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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
Editor in Chief :
Volume & Issues
Volume 19, Issue 4 - Dec 1997
Volume 19, Issue 3 - Oct 1997
Volume 19, Issue 2 - Jul 1997
Volume 19, Issue 1 - Apr 1997
Volume 18, Issue 4 - Jan 1997
Selecting the target year
CDMA Mobile System Overview: Introduction, Background, and System Concepts
Han, Young-Nam ; Bahk, Hang-Gu ; Yang, Seung-Taik ;
ETRI Journal, volume 19, issue 3, 1997, Pages 83~83
The CDMA Mobile System (CMS) has been developed by Electronics and Telecommunications Research Institute (ETRI) and field-tested for commercial service deployment in Korea. The project was started in 1989 and completed in 1995 with the CMS commercial test. During the course of development, there had been active technical cooperation with Qualcomm, Inc. and Korean manufacturers. The CMS adopted the basic CDMA concepts conforming to Korean CDMA system which was derived form IS-95. The CMS functions are allocated to subsystems by considering efficiency and expandability. The CMS consists of mobile stations and the infrastructure which is composed of base stations, mobile exchanges and home location register/authentication center. The commercial field tests performed both in Taejon and Seoul have indicated that the CMS capacity is 10 to 15 times larger than that of AMPS. This paper overviews the development history, system characteristics, architecture and test results.
The CDMA Mobile System Architecture
Shin, Sung-Moon ; Lee, Hun ; Han, Ki-Chul ;
ETRI Journal, volume 19, issue 3, 1997, Pages 98~98
The architecture of the CDMA mobile system (CMS) is developed based on three function groups - service resource, service control, and service management groups. In this paper, the CMS architecture is discussed from the point of view of implementing these functions. The variable length packets are used for transmission. The synchronization clock signals are derived form the GPS receiver. The open loop and closed loop techniques are used for the power control. The internationally accepted signaling and network protocols are employed. The call control for the primary services in designed to provide efficient mobile telecommunication services. The softer handoff is implemented in one card. The mobile assisted handoff and the network assisted handoff are employed in the soft and hard handoffs. The authentication is based on the secret data which includes random numbers. The management functions, which include the location management, resource management, cell boundary management and OAM management, are implemented to warrant the system efficiency, maximum capacity and high reliability. The architecture ensures that the CMS is flexible and expandable to provide subscribers with economic and efficient system configuration. The dynamic power control, adaptive channel allocation. and dynamic cell boundary management are recommended for future work.
Development of the Base Station Transceiver Subsystem in the CDMA Mobile System
Lee, Dong-Wook ; Yoo, Ki-Suk ; Kim, Jin-Su ; Kim, Myoung-Jin ; Park, Jae-Hong ;
ETRI Journal, volume 19, issue 3, 1997, Pages 116~116
The base station transceiver subsystem (BTS) of the CDMA Mobile System is interfaced to mobile stations over the air and to the wired network through a packet switched interconnection network. The potential benefits of CDMA technology are achieved when the transmitter and the receiver are properly designed and implemented. The physical layer of the interface at the base station is implemented with the CDMA ASICs and control circuits in channel card of the BTS. We present the design perspectives and structural illustration of the BTS. Base station modem ASICs and their control to implement the CDMA receiver, Baseband and RF signal processing blocks, and BTS controller are described. Elaborate power control is essential to ensure the high capacity which is one of advantages of the CDMA technology. The closed loop reverse link power control and the forward link power control operated in the BTS are described.
Development of the Base Station Controller and Manager in the CDMA Mobile System
Ahn, Jee-Hwan ; Shin, Dong-Jin ; Cho, Cheol-Hye ;
ETRI Journal, volume 19, issue 3, 1997, Pages 141~141
The base station (BS) in the CDMA Mobile System (CMS) connects calls through the radio interface and is designed to provide mobile subscribers with high quality service in spite of mobile subscribers motions. The BS consists of multiple base station transceiver subsystems (BTSs), a base station controller (BSC) and a base station manager (BSM). This paper is concerned with the BSC and the BSM. The BSC is located between the BTSs and the mobile switching center (MSC) connected with the public network, and to mobile subscribers via the BTSs. The BSM provides operator-interfaces per the BS and takes responsibility of operation and maintenance (OAM) of the BS. Design of the BSC is based on two module types: functional module and unit module. The functional module is used to support new services easily and the unit module to increase the system capacity economically. Both modular types are easily achieved by inserting the corresponding modules to the system. Particularly, in order to efficiently support the soft handover which is one of CDMA superior advantages, the BSC adopts a large high-speed Packet switch connecting up to 512 BTSs, and thus mobile subscribers can be provided with soft handover in high probability. The BSM is based on a commercial workstation to support OAM functions efficiently and guarantee high reliability of the functions. The BSM uses graphical user interface (GUI) for efficient OAM functions of the BS.
Development of the Mobile Exchange in the CDMA Mobile System
Lee, Chung-Kun ; Jeon, Hak-Seong ; Cho, Kee-Seong ; Lee, Sang-Ho ;
ETRI Journal, volume 19, issue 3, 1997, Pages 169~169
This paper presents the design concepts and the system architecture of a mobile exchange for CDMA Mobile System. The paper also discusses complex subsystems in this system and design concepts of these subsystems. To evaluate the performance of the CDMA Mobile System, we have performed a computer simulation based on the framework of the mobile exchange. Simulation results are presented in terms of network traffic load (call attempts per second) and database performance requirements (transactions per second.)
Development of the Home Location Register/Authentication Center in the CDMA Mobile System
Lim, Sun-Bae ; Shin, Kyeong-Suk ; Kim, Hyun-Gon ;
ETRI Journal, volume 19, issue 3, 1997, Pages 186~186
In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.
Development of Mobile Station in the CDMA Mobile System
Kim, Sun-Young ; Uh, Yoon ; Kweon, Hye-Yeoun ; Lee, Hyuck-Jae ;
ETRI Journal, volume 19, issue 3, 1997, Pages 202~202
This paper describes the development of the CDMA mobile station to support non-speech, mobile office services such as data, fax, and short message service in addition to voice. We developed some important functions of layer 2 and layer 3. To provide non-speech services, we developed a terminal adapter and user interface software. The description of development process, software architecture and external interfaces required to provide such services is given. The description of a TTA-62 message analysis tool, a mobile station monitoring software, and an automatic test system developed for integration tests and performance measurements is also given.
Design of Chip Set for CDMA Mobile Station
Yeon, Kwang-Il ; Yoo, Ha-Young ; Kim, Kyung-Soo ;
ETRI Journal, volume 19, issue 3, 1997, Pages 228~228
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
which is fabricated using a
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 (
) RAM, and 240k (
) ROM. The die size is
and chip is fabricated using
Fixed Point Implementation of the QCELP Speech Coder
Yoon, Byung-Sik ; Kim, Jae-Won ; Lee, Won-Myoung ; Jang, Seok-Jin ; Choi, Song_in ; Lim, Myoung-Seon ;
ETRI Journal, volume 19, issue 3, 1997, Pages 242~242
The Qualcomm code excited linear prediction (QCELP) speech coder was adopted to increase the capacity of the CDMA Mobile System (CMS). In this paper, we implemented the QCELP speech coding algorithm by using TMS320C50 fixed point DSP chip. Also the fixed point simulation was done with C language. The computation complexity of QCELP on TMS320C50 was 10k words and data memory was 4k words. In the normal call test on the CMS, where mobile to mobile call test was done in the bypass mode without double vocoding, mean opinion score for the speech quality was he Qualcomm code excited linear prediction (QCELP) speech quality was 3.11.
CDMA Mobile System Testbed and Field Test
Kwon, Dong-Seung ; Hahm, Young-Kwon ; Jeong, In-Myoung ; Im, Duck-Bin ;
ETRI Journal, volume 19, issue 3, 1997, Pages 259~259
This paper briefly explains the configuration of CDMA Mobile System (CMS) test bed. The measured fading and delay results of CDMA signal in Taejon area are shown. In comparison to other cellular systems, there are more parameters in the CDMA systems that affect system performance and capacity. We performed the optimization test of the selected parameters and present the effect of each parameter on the performance. This paper presents the capacity and performance test results of CMS. The capacity test was performed on ETRI site of three sectors in Taejon area. The performance tests include call completion rate, busy hour call attempt, and the delay characteristics of voice.
Development of the Test and Evaluation Systems for the CDMA Mobile System
Kang, Chang-Soon ; Lee, Nam-Jun ; Lee, Sang-Cheon ; Lee, Kyoung-Joon ; Kim, Ki-Hong ; Im, Duk-Bin ;
ETRI Journal, volume 19, issue 3, 1997, Pages 281~281
In this paper, we present three kinds of development support systems (test and evaluation systems), which are developed to fulfill the specific needs in accordance with the CDMA Mobile System (CMS) developmental phases. The support systems consist of the mobile switch traffic simulator (MSTS), the mobile call simulator (MCS), and the CDMA mobile system analysis tools (CSAT). The MSTS is used for the simulation of the base station in the stage of development of the mobile exchange, and the MCS is used for the overall performance test of the CMS. The CSAT is used for the CMS performance evaluation. These systems have been used for the CMS development successfully.
Investigation of CDMA Air Interface and Protocols
Kim, Sun-Young ; Song, Pyeong-Jung ; Kim, Jin-Up ; Lee, Hyuck-Jae ;
ETRI Journal, volume 19, issue 3, 1997, Pages 303~303
This appendix deals with the Korean air interface standard, TTA-62, for CDMA Mobile Systems, (CMS) -. The standard has been set up by Telecommunications Technology Association (TTA) which is a standardization organization in Korea . This standard is an important specification that should be determined prior to the development of a digital cellular system. The CMS has been developed on the basis of this standard and the papers published in this special issue are the results of the CMS development. This appendix also describes the technical commonality of these papers. It covers the outline of the air interface and protocol specifications. The outline includes its major characteristics, radio protocol architecture, functionalties, and call processing. A comparison is also given between TTA-62 and IS-95, a North American digital cellular standard.