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This article was published in the April 1997 issue of
IEEE Personal Communications.

ABSTRACT

 

Personal communications services (PCS) is a set of capabilities that allows some combination of terminal mobility, personal mobility, and service profile management. In other words, PCS allows a person, by employing a unique personal number, to access telecommunications services anytime, anywhere, with the services controllable by the person himself or herself. PCS has been widely recognized as one of the most significant growth areas in telecommunications for the decade to come. This article summarizes the Directorate General of Telecommunications' (DGT) PCS development plan for Taiwan, Republic of China. Furthermore, PCS R&D activities in the Telecommunication Laboratories, a DGT research institute, are described in detail. Examples include the enhancement and evolution of cellular systems, intelligent networks for PCS, wireless access technology, field trials, propagation measurements and modeling, and RF technology.

 

 

Development of Personal Communications Services for Taiwan Areas

 

Mu-Piao Shih and Lir-Fang Sun, Chunghwa Telecom Co., Ltd.
Duei Tsai, Ministry of Transportation and Communications
Shyue-Ching Lu, Chunghwa Telecom Co., Ltd.

 

Personal communications services (PCS) is a set of capabilities that allows some combination of terminal mobility, personal mobility, and service profile management [1]. Terminal mobility refers to the ability of a terminal to access telecommunication services from different locations while in motion; personal mobility refers to the ability of a user to access telecommunications services at any terminal on the basis of a unique personal number; and services profile management refers to the ability of a user to access and manipulate the user's service profile. In other words, PCS allows a person, by employing a unique personal number, to access telecommunications services anytime, anywhere, and with services controllable by the person him- or herself. It has been widely recognized that PCS is one of the most significant growth areas in telecommunications for the decade to come [2–5]. In Taiwan, Republic of China (ROC), PCS has been listed as one of the telecommunication development projects under the Six-Year National Development Plan [6]. Since 1992, this project has been undertaken by the Directorate General of Telecommunications (DGT), the sole service provider of public telecommunications in Taiwan.
Telecommunication Laboratories (TL), a research institute of DGT, has two major fields of mission. One is to provide technical support for DGT, including network planning, new services creation, drafting various technical specifications, and so on. The other is to develop new technologies to help the local telecommunications industry. Hence, it is TL's responsibility to both define what should be Taiwan's PCS architecture and environment in the near future, and determine how to get there based on what Taiwan has now.
In this article, the DGT's PCS development plan is described first, including the status of today's paging and mobile services in Taiwan and the plan for evolving toward PCS. Second, recent PCS R&D activities in TL will be described in more detail; these include the enhancement and evolution of cellular systems, intelligent network (IN) technology for PCS, wireless access technology, field trials, propagation measurements and modeling, and radio frequency (RF) technology.

