Site: KDD R&D Laboratories
2-1-5 Ohara Kamifukuoka
Saitama 356
Japan

Date Visited: October 23, 1992

Report Author: B. Edelson

ATTENDEES

NASA/NSF:

W. Brandon
B. Edelson
P. Hager
R. Kwan
C. Mahle
E. Miller
J. Pelton

HOSTS:

Dr. Kinji Ono

Dr. Y. Ito

Dr. Y. Takahashi

Mr. K. Koga

Dr. T. Mizuno

Dr. H. Murakami

Mr. Y. Kamiya

Mr. H. Shinonaga

Mr. T. Mizuiki

Mr. H. Tsubakiyama

BACKGROUND

The Kokusai Denshin Denwa Company, Ltd. (KDD) is the Japanese overseas telecommunications entity. It started in 1953 as a government agency with a service monopoly, but was transformed into a commercial organization. Although KDD has been subject to competition over the last three years, it is still the dominant Japanese international carrier with 1992 revenues of over $2 billion.

KDD R&D Laboratories opened in 1970 and moved into the Kamifukuoka facility in 1987. The transmission technology research program previously located at the Meguro facility in Tokyo was recently transferred there to consolidate all research activities in KDD R&D Labs. KDD Labs employs 175 people, of whom 140 are scientists and engineers (an extremely high ratio). KDD's annual budget for all development is about $83 million, 4% of revenue, of which KDD Labs spends about $35 million. The Labs organization is shown in Figure KDD.1.

Figure KDD.1. Organization of KDD Labs

KDD is heavily invested in undersea cables and is a partner in the construction of the TPC-4 fiber optic cable to connect Japan to North America with 15,000 digital circuits. It is participating in the planning for TPC-5, which will carry 60,000 circuits, connecting Japan, Guam and Hawaii to the North American continent, and for an extensive fiber optic network connecting South East Asia with the Middle East and Western Europe.

KDD also plays an active and significant role in satellite communications. It is a charter member of both INTELSAT and Inmarsat, currently holding investment shares of 4.5% and 9.1%, respectively. It has been technologically influential in both organizations, providing strong leadership in introducing digital transmission techniques.

In 1989 KDD introduced the world's first ISDN service and is now interconnected with 13 countries, providing 64 kbits/sec switched service applicable to voice, G4 facsimile, and video conferencing services. KDD is working hard to extend and upgrade its ISDN network and to provide a broader range of ISDN-compatible services. A good example is KDD's introduction of the "F-Port" store-and-forward facsimile system, an efficient, low cost, value-added service. KDD's willingness to introduce this innovative service in the face of opposition by most international carriers is evidence of its determination to use high technology to increase transmission efficiency, lower user costs, increase traffic, and build market share. Most carriers see only the immediate loss of revenue from cost cutting.

RESEARCH AND DEVELOPMENT ACTIVITIES

The principal development thrust of KDD Labs is directed towards new ISDN services. They also conduct basic research and technology development. Since KDD is restricted from providing domestic service and does not own satellites, KDD Labs concentrates R&D efforts on developing new services and improved transmission techniques for the international market.

KDD sponsors work in satellite communications for its own use (e.g., TDMA), for INTELSAT and Inmarsat, and for its consulting business (mostly with developing nations). The Labs is seen as an important element in developing future satellite communications business for KDD as it has in the past. Figure KDD.2 contains a list of major contributions of KDD R&D Labs to satellite communications over the last thirty years.

Less than one-quarter of the staff, some 30 researchers, is now devoted to satellite communications. Several years ago it was about half the staff. This shift in emphasis reflects the perceived increasing importance of fiber optic cables in international communications.

Figure KDD.2. Major Contributions of KDD R&D Labs to Satellite Communications

KDD R&D Labs has a number of important satellite communications system studies and developments underway:

• "Downsizing" of terminals for mobile satellite communications
• Studies for Inmarsat Project 21, considering both LEO and GEO systems.
• SS-FDMA for INTELSAT
• 120 and 140 Mbits/sec transmission systems for INTELSAT
• VSAT systems

Although KDD R&D Labs is developing B-ISDN at data rates higher than 150 Mbits/sec for fiber optic cables, it has no activity in developing satellite-based B-ISDN. The view of Labs management appears to be that although there is a well recognized need for international B-ISDN services, satellites have no advantage in providing them; whereas, for supercomputer networking (considered a domestic service and thus not a KDD service), while there is no recognized need, satellites have obvious advantages in providing the service.

KDD has under development a wide variety of satellite system techniques and equipment. Several of special note are:

• DISCO -- a satellite communications simulation program for evaluation of a digital satellite link operating in either TDMA or FDMA mode. The program includes consideration of non-linear amplification, interference and noise. It may include several channels and performs end-to-end measurements of link quality in terms of time waveform, power spectrum and BER.
• Fax broadcast system -- provides point-to-multipoint facsimile transmission with conditional access control. The system provides for digital encoding and addressing to individual or groups of users. The system is designed for use in the Inmarsat system, but appears equally applicable and valuable to mobile, broadcast or VSAT system.
• Multi-channel TV coding system -- known as the "MUCCS45," the system accepts up to four high quality video channels, then compresses and multiplexes them into one 45 Mbits/sec (DS3) digital carrier. It uses an efficient proprietary encoding technique operating on the composite video signal. The system has been packaged into compact equipment, now commercially available.
• SAW filters -- microwave surface acoustic wave (SAW) bandpass filters are useful for spacecraft applications because of their linearity and sharp frequency selectivity, combined with both small size and mass. SAW filters have been fabricated for operation in the 1.5 GHz band using quartz substrates. These filters have shown good electrical response in transmission tests. Temperature and aging effects are being evaluated.
• Spacecraft antennas -- following a program of twenty-years duration, a number of advanced high performance antennas suitable for spacecraft use are under development. Recent developments include a shaped offset-fed Gregorian antenna which eliminates sidelobe degradation and depolarization effects due to aperture blockage and also provides optimized beam control from shaping of the reflector -- applicable to VSAT systems; a fan-beam antenna using a double curved approach developed using CAD -- applicable to radio distribution; and a multibeam antenna for optimized coverage of widespread areas.

SUMMARY

KDD R&D Labs is an outstanding research center which continues KDD's long record of accomplishments in the development of terrestrial and satellite communications systems. The Labs has a strong program in satellite communications systems and technology development. In several areas, notably digital transmission systems and earth station technology, KDD R&D Labs is a world leader.

Concentrating on international service, KDD R&D Labs has greatly helped to sustain KDD's technological leadership in both INTELSAT and Inmarsat. KDD's promotion of ISDN will likely be the determining factor as to what role satellites, and therefore INTELSAT, will play in international ISDN. As for Inmarsat, the course of Project 21 will most likely be determined by the results of studies and developments made by KDD.

KDD's neglect of satellite-based B-ISDN is probably due to the small geographic size and dense population of Japan, which can be well served by fiber optic links. KDD did show interest in high data rate (HDR) satellite communications for supercomputer networking and other advanced applications.