Site:                KDD Research and Development Laboratories
                      2-1-15 Ohara Kamifukuoka-Shi Saitama
                      356-8502
                      Japan

Date Visited:  31 May 1999

WTEC Attendees: W. Stark (report author), N. Moayeri

Hosts:           Dr. Takuro Muratani, President and CEO
                    Dr Masayoshi Ohashi
                    Takeshi Mizuike
                    Hiroyasu Ishikawa
                    Kenichi Minamisono
                    Yoshio Takeuchi
                    Satoshi Miyaji

BACKGROUND

KDD Research and Development Laboratories (KDD R&D) is the main research part of KDD. KDD R&D employs about 150 researchers on a variety of topics ranging from mobile wireless communications to underwater fiber optical communications. The laboratory is organized into 17 different laboratories and research units. The laboratories conduct research on multimedia, Internet, radio and mobile communications, lightwave communications, network design and management, and other areas. Fundamental research is particularly active concerning devices for optical communication systems.

DISCUSSION AND RESEARCH PROJECTS

The meeting began with welcomes and introductions. Dr. Takuro Muratani explained the focus of the laboratories. The WTEC panel members gave a presentation focusing on the purpose of the visit. Then, KDD R&D personnel gave several talks. Hiroyasu Ishikawa presented research on carrier frequency offset-spread spectrum method for wireless LAN system using 2.4 GHz ISM band. Yoshio Takeuchi presented information on field trials for IMT-2000. The panelists saw a demonstration of a very low bit rate video codec transmitting information of a wireless link (albeit stationary) given by Satoshi Miyaji. Finally, Takeshi Mizuike gave a presentation on computer software development for radio communication systems.

Carrier Frequency Offset-Spread-Spectrum Wireless LAN

This project uses the 2.4 GHz ISM band to transmit 10 Mbps for a wireless LAN system. The method of operation is essentially a multicarrier operation with 5 different carriers each spread by a factor of 11 and uses a bandwidth of 26 MHz. The current system is point-to-point, using directional antennas. The next generation system will be point-to-multipoint and have data rates up to 18 Mbps. In 2000, an LSI was expected to replace the baseband processing portion of the CFO-SS wireless system.

Field Trials for IMT-2000

The purpose of this project was to verify the performance of wideband CDMA, collect design and operational parameters, and verify new services and applications. The implementation included an interference canceller that has linear complexity in the number of interfering signals and had performance close to that of a decorrelating detector. In addition soft handoff performance and control was verified. The system was a DS-CDMA/FDD system with 4.096 Mcps (million chips per second) using 5 MHz of bandwidth with convolutional and Reed-Solomon codes. The interference canceller was a multi-stage canceller. The wideband CDMA data rate was 8 kbps for voice, 64.128 kbps for circuit switched data, and up to 384 kbps for packet transmission.

Low Bit Rate Video Codec

A demonstration of a low-bit-rate video codec was given to the visiting panel. The codec uses a technique called advanced precoding to provide optimum bit allocation to regions of the video containing significant information when a pre-analysis of each picture frame is completed. The low rate coding makes video transmission possible at rates down to 15 kbps, albeit with some compromise in video reproduction, especially for moving images.

Design Tool for Cellular and Microcellular Networks

KDD R&D has developed software tools for cellular and microcellular planning. The tool CSPLAN does cell site planning and coverage evaluation for microcellular mobile systems using low antenna height. The features include integration of 2-D building shapes into a geometric computation technique for path loss calculation. The tool BSPLAN does propagation prediction and coverage evaluation for mobile base station planning. The features include integrating practical pathloss models with geographic and building databases utilizing building height information average over a 250 m square mesh.

SUMMARY

KDD R&D Laboratories presented products developed during short term R&D projects. These products are derived from basic research activities and include wireless LAN systems for point-to-point operation, low rate video compression for sending video over a wireless link, and base station location planning software tools. Long-term basic research has been conducted, for example, in the area of devices for optical communications but was not part of the discussion. KDD R&D indicated that basic research requirements include propagation modeling and large scale mathematical optimization for base station location planning.


Published: July 2000; WTEC Hyper-Librarian