Paging and Mobile Communications Services in Taiwan

DGT introduced a tone-only paging system in 1980. It turned out to be a very popular service even though it is a unidirectional communication service only. The number of subscribers of paging systems has grown from 3000 in 1980 to 2,100,000 in 1995, a 700-fold growth in just 15 years. Meanwhile, the types of paging systems have evolved from tone-only systems to numerical systems to alphanumerical systems, including Chinese characters. Also, the service area has been enlarged from initial coverage of some isolated metropolitan areas to the whole area of Taiwan.
DGT introduced Advanced Mobile Phone Service (AMPS) in July 1989. The number of subscribers to this system is shown in Fig. 1. As can be seen, the growth rate was as high as 135 percent in 1992. However, since 1994 the rate has slowed down due to the difficulty of system expansion. Currently there are around 593,000 subscribers in this system, and most of them are using handheld telephones. At the moment, eight dedicated mobile switches and 304 base stations have been installed, covering 95 percent of the populated areas of the country.
Because of the rapidly increasing demand for mobile services, DGT decided in 1994 to deploy a Global System for Mobile Communications (GSM) digital cellular system. The first GSM system has a total capacity of 500,000 subscribers and is to be implemented in three phases. The first phase started service in July 1995 with a capacity of 200,000 subscribers; the second phase went into service in June 1996 with a capacity of 100,000 subscribers; and the third phase is scheduled to start in January 1997 with a capacity of 200,000 subscribers. As the fast-growing economy continues to flourish in the country, we estimate conservatively that the market potential of mobile users in the Taiwan area is approximately 1.3 million in 1997 and 2.5 million by the turn of the century. In order to meet the high growth rate, DGT is also planning to add a second GSM system with a capacity of 300,000, and introduce DCS-1800 before the entire GSM reaches full capacity.
In the long run, the AMPS system shall be upgraded from analog to digital. To make a graceful transition, DGT will make a choice between the two U.S. standards, IS-95 (code-division multiple access, CDMA) and IS-136 (time-division multiple access, TDMA), both dual-mode standards supporting analog and digital technologies.
In addition to paging and cellular services, a total of nine CT-2 licenses were granted in June 1995 to private operators who will, in turn, offer telepoint services in northern, southern, and central Taiwan, with three operators in each region. Cordless Telephone 2 (CT-2) is a low-power system to be used at home, on the street, and in the office, and allows for two-way calling. Due to its low cost and low airtime charge, CT-2 may soon grab its market share in the mobile communication business.

Evolution Toward PCS

As mentioned before, PCS is a set of capabilities that allows some combination of terminal mobility, personal mobility, and service profile management. That is, it emphasizes person-to-person rather than traditional point-to-point communication. In our opinion, ubiquitous PCS can be implemented only by integrating the wireless and wireline systems on the basis of IN, which provides network functions of terminal and personal mobility. Figure 2 is a PCS architecture or environment being considered at this time. As one can see, based on IN, this architecture consists of various access systems, including satellite communications systems, digital cordless systems, macro- and microcellular systems, paging systems, and wireline systems. DGT also believes that it is an evolutionary process to reach true ubiquitous PCS. Therefore, a step-by-step procedure has been adopted by DGT to approach this ultimate goal:
  • Enhancing the performance of the existing AMPS system
  • Deploying GSM and DCS-1800 systems to meet the increasing demand for mobile services
  • Evolving the analog AMPS by using new wireless technologies
  • Expanding paging capacity by using advanced paging systems
  • Deploying low-power wireless systems, such as Personal Access Communications System (PACS), which is a U.S. PCS standard, and Digital European Cordless Telecommunications (DECT), the European standard
  • Integrating IN and the existing wireline and wireless systems for ubiquitous PCS
The evolution of personal communications in DGT is depicted in Fig. 3. For seamless mobile communications, DGT also plans to participate in some global mobile satellite networks, such as LEO (low earth orbit) and MEO (medium earth orbit).
To realize the goal of PCS, wireline technologies will play a very important role in addition to wireless access technologies. The most significant technology for enabling PCS is probably the development of the fixed networks to which the wireless systems are interconnected. Since 1991, DGT has been continuously making efforts to digitize the wireline networks. In 1994, the overall digitization of this country's toll switching systems was completed. To pave the way for realizing a PCS environment, DGT has also evolved a plan for introducing intelligence into the wireline networks. We aim to establish a national CCS7 (Common Channel Signaling No.7) system by the end of 1998. On the other hand, we are expected to inaugurate Personal Number (PN) service in 1996. PN service will provide end users with personal mobility nation-wide over both wireline networks and the existing AMPS and GSM systems. Beginning with the PN service, the intelligent network will gradually evolve to provide other PCS capabilities.
Finally, following the international trend, the ROC will gradually open the telecommunication services market to the private sector. This deregulation process should stimulate market growth and make PCS a reality earlier.

