Title :
Lattice-based subspace decomposition for DS-CDMA detection
Author :
Woodward, Graeme ; Honig, Michael L. ; Vucetic, Branka S.
Author_Institution :
Dept. of Electr. Eng., Sydney Univ., NSW, Australia
Abstract :
Lattice filtering is applied to the MMSE (minimum mean squared error) DS-CDMA receiver. The lattice performs Cholesky decomposition on the sampled input covariance matrix. This identifies information about signal and noise subspaces, which can be exploited to decrease the complexity of the MMSE receiver using LS (least squares) adaptive algorithms. Two reduced complexity techniques are considered: (1) filter truncation and (2) linear combining of multiple truncated subfilters. In both cases, the dimension of the (sub)filters must be larger than that of the user subspace. Numerical results presented compare the performance of these techniques using LMS and LS algorithms
Keywords :
code division multiple access; computational complexity; covariance matrices; lattice filters; least mean squares methods; receivers; signal detection; spread spectrum communication; Cholesky decomposition; DS-CDMA detection; MMSE DS-CDMA receiver; complexity; dimension; filter truncation; lattice filtering; lattice-based subspace decomposition; least squares adaptive algorithms; linear combining; minimum mean squared error; multiple truncated subfilters; sampled input covariance matrix; Adaptive algorithm; Lattices; Least squares approximation; Least squares methods; Matched filters; Multiaccess communication; Multiple access interference; Nonlinear filters; Resonance light scattering; Signal processing;
Conference_Titel :
Spread Spectrum Techniques and Applications, 1998. Proceedings., 1998 IEEE 5th International Symposium on
Conference_Location :
Sun City
Print_ISBN :
0-7803-4281-X
DOI :
10.1109/ISSSTA.1998.726219
