Engineering topics

Davies, N. George

Publications and source records attributed to Davies, N. George.

3 records

NASA NTRS1993

Implementation of a system to provide mobile satellite services in North America

This paper describes the implementation of the ground network to support Mobile Satellite Services (MSS). The system is designed to take advantage of a powerful new satellite series and provides significant improvements in capacity and throughput over systems in service today. The system is described in terms of the services provided and the system architecture being implemented to deliver those services. The system operation is described including examples of a circuit switched and packet switched call placement. The physical architecture is presented showing the major hardware components and software functionality placement within the hardware.

Johanson, Gary A.↗

NASA NTRS1989

Practical constraints on network architecture and signalling in the MSAT system

Telesat Mobile Inc. plans to provide mobile satellite communications services in Canada in 1993/4, in close cooperation with the American Mobile Satellite Consortium Inc., which will be providing services in the U.S.A. L-band frequencies will be used in multiple beams for communication with mobile terminals. Ku-band frequencies will be used for the feeder-links to fixed stations. The system will support voice and data communications. The baseline Canadian system will support approximately 450 assignable voice channels, some fraction of which will be the equivalent in data channels. The method of multiple access will be Frequency Division Multiple Access/Single Channel Per Carrier. The availability of frequencies, the availability of technology and the time scale for implementation all constrain the network architecture for the system. Further, it is important to have an open specification to encourage multiple equipment vendors. The interplay of these constraints is discussed.

Davies, N. George↗

NASA NTRS1988

Development of the network architecture of the Canadian MSAT system

A description is given of the present concept for the Canadian Mobile Satellite (MSAT) System and the development of the network architecture which will accommodate the planned family of three categories of service: a mobile radio service (MRS), a mobile telephone service (MTS), and a mobile data service (MDS). The MSAT satellite will have cross-strapped L-band and Ku-band transponders to provide communications services between L-band mobile terminals and fixed base stations supporting dispatcher-type MRS, gateway stations supporting MTS interconnections to the public telephone network, data hub stations supporting the MDS, and the network control center. The currently perceived centralized architecture with demand assignment multiple access for the circuit switched MRS, MTS and permanently assigned channels for the packet switched MDS is discussed.

Davies, N. George↗