Recent PCS-Related R&D Activities in the Telecommunication Laboratories

The Enhancement and Evolution of Existing Cellular Systems

Cellular systems play a very important role within telecommunication services. In Taiwan, cellular subscribers are increasing very rapidly. To provide better service quality, the performance of current AMPS and GSM systems should be improved continuously to meet customers' requirements. The followings are some of the efforts on enhancing these two systems and planning future new systems:
AMPS Fine Tuning -- As shown in Fig. 1, the number of the AMPS subscribers was around 560,000 in April 1994. Following the change of traffic demand, the system parameters needed to be adjusted to better meet the real requirements. In January 1994, TL cooperated with the Long Distance Telecommunication Administration (LDTA) to transact "fine tuning" to improve system performance. We finally expanded the AMPS system capacity by 30,000 and 10,000 in June 1994 and January 1995, respectively. The adjustments include RF transceiver reallocation, channel borrowing, antenna down tilt, handoff threshold adjustment, and switch parameter adjustment. Since then LDTA has undertaken the so-called quality improvement cycle to ensure service quality.
Deployment of Microcells -- Owing to the rapidly increasing of AMPS users, high traffic loads and blocking rate occurred in some busy cells. To relieve hot-spot traffic congestion and improve coverage in some dead spots, ten optical microcells have been deployed in metropolitan areas and some dead spots on a trial basis. Preliminary test results show that the microcell is efficient in enhancing capacity and coverage.
Coexistence of AMPS and GSM -- The new GSM system is engineered to be collocated with existing AMPS. The AMPS system operates in the 825–845 MHz and 870–890 MHz ranges. However, GSM operates in the 890–915 MHz and 935–960 MHz bands. Since these two frequency bands are adjacent, potential interference problems may occur between the two systems. Although 5 MHz guard band has been allocated between the frequency bands, a bandpass filter is also required in front of the GSM base station receiver to suppress the high-power emissions from AMPS transmitters. On the other hand, on the mobile phone side, emissions from GSM transmitters may interfere with the AMPS receiver. Some effort is being made to reduce the guard band while keeping the interference at acceptable levels.
Planning on Future New Systems -- To formulate the future migration plan of the existing AMPS system, a CDMA trial has been proposed to evaluate the performance of the IS-95 system. Other standards, such as IS-136 and DCS-1800, are also under evaluation. In addition, satellite is a very important access technology which is complementary to the terrestrial cellular. Currently, Inmarsat-P, Iridium, and Global Star are some promising systems. TL is evaluating the possibilities of future joint operations.

IN for PCS

To provide a ubiquitous PCS, it is essential to integrate different telecommunication networks and systems. Some of the possible integrated networks and systems are the public switched telephone network (PSTN), digital cordless, mobile systems (especially macro- and microcellular phones), and paging systems. It has been widely accepted that network intelligence integrated by IN is the most efficient, and indeed the only, way to integrate. With IN as the core network, ubiquitous PCS can be provided through the provision of service flexibility, terminal mobility, and personal mobility. Also, the subscriber can use a unique universal personal telecommunication number (UPTN) and a multifunction terminal device to access every type of communication network and service instead of being restricted to just one type, as in today's network environment.
There are definitions of service features to support PCS in IN CS1 by the International Telecommunications Union -- Telecommunications Standardization Sector (ITU-T) [7]. For example, the service features of customer profile management allow the real-time retrieval and updating of subscriber databases. As suggested by ITU-T, the databases in IN are categorized into service control point (SCP) and location register (LR). SCP provides service logic to manage real-time call handling and services, and the LR includes a home location register (HLR) and visitor location register (VLR). These registers store the subscribers' identities and location information essential for providing terminal and personal mobility. With the structure, subscribers can query the LR databases by using Mobile Application Part (MAP) [8] protocols through CCS7. It is believed that the ITU-T will draft the Intelligent Network Application Part (INAP) [9], the MAP, and the Mobile Services Application Part (MSAP) to constitute the complete function of the Personal Communications Application Part (PCAP) [9]. The full network protocols are then composed of PCAP and the underlying layers of protocols, the Transaction Capability Application Part (TCAP) and Network Service Part (NSP), as shown in Fig. 4. TL has continually been devoted to researching CCS7 protocol stack and IN entities for many years, such as SSP (service switching point), SCP , SMS (service management system), and SCE (service creation environment). TL has derived these experiences and technologies to PCS.
Recently, TL launched a PACS trial and development plan to establish an IN/PCS network in the near future [10, 11]. By setting up this IN/PCS network prototype, we expect to acquire the key technologies mentioned previously and to facilitate the PCS realization in Taiwan. A detailed description will be given later.

