Accession Number : ADA307158

Title :   A Comparison Study of CDMA Versus TDMA/FDMA Leo Satellite Systems.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Ciocco, Timothy M.

PDF Url : ADA307158

Report Date : MAR 1996

Pagination or Media Count : 66

Abstract : In this thesis, two LEO satellite systems with different multiple access schemes are analyzed. The first system, GLOBALSTAR, uses CDMA. Equations are developed to calculate the maximum capacity of one satellite, of one satellite's user beam, and of the entire GLOBALSTAR system over CONUS. A detailed description of GLOBALSTAR's outage probability, the probability that a call will be dropped from the system or blocked from connection with the system, is given and graphed against varying average call time and varying call arrival rate. The second system, IRIDIUM, uses TDMA/FDMA. Equations are similarly developed to calculate the maximum capacity of one satellite, of one satellite's user beam, and of the entire IRIDIUM system over CONUS. The probability of success or failure of an IRIDIUM subscriber obtaining a system channel is given by the Erlang Loss Formula and graphed against varying average call time and varying call arrival rate. Results show GLOBALSTAR provides five times the service capacity of IRIDIUM over CONUS and provides a better probability of obtaining a system channel for a call than will IRIDIUM.

Descriptors :   *COMMUNICATIONS TRAFFIC, *COMMUNICATION SATELLITES, *MULTIPLE ACCESS, CAPACITY(QUANTITY), COMPARISON, THESES, USER NEEDS, RADIO LINKS, CHANNELS, FREQUENCY DIVISION MULTIPLE ACCESS.

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE