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FSTJ 2002-12 Cover Image

2002-12 (Vol.38, No.2)

Fujitsu's IT (information technology) merged with wireless communications creates ubiquitous networks at home and in society. Here, we introduce the major technologies in the realization of International Mobile Telecommunication-2000 (IMT-2000).

2002-12 (Vol.38, No.2) Contents

1. Preface (24 KB)
This issue will provide you with some exciting visions of the coming IT society. ---[Hiroaki Takeichi, Corporate Vice President & Group President,Network Systems Group. ]
2. Fujitsu's Challenges in Wireless Communications (164 KB)
This paper describes the challenges that Fujitsu is taking up in wireless communications and reviews Fujitsu's development history in the first, second, and third generation of cellular systems. Fujitsu is a total-system vendor of services, information, networks, and devices that derives its strength through inter-division collaboration. At the advent of 3G, Fujitsu established itself as a total-system vendor of mobile communications and started to deliver the major 3G components, for example, handsets, base transceiver stations (BTSs) , radio node controllers, multimedia processing equipment, and multimedia mobile switches, to its customers. Through the development of this equipment, many technological breakthroughs have been made. Fujitsu has developed a W-CDMA power amplifier that has the highest efficiency in the world. This achievement is a testament to Fujitsu's expertise in semiconductor fabrication, digital signal processing, equipment technologies, and many other technologies. This paper also looks at the speed and complexity of digital signal processing that will need to be achieved and the trends of software defined radio (SDR), which along with the expected progress in semiconductor fine-process technology will determine the specifications for the next-generation mobile system. Finally, this paper describes the future network with which a ubiquitous communication society will be realized. ---[Takeshi Takano, Hirohisa Gambe, Tsuguo Katoh]

Mobile Network Technologies

3. IMT-2000 Network Architecture (63 KB)
International Mobile Telecommunication-2000 (IMT-2000) is a third-generation mobile communication system. It has been established as an international standard to realize advanced services and also overcome the performance limitations of the telephone and data communication services that are based on existing second-generation mobile communication systems (i.e., Personal Digital Cellular [PDC], cdmaOne, and Global Systems for Mobile communications [GSM]). This paper outlines the services recommended in IMT-2000 and describes the base station systems, switching systems, and various servers of the IMT-2000 network architecture. This paper also describes the packet processing mechanism and the techniques for constructing IMT-2000 networks. Finally, this paper describes the technologies related to intelligent networks (IN), which provide additional, highly advanced services. ---[Toshio Shimoe, Takamichi Sano ]
4. Overview of Mobile Network Services and Service Control Technologies for Future Enhancements of IMT-2000 (90 KB)
This paper looks at the trends in mobile communication services in Japan and proposes several service control technologies of Fujitsu and an example service for mobile users. In Japan, some of the major mobile network operators have launched IMT-2000 (Third-generation mobile) services. These services provide users with phone services having superior voice quality and faster data communications than existing second-generation infrastructures. This paper introduces services and products that exploit the capabilities of IMT-2000 and looks at the activities of network operators and service providers. This paper also proposes several of Fujitsu's service control technologies for future mobile communication systems and a service that uses these technologies to provide company users with a secure network access service over a VPN (Virtual Private Network). ---[Mitsuaki Kakemizu, Yoichiro Igarashi]

