• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.21-30
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• 2004

The capacity of WCDMA TDD system is limited mainly by the interference. So, to achieve the expected performance of WCDMA TDD system and to minimize the interference to cdma2000 system interferences, such as interference within WCDMA TDD system inter-cell interference, and interferences between cdma2000 systems, should be considered carefully. In this paper, by using System-level Simulation, we analyzed the interferences between WCDMA TDD system and cdma2000 system in practical situation based on the exact parameters of 3GPP TR 25.942 and by using System-level Simulation considering Link-level we analyze the interferences between WCDMA TDD system and cdam2000 system. From Simulation Results, we propose the condition for optimizing system capacity considering the interferences between WCDMA TDD system ＆ cdam2000 system

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.920-929
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• 2004

Nowadays, wireless packet data services are provided over cdma2000 1x/1xEV-DO mobile communication network and Portable Internet are being standardized for users demanding higher data rate services. Portable Internet can provide high data rate services, but its service coverage is relatively small. If Portable Internet may be integrated with cdma2000 mobile networks, users are able to choose the best service according to service areas and get seamless services while they are moving around. At the same time, it is cost-effective for operators to construct and maintain the integrated network. For the purpose of effectively integrating Portable Internet into cdma2000 networks, we propose an integration scheme including network architecture, protocol architecture, functions in network elements, interfaces between them, and call-flow procedures. The integration scheme proposed in this paper adopts a tightly-coupled architecture for unified authentication/accounting and seamless services. In addition, the scheme can be implemented without modifying the existing cdma2000 mobile communication networks. It is also simple to develop the dual-mode mobile station. Through the simulation results based on the performance model for handoffs between cdma2000 and Portable Internet, it has teen validated that the proposed scheme diminishes packet losses compared with the loosely-coupled architecture.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.128-137
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• 2006

Recently, the combination of WLAN and 3G wireless technologies will make MMS service more ubiquitous, bringing benefits to both service providers and their customers. To realize seamless MMS service over WLAN and CDMA2000 networks, we design novel seamless interworking architecture by reusing the existing standards and network elements at the same time. Based on the proposed seamless interworking architecture, we also present seamless notification architecture and seamless handover architecture that can't be possible within current MMS reference architecture. This paper will make a contribution for service providers to provide their customers with seamless MMS service over WLAN and CDMA2000 networks.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1536-1543
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• 2000

In this paper, we propose a multiple access scheme for efficient transmission of realtime and non-realtime data in IMT-2000 through cdma2000's CDMA MACD. On the contrast to the conventional circuit-based service, this framework is packet-oriented service. maximum number of simultaneous subscribers increases due to the statistical multiplexing based on variable transmission rate of realtime data. System performance is evaluated and compared with conventional circuit-based scheme considering transmission delay and channel utilization by computer simulation.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.221-223
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• 2005

In a CDMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power. The capacity of CDMA2000 1x system is considered to be limited by the forward link capacity. Different rate data traffic requires different transmitted power and rate controlling enables the system utilize radio resource more efficiently. A very simple rate control algorithm fer data calls in CDMA2000 1x system is proposed. In the proposed algorithm, by monitoring the total transmit power, we can simply adjust data rate to channel conditions and efficiently use radio resources. The proposed algorithm is easy to implement in power controlled CDMA systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.912-918
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• 2003

In this paper, we designed and implemented the dual band monopole antenna for cellular CDMA(Code Division Multiple Access) and IMT-2000(International Mobile Telecommunication 2000) repeater. The antenna was designed by using 3D simulations program, HFSS(High Frequency Structure Simulator). Electrical characteristics were measured by using HP 8720C network analyzer and measured maximum S$\_$11/ was -10.9 dB for all frequency bands of interests in Cellular CDMA and IMT-2000. Simulation results for antenna gain at 859 MHz and 2027.5 MHz were 2.38 dBi and 4.02 dBi respectively with omni directional radiation pattern. The size of implemented antenna is compact and the antenna can be produced in low cost enough for commercialization.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.2
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• pp.75-82
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• 2000

In this paper, described is the comparison of performances based on the computer simulation under IMT-2000 environment between multicode and multicarrier CDMA system for the design of wireless systems using wideband CDMA technology. From simulation results, it can be concluded that both multicode and multicarrier CDMA scheme show comparable performances. Diversity scheme of RAKE receiver is indispensible for both multicode and multicarrier CDMA systems under IMT-2000 outdoor B and vehicular B channel environment. Either Hadamard matrix or PN sequence can be used as the orthogonal code as far as the orthogonality is kept. Finally, with increasing chip rate and less users, performance is getting better.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.313-322
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• 2003

In this paper, the reverse link performance of imperfect power controlled cdma2000 cellular system that using array at a base station is analyzed, when MCGM beamforming algorithm and power control error is considered in shadowing. The blocking probability of the cdma2000 cellular system based on array parameters, E$\_$b//N$\_$0/ and interference statistics is calculated, and then the system capacity is calculated at a specific blocking probability. When the blocking probability is set 1 %, PCE(power control error) is 2 dB, M=2, 4, 8, 10, the capacity of cdma2000 is increased 2.3 ∼ 2.5 times higher than IS-95.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4B
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• pp.183-190
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• 2007

The cdma2000 mobile network covers a wide area but its characteristics are high cost and low bandwidth. On the other hand, WLAN covers a small area like a hot spot area but its characteristics are large bandwidth and low cost. Thus we can provide efficient services when we employ an integration network between WLAN and cdma2000 mobile networks. In this paper, we propose an integration scheme between WLAN and cdma2000 mobile networks. In addition, we design and implement the dual mode terminal which receives seamless data services in the integrated network. The proposed dual mode terminal manages connections by monitoring the signal strength of WLAN and selecting a proper network. We validate the functions through the implementation of VOD and show the effectiveness through the performance measurement.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.873-880
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• 2006

Since various networks are deployed and the most of users request higher mobility, there are many researches about the interworking between widely deployed 3G network and rapidly boarded WLAN. On the other side, WiBro is focused on as a next generation network, because many people expect that WiBro gives satisfaction about the enough mobility and mass data transmission. So the study of the integration between WiBro and cdma2000 will show better effects than the present study of the integration between WLAN and cdma2000. The L2 handoff proposed in this paper takes advantages over the existing L3 handoff scheme because it does not require the L3 procedure for the mobility unlike the L3 handoff. Through extensive computer simulations, the efficiency of the proposed scheme has been validated.