 48.5% speed reduction compared with the design using software only.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.1 s.45
• /
• pp.155-160
• /
• 2007

Because output of multi-code CDMA system adapted high speed data transmission becoming multi-level system use linear amplifier in output stage and complex output signal. Therefore, Multi-Code CDMA system has shortcoming of high price, high complexity etc.. Binary CDMA technology that allow fetters in existing CDMA technology to supplement this shortcoming proposed. In binary CDMA system When correlator process high speed data, bottle-neck phenomenon is happened on synchronization acquisition process, it is very important parameter. Because existent correlator must there be advantage that power consumption is small but flow addition of several stages to receive correlation's value, the processing speed has disadvantage because the operation amount is much. Therefore in this paper, proposed correlator has characteristic such as data is able to high speed processing, chip area is independent and power consumption is constant in structure in binary CDMA system.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.3 no.3
• /
• pp.177-182
• /
• 2008

Because output of multi-code CDMA system adapted high speed data transmission becoming multi-level system use linear amplifier in output stage and complex output signal. Therefore, Multi-Code CDMA system has shortcoming of high price, high complexity etc. Binary CDMA technology that allow fetters in existing CDMA technology to supplement this shortcoming proposed. In binary CDMA system When correlator process high speed data, bottle-neck phenomenon is happened on synchronization acquisition process, it is very important parameter. Because existent correlator must there be advantage that power consumption is small but flow addition of several stages to receive correlation's value, the processing speed has disadvantage because the operation amount is much. Therefore in this paper, proposed correlator has characteristic such as data is able to high speed processing, chip area is independent and power consumption is constant in structure in binary CDMA system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.6A
• /
• pp.425-432
• /
• 2003

In this paper, we designed a multi-carrier digital transmitter for CDMA base-station using a direct conversion scheme and verified the performance through circuit simulations. We examined a new technology required to design a multi-carrier transmitter, then designed and simulated a multi-carrier digital transmitter. ADS (Advanced Design System), RF simulation S/W of Agilent Technologies, was used for designing and simulating the multi-carrier digital transmitter. First, we simulated a digital block and an analog block separately, then performed a co-simulation for entire system. From the results, the final analog outputs of the designed multi-carrier digital transmitter met the spectrum mask characteristics of IS-97 & 3G TS 25.104 standard requirements. It means that proposed scheme could be applied to implement a multi-carrier digital transmitter for CDMA base-station. Therefore, proposed multi-carrier digital transmitter using a direct conversion scheme can accomplish cost-reduction and improvements of technology in the next CDMA base-station.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.10
• /
• pp.72-79
• /
• 1996

We developed a speech coder that can transfer data as well as speech for CDMA digital cellular system. We describe the design method of the speech coder that uses QCELP algorithm for speech coding. The speech coder is implemented on a single fixed-point DSP chip (TMS320C50). the coder has the complexity such as 4K words in RAM, 10K words in ROM, and 33 MIPS in execution time. The developed speech coder is fully tested and successfully working on the CDMA base station system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.6A
• /
• pp.397-404
• /
• 2003

In this paper, we have analyzed the level of cross-modulation noise required for CDMA mobile station and proposed a guideline for optimum design. From the analysis, the level of cross-modulation noise is determined by the system's noise figure(NF) and VCO's phase noise and there is a trade-off relationships between them. In addition, we have determined the value of LNA's IIP3 and duplexer's isolation to satisfy the above level in designing the system. Therefore, this paper will give a guideline for a selection of components in designing cdma2000 mobile station.

• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.433-436
• /
• 2000

In this paper, capacity of a multicarrier DS/CDMA system is analyzed and simulated in a Nakagami fading channel. It is confirmed that the adaptive antenna array is a very efficient solution to enhance system capacity of a multicarrier DS/CDMA system. The results in this paper can be applicable to receiver design for the third and fourth mobile communication systems.

• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.69-70
• /
• 2007

The code division multiple access (CDMA) system capacity is limited by the amount of interference of the system. To reduce the unnecessary interference, this paper proposes optimized cell identification (ID) codes for site selection diversity transmission (SSDT) power control in wideband code division multiple access system of third generation partnership project (3GPP). The proposed SSDT cell ID codes are designed to minimize the problem and to be easily decoded using simple fast Hadamard transformation (FHT) decoder.