Title :
Coded direct sequence spread spectrum systems over satellite channels using an adaptive receiver
Author :
Oppermann, Ian ; Vucetic, Branka S.
Author_Institution :
Dept. of Electr. Eng., Sydney Univ., NSW, Australia
Abstract :
This paper examines the performance of a direct sequence spread spectrum multiple access (DS-SSMA) system used over two typical, frequency-selective, fading channels for intermediate circular orbit (ICO) satellites. In an attempt to increase the system efficiency, a timing and phase synchronisation insensitive, adaptive receiver described by Rapajic and Vucetic (1994) has been implemented. The receiver is a least-mean-squares (LMS) implementation of a minimum mean square error (MMSE) receiver. This system has been combined with soft-decision convolutional coding in order to improve the system performance under the fading conditions relative to the uncoded system and to allow as many simultaneous users as possible. Various code rates have been examined and the results are given. This paper specifically focuses on DS-SSMA systems with low spreading ratios. The satellite channels used in this paper were produced by models developed as a result of experimental measurements
Keywords :
Rician channels; Viterbi decoding; adaptive filters; code division multiple access; convolutional codes; fading; interference suppression; least mean squares methods; pseudonoise codes; radio receivers; satellite communication; spread spectrum communication; CDMA; DS-SSMA system; ICO satellites; LMS implementation; MMSE receiver; adaptive receiver; code rates; direct sequence spread spectrum multiple access; frequency-selective fading channels; intermediate circular orbit satellites; least-mean-squares implementation; low spreading ratio; minimum mean square error receiver; satellite channels; simultaneous users; soft-decision convolutional coding; Convolutional codes; Extraterrestrial measurements; Fading; Frequency synchronization; Least squares approximation; Mean square error methods; Satellites; Spread spectrum communication; System performance; Timing;
Conference_Titel :
Spread Spectrum Techniques and Applications Proceedings, 1996., IEEE 4th International Symposium on
Conference_Location :
Mainz
Print_ISBN :
0-7803-3567-8
DOI :
10.1109/ISSSTA.1996.563442