Wireless Access Technology

Common Air Interface (CAI) specifies the wireless access standard between mobile units and base stations, such as multiple access and duplexing methods. Unlike the network side, wireless access is the most controversial part in the development of PCS standards. To date, there is no worldwide consensus about which kind of technology should be adopted as the international standard for the future. Therefore, in order to explore the feasibility of several proposed wireless access technologies, TL has been involved in the research of wireless access technologies for PCS since 1991. Efforts have been devoted to the study of various wireless multiple access technologies such as TDMA and CDMA. In the CDMA project, we concentrated on the development of new receiver structures and schemes for PN code synchronization, especially for time-variant multipath fading channels [13–16]. In [13] and [14], we proposed a new scheme for PN code tracking which has much better performance than the traditional delay-locked loops, especially for large multipath effects. On the frame synchronization for TDMA systems, we also proposed some efficient algorithms [17] to design the optimum patterns for unique words and evaluated its performance. The performance of various unique words for time-varying multipath fading channels were also given in [17]. Recently, TL also launched a TDMA development project based on Bellcore's Wireless Access Communications System (WACS) [18, 19], now PACS [20]. This project concentrates on the development of handsets, radio ports, radio port control units, and some key technologies of IN for PCS [23, 24]. The architecture of the developing system is shown in Fig. 5. The prototype is expected to be completed in 1996, and the related technologies will be transferred to local industries.
Today, there is still no final international wireless access standard for PCS. In the United States there are seven different air interface standards on the ballot [21]. In Europe, there are several research projects based on different access technologies to achieve the goals of a universal mobile telecommunication system (UMTS) [22]. To keep up with the development of new access technologies in the world, TL will continue to investigate new technologies such as CDMA and others in addition to the TDMA project mentioned above.

Field Trial

In order to keep abreast of innovations in PCS technologies, we have solicited information from potential system providers spanning the main radio manufacturers worldwide. After a thorough survey, we decided to introduce the PACS to DGT as one of its PCS systems. PACS is a low-power microcell system utilizing the existing network infrastructure. It has the potential to achieve the objectives of low cost, high capacity, and high quality. TL plans to conduct a public trial on PACS in mid-1997, together with DGT's three regional operating units. The main purpose of this trial is to verify the feasibility of the system in our environment and gain valuable operation expertise. As shown in Fig. 6, besides the TL trial area, the trial also covers the service areas of the three regional telecommunication administrations, NTTA, CTTA, and STTA. The trial plan is divided into two phases, as shown in Fig. 7. Phase I is tried on commercial purchased products. However, phase II is based on self-developed PACS entities. The PACS switches are also connected to the PSTN for internetworking and have mobile originating/ terminated features. Besides, some supplementary services (e.g., call forwarding, call waiting, and caller identification presentation) are also provided. The numbering plan complies with PLMN and PSTN rules, using "country code + national destination code + subscriber number."

Propagation Measurements and Modeling

Technologies for radio propagation measurement and prediction are necessary for coverage planning, interference reduction, and service quality evaluation of cellular communications systems. For the purpose of developing these crucial technologies, much research on radio propagation and modeling has been done by TL recently. Major topics include measurements and modeling of macrocell, microcell, and indoor radio propagation, and the development of cell design tools for microcell and PCS systems. These research efforts are summarized below.
Macrocell Propagation -- AMPS and GSM systems have been adopted for the mobile communication services in Taiwan. Since the radio propagation characteristics are deeply dependent on the terrain features of streets and buildings in an urban environment, it is necessary to develop accurate propagation models to predict propagation loss. In order to characterize the macrocell radio propagation, we carried out 900 MHz radio propagation measurements in Taipei City. In this research, the well-known ray theory and edge diffraction theory are used to formulate the received signal. From the comparison of measurement data and predicted values, one can see that the signal levels received at line-of-sight or out-of-sight propagation streets can be evaluated well by the two-ray model (direct and ground-reflected waves) or the combination of free-space propagation and edge diffraction, respectively. According to the research results [25] and a building and street database, system engineers can estimate the signal coverage and determine cell layouts and so on.
Microcell Propagation -- Due to the tremendous growth of cellular mobile and the objectives of future personal communications, the microcell and PCS technologies will be introduced and established in Taiwan. The deployment of the microcellular system is used in high-traffic-density areas. Because radio propagation is quite different in microcell environments from the macrocell one, we devoted ourselves to studying the propagation characteristics [26] based on experimental data and theoretical analysis. The measurement was made in a typical rectilinear street environment for transmitting antenna height below the rooftops of surrounding buildings. In this study, the ray theory and uniform GTD (geometric theory of diffraction) method were used to formulate the received signals for line-of-sight and non-line-of-sight propagation streets. From the comparison of theoretical analysis and measurement data, we obtain two major results. First, for line-of-sight propagation, in addition to the direct ray, the rays reflected from walls and the ground have a heavy effect on the received signal strength. In general, more accurate prediction results are obtained if more rays are considered. Second, for non-line-of-sight propagation, both building reflection rays and corner diffraction rays give contributions to the receiving power. However, when the receiver is near or far away from the corner site, building reflection rays and corner diffraction rays play an important role on the received signal.
Indoor Propagation -- Radio local area network (LAN) and PCS systems will have important applications for indoor environments, and their implementation require an understanding of the propagation characteristics of ultra-high-frequency (UHF) radio signals inside such environments. Hence, there is a need to establish propagation prediction models which take into account the variability of architectural configurations, building materials, and so forth. A good prediction model can make planning and installation of these systems as easy and cheap as possible. For indoor radio propagation, two studies based on experiments have been conducted. In the first, we investigated the effects of low partitions inside a modern office on radio wave propagation. Both an empirical and a theoretical model were developed to formulate the propagation losses due to the partitions. In the former [27, 28], the effects due to low partitions, file cabinets, and concrete pillars can be distinguished in detail by use of the method of least square regression. In the latter [28, 29], theories of single and multiple knife-edge diffraction were employed to compute the received signal strength. The second study measured propagation penetration loss due to building floors and room walls, diffraction loss due to the corridor corner, and propagation loss inside a long corridor. From these data, we have estimated the propagation effects [30] due to these typical blockages inside buildings. Based on the measured results, the work on modeling the propagation characteristics for various configurations is being done presently.
Cell Design Tools -- A reliable cell planning tool will play an important role for efficient microcellular or PCS system design. In order to establish the cell layout technology, TL proposed the architecture of tool systems and cooperated with domestic universities to develop the application tools. The entire research includes three parts: propagation measurement, propagation modeling, and software development. Each is individually conducted by one of three universities through the commissioned project.

