Title :
Long-term Krylov-prefilter for reduced-dimension receive processing in DS-CDMA systems
Author :
Dietl, Guido ; Joham, Michael ; Utschik, W. ; Nossek, Josef A.
Author_Institution :
Inst. for Circuit Theor. & Signal Process., Munich Univ. of Technol., Germany
Abstract :
Currently, long-term channel properties are only used for reduced-dimension processing in eigen subspaces. We introduce a preRAKE at the transmitter in the uplink of a direct sequence (DS) CDMA system with non-orthogonal codes in order to exploit long-term channel properties for reduced-dimension Wiener filtering in Krylov subspaces at the receiver. Simulation results show that Krylov outperforms eigen prefiltering with and without previous correlation. Moreover, the long-term is better than or equal to short-term processing except for optimal filtering in Krylov subspaces assuming multipath environments.
Keywords :
Rayleigh channels; Wiener filters; code division multiple access; filtering theory; multiuser channels; radio links; radio receivers; spread spectrum communication; DS-CDMA systems; Krylov subspaces; direct sequence CDMA system; dispersive channels; eigen prefiltering; eigen subspaces; flat Rayleigh fading channels; long-term Krylov-prefilter; long-term channel properties; multipath environments; nonorthogonal codes; optimal filtering; receiver; reduced-dimension receive processing; simulation results; uplink; Computational complexity; Delay; Dispersion; Filtering; Matched filters; Multiaccess communication; Multiple access interference; Signal processing; Transmitters; Wiener filter;
Conference_Titel :
Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th
Print_ISBN :
0-7803-7467-3
DOI :
10.1109/VETECF.2002.1040392