Radio Access Network

5. Radio Access Technologies and Signaling Scheme in W-CDMA System (76 KB)
W-CDMA is a radio interface for IMT-2000 (International Mobile Telecommunications-2000), which was standardized for use as the 3rd generation wireless mobile telephone system. W-CDMA provides a voice service whose quality is comparable with that of a fixed public telephone network and also multimedia mobile communication services with global roaming capability. This paper introduces the radio access technologies and signaling scheme of the W-CDMA system, which Fujitsu has been working on with the 3GPP community to achieve a competent and feasible system. First, this paper gives a brief description of Layers 3 and 2 of the radio interface protocol. Then, it describes some of the essential aspects of the Layer 1 radio interface in frequency division duplex (FDD) mode, for example, the physical channel structure and transmitting power control method. Finally, this paper gives an overview of the HSDPA (High Speed Downlink Packet Access) scheme, which has been introduced into the latest releases to enable up to 10 Mb/s transmission. ---[Takaharu Nakamura, Kazuhisa Ohbuchi,Yoshiharu Tajima, Tetsuya Yano, Yoshinori Tanaka ]
6. Network Node for IMT-2000 (67 KB)
Fujitsu has developed a Mobile Switching Node for IMT-2000 3G Networks. This system is an extended version of the GSM/GPRS. It can offer an efficient and flexible service by integrating the circuit switching function and packet switching function based on ATM technology. The software of this system has a hierarchical layer configuration. This paper outlines the new hardware and software architecture of this Mobile Switching Node system and its high performance, high reliability, and high expandability.---[Kenya Tanaka, Mitsuyuki Mizuno, Kazuhiro Sato ]
7. Base Transceiver Station for W-CDMA System (152 KB)
In January 2001, Fujitsu started commercial delivery of a W-CDMA base transceiver station (BTS). We then dramatically increased the number of traffic channels in this BTS and reduced its power consumption. Then, in September 2002, we began mass production and delivery of the new, large-capacity BTS. This equipment conforms to the global standard specifications of the 3GPP (3rd Generation Partnership Project) and was developed using all of Fujitsu's expertise, for example, expertise in radio technology, network technology, and electronic device technology. This paper gives an overview of this large-capacity BTS and introduces its features. ---[Satoshi Maruyama, Katsuhiko Tanahashi, Takehiko Higuchi ]
8. Radio Network Control System (105 KB)
Our radio network control system based on the W-CDMA global standard specifications of the 3GPP (3rd Generation Partnership Project) can provide multimedia services such as voice, TV telephone, packet, and multi-call at a higher quality and higher rate than those of the 2nd generation mobile telecommunication system. Our radio network control system has a highly flexible and scalable structure. This has been achieved by dividing various functionalities such as diversity handover, common transport channel related transaction, user data transaction with protocol conversion, and bandwidth control based on ATM and other technologies into several transaction units. These transaction units use high-speed RISC processors and closely interact with each other under the control of the application part to achieve various high-performance functionalities. This paper describes the architectures, functionalities, and technologies of our radio network control system. ---[Kenichi Ito, Tomonori Kumagai, Kenichi Harada, Takashi Sonobe, Tetsuo Tomita, Eiji Ikeda ]
9. Modified Stochastic Knapsack for UMTS Capacity Analysis (69 KB)
This paper is a brief introduction to the complex task of UMTS (Universal Mobile Telecommunications System) network dimensioning, with emphasis on capacity analysis and the innovative solution developed by FLE for this purpose. Capacity analysis (an integral part of dimensioning) is a study that allows the estimation of required resources that can guarantee a defined level of satisfaction for the users. Compared to fixed and 2G mobile networks, this task is much more challenging in 3G systems due to two main reasons. First is the fact that the cell edge in UMTS is continuously moving according to the traffic load, making dimensioning ambiguous and leaving room for under or over dimensioning. The second challenge is an outcome of the multiple data rates and switching modes supported by the 3rd generation networks. Traffic and capacity analysis for such mixed services is a new concept which was addressed by Fujitsu by the use of a modified Stochastic Knapsack traffic model. The Stochastic Knapsack is a multi service traffic model by definition and is generally used in ATM multiplexer dimensioning. This paper introduces the steps involved in UMTS air interface dimensioning and describes in detail how the basic stochastic knapsack was modified to provide a traffic model that captures the peculiarities of UMTS traffic. ---[Mona Jaber, Syed Ammar Hussain, Adel Rouz ]

Advanced Technologies

10. Adaptive Array Antenna for W-CDMA Systems (94 KB)
The adaptive array antenna (AAA) is one of the advanced techniques that will be implemented in the IMT-2000 mobile telecommunications systems to achieve a high system capacity. This paper describes an integrated AAA system for W-CDMA that consists of both uplink and downlink beam formers. We developed three functions for the AAA: a digital beam former using the normalized least mean square (NLMS) algorithm, a two-dimensional path searcher that works at a lower reception level than the conventional one, and a calibrator that compensates for variations in the amplitude and phase of signals at antenna branches. We built an experimental test bed, conducted field trials, and evaluated characteristics of the AAA such as the compensation accuracy of the calibrator and the path search sensitivity of the path searcher. The experimental results showed that the AAA is effective enough to improve system capacity. ---[Yutaka Yasui, Shuji Kobayakawa, Tadashi Nakamura]
11. Highly Efficient Power Amplifier for IMT-2000 BTS Equipment (152 KB)
IMT-2000 services are growing in Japan, and the demands for power-efficient and physically small base transceiver stations (BTSs) for IMT-2000 have become strong. One way to meet these demands is to reduce the power consumption and size of the large, high-power-consumption power amplifiers (PAs) that are currently being used in BTSs . We have therefore developed a new adaptive digital predistorter (DPD) and a multicarrier signal processing technique for reducing PA nonlinear distortion and have used it to build a new, highly efficient PA for IMT-2000 BTS equipment. The power efficiency of our new PA is double that of conventional PAs. We have already supplied customers in Japan and Europe with enhanced BTSs that contain our new PA. This paper describes these techniques for reducing PA nonlinear distortion and the performance of our new PA. ---[Yasuyuki Oishi, Norio Tozawa, Hiroshi Suzuki ]
12. Advanced Device Technologies for IMT-2000 Systems (334 KB)
In IMT-2000, the deployment of advanced device technology is the key factor for achieving various system requirements, for example, increasing the number of subscribers, high-speed transmission, efficient usage of battery power, and expanding the functionality. In this paper, we introduce our achievements in the development of advanced devices such as high-power GaAs FETs, small-volume SAW filters, and low-power baseband devices and in the development of a mobile multimedia platform. ---[Nobuhiko Aneha, Makoto Awaga, Yuji Segawa, Shoji Taniguchi, Yoshio Satoh, Hideki Yoshizawa, Hiroshi Nakayama, Kazutaka Inoue ]

Terminals and Their Element Technologies

13. W-CDMA Mobile Terminal (71 KB)
NTT DoCoMo, Inc. started its IMT-2000 mobile communication service last October. IMT- 2000, which uses the W-CDMA system, is a global standard of 3rd generation mobile communication systems. Fujitsu was selected to be one of the developers of IMT- 2000 together with NTT DoCoMo, Inc. in 1999 and since then has developed various commercial W-CDMA mobile terminals. We have pursued this development by drawing on our expertise in technologies such as radio, baseband signal processing, and hardware/firmware. One of the products of our development efforts, the FOMA F2611, is targeted for SOHO (Small Office Home Office) and was released in April. This paper introduces the FOMA F2611. ---[Hideto Furukawa, Yasunobu Watanabe, Mitsunori Maeda ]
14. Reduced Resolution Method: A Visual Signal Coding Technology for Mobile Communications (88 KB)
The videophone service has been a dream for a long time, but there have been several reasons that prevented the service from becoming a reality. These are 1) the available data transmission bit rates were not high enough, 2) there were no encoding algorithms suitable for error prone transmission environments, and 3) the signal processing power of LSIs was too low. However, with the start of third-generation mobile communication services and the development of relevant technologies, such obstacles have almost disappeared and products with videophone capability are already on the market. This paper describes a visual signal encoding algorithm that Fujitsu has developed for the MPEG-4 system and describes its effectiveness under error free and error prone conditions. On average, our algorithm showed a 1 dB higher picture quality and an 18% smoother motion compared to the simple MPEG-4. The new algorithm is called the reduced resolution method. ---[Takashi Itoh]


15. Overview of Global Standardization of IMT-2000 and Its Evolution (112 KB)
The fundamental objective of the standardization activities for International Mobile Telecommunication 2000 (IMT-2000) is to develop a globally unified standard to facilitate mobile multimedia services and global circulation of mobile terminals. To achieve this, the International Telecommunication Union (ITU) has been making extensive efforts over a long period. Also, technical forums such as the 3rd Generation Partnership Project (3GPP) and the 3GPP2 have been carrying out the pertinent practical work in close cooperation with other entities such as the Internet Engineering Task Force (IETF), the GSM Association (GSMA), and IPv6 Forum. This paper presents an overview of the global standardization activities for IMT-2000 and describes some of the contributions that Fujitsu has made during the standardization activities. Sections 1 to 3 describe the background of the 3GPPs. Sections 4 to 6 describe the scope and objectives of the 3GPPs, their organization, the specifications they have released, and the harmonization activities in the two groups. Section 7 describes Fujitsu's activities in the standardization process, and Section 8 looks at new features for enhancing the performance of systems beyond IMT-2000. ---[Eisuke Fukuda, Akishige Noda, Mamoru Higuchi ]