RF Technology

The current RF researches in TL concentrate on the development of radio subsystems for the subscriber unit (SU) and radio port (RP) for PACS. The development can be separated into two stages: the so-called microwave integrated circuit (MIC)-integrated prototype stage, and the monolithic microwave integrated circuit (MMIC) stage. The first stage is aimed at the design of key circuits and the verification of performance of radio submodule prototypes. PACS chipsets planned to be developed in the second stage will include the GaAs-based MMIC for RF front-end and Si-based RFIC for intermediate frequency (IF) submodules. The following summarizes the research results and development planning on this topic.
Low-Noise Amplifier (LNA) -- LNA performance is crucial to the sensitivity and dynamic range of the receiver. LNA designed for MIC technology is suitable for RP because size is not a stringent factor for RP, and better performance is acquired. The effort to fulfill LNAs in SU will be concentrated on the development of GaAs MMIC technology.
Power Amplifier (PA) -- A major challenge in designing a PA is to maintain the power-added efficiency (PAE) without losing the linearity required for a */4 differential quadrature phase shift keying (DQPSK) modulation scheme. So far, an RP PA module was designed to operate with class F type [31]. The implemented RP PA was measured with a PAE above 50 percent and second harmonic level less than –60 dBc when output power was 29 dBm. Designing an SU PA is a greater challenge because it is not only considered for linearity and power consumption, but also size, cost, and power-on/off switching times. The power-on/off times are stringently controlled to minimize inter-time-slot interference because uplink in PACS is TDMA burst mode. Implementation of the MMIC-based SU PA will be carried out in the second stage.
Synthesizer -- Synthesizer modules were also designed and fabricated in TL. Stability, phase noise, and switching time are the dominant parameters for synthesizer design. The short-term variations over the frame duration (i.e., 2.5 ms) were measured without exceeding 1 ppm. SU synthesizer switching time is an important parameter because the SU is required to make quality measurements in other frequency channels between TDMA bursts [32]. The SU synthesizer switching time was measured without exceeding 0.25ms. Both synthesizers in the RP and SU were tested with SSB phase noise level less than –80 dBc/Hz at an offset of 10 kHz from the carrier.
Antenna -- Microstrip inverted-F and mono-pole antennas were designed and fabricated. The antenna diversity architecture is employed in SU, so microstrip inverted-F is designed for the purpose of concealing itself in the handiest housing. Both the inverted-F and mono-pole antennas were measured with bandwidth of 100 MHz, VSWR < 1.8, and antenna gain of about 4 dB.
Mixer -- Mixer development will concentrate on the MMIC stage. Image rejection FET mixers will be designed to increase the image rejection capability and reduce the filter loading for image rejection and then facilitate the implementation of an on-chip image rejection filter.
In General -- The development of an SU radio subsystem is far more challenging than that of an RP. Handsets are requested to achieve the requirements of low cost, low power consumption, small size, and thus high degree of integration. Therefore, two main technologies will be further developed in TL to meet above requirements. They include the establishment of accurate RF large-signal and noise models for MESFET, and electromagnetic field analysis for the electromagnetic interference (EMI) problem when many circuits are integrated at a very compact level.

Collaboration with Local Academic Organizations

During the past few years, TL has been supporting local universities in conducting PCS-related research works. For example, we have supported several research projects on CDMA technologies ranging from code tracking to code acquisition to power control algorithms to handoff algorithms. Some results on the analysis and design of code tracking and code acquisition schemes were published in [33, 34]. For the power control and handoff algorithms, the study focused on the North American mobile CDMA standard IS-95. The performance of the power control algorithm of IS-95 on the reverse link is studied via computer simulation. A more practical power control mechanism is proposed. To analyze the soft handoff unique to a CDMA cellular system, a tractable model based on the Markov chain is proposed which facilitates the analysis of system performance. Regarding TDMA technologies, one research project studies the effect of frame patterns on the data throughput of an integrated TDMA mobile system providing voice and data services. This study is developing a reliable and effective method for determining the optimal relative positions of voice and data slots within a TDMA frame [35]. Another study investigated the slot allocation issue in the design of a TDMA mobile radio system integrating circuit-switched voice traffic and packet-switched data traffic buffer capacity. For determining the optimal slot allocation, this study proposes a heuristic criterion for assessing the performance of an integrated TDMA system [36].

Conclusions

Personal communications services is one of the most important development projects for telecommunications in Taiwan, Republic of China. Since 1992, this project has been undertaken by the Directorate General of Telecommunications, the only services provider for public telecommunications in Taiwan. An evolution plan based on the development of IN and integration of the existing wireline and wireless systems has been adopted by DGT for developing PCS. With implementation of this plan, DGT shall be able to provide truly ubiquitous PCS in Taiwan in the coming decade.
In this article, the PCS development plan in DGT was described first. Then the PCS R&D activities at Telecommunications Laboratories, a research institute of DGT, were described in more detail. Such activities include the enhancement of existing cellular systems, IN technology for PCS, wireless access technology, field trials, propagation measurements and modeling, and RF technology.

Acknowledgment

Since July 1, 1996, the operational and regulatory roles of Directorate General of Telecommunications (DGT) have been separated. The government-owned Chunghwa Telecom Co., Ltd. was established to sustain the operational business of the former DGT. It is noted that the study mentioned in this article was conducted before July 1, 1996, and the terminology used was still based on the position of the former DGT.
Some of the work was done during the first author's study at National Central University. The support of Professor C. D. Chung is appreciated.

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Biographies
 Mu-Piao Shih received a B.S. degree in electronic engineering and an M.S. degree in electrical engineering from National Taiwan Ocean University and National Taiwan University in 1975 and 1983, respectively. Currently he is pursuing his Ph.D. degree in electrical engineering at National Central University. Since 1979, he has been with Telecommunication Laboratories, DGT, MOTC, and took the position of chief research engineer in 1993. After the reshuffle of DGT on July 1, 1996, he was appointed general project manager of personal communications services at Telecommunication Laboratories, Chunghwa Telecom Co., Ltd. His major interests are in the areas of wireless communications, satellite communications, and microwave circuits design.
Lir-Fang Sun received a B. S. and an M. S. degrees in computer science from Tamkiang University and National Chiao Tung University in 1975 and 1981, respectively, and a Ph.D. degree in electrical engineering from National Taiwan University in 1988. From December 1977 to June 1982, she was with Switching Systems Laboratory, Telecommunication Laboratories/MOTC for implementation of the PABX prototype and PEX-250 commercial product. From 1982 to 1984, she was a senior software designer in the C400 auto-dial project. From 1984 to 1989, she was the project leader of a new telephone services project in the Network Planning Laboratory, TL/MOTC. From 1989 to 1991 she visited AT&T Bell Laboratories in Chicago as technical staff for interworking of SS7 with 5ESS. Since 1991, she has been in charge of the IN project in the Networking Planning Laboratory, TL/MOTC. She was assigned director of the Labor safety and Health Dept., TL/MOTC in November 1992. She is currently a managing director of the Planning and Technology Promotion Department of Telecommunication Laboratories.
Shyue-Ching Lu graduated from the University of Hawaii with a Ph.D. in electrical engineering in 1976. After graduation, he Joined the Telecommunication Laboratories (TL), the research arm of the Directorate General of Telecommunications (DGT), as a research engineer in the Transmission System Laboratory from 1976 to 1977. Under an exchange program, Dr. Lu worked at COMSAT Labs as a research engineer in 1977–1978. Then he acted as project manager and director of the Transmission Systems Lab, 1978–1982. He was subsequently appointed deputy managing director of TL in 1982 and assumed the post of managing director of TL from 1986 to 1993. From 1993 to 1994, he was director-general of the Department of Posts and Telecommunications, Ministry of Transportation and Communications. He took the position of deputy director-general of DGT from July 1994 to June 1996. Currently Dr. Lu is president and chief executive officer of Chunghwa Telecom Co., Ltd. which was established on July 1, 1996 to sustain the operating responsibilities of the former DGT.
Duei Tsai received a B.S. in electronics engineering from National Taiwan Institute of Technology in 1980, and his M.S. and Ph.D. in electrical engineering from National Taiwan University in 1983 and 1987, respectively. He joined the Directorate General of Telecommunications in 1969. Since then, he has been engaged in the telecommunications service industry as assistant engineer, corporate planning director, and chief engineer.