A. Scaglione et al., Lagrange/Vandermonde MUI eliminating user codes for quasi-synchronous CDMAin unknown multipath, IEEE SIGNAL, 48(7), 2000, pp. 2057-2073
A family of codes for low-complexing quasi-synchronous code division multip
le access (CDMA) systems Is developed in order to eliminate multiuser inter
ference (MUI) completely in the presence of unknown and even rapidly varyin
g multipath, Judiciously designed precomputable symbol periodic user codes,
which we term Lagrange or Vandermonde, and the corresponding linear receiv
ers offer a generalization of orthogonal frequency division multiplexing (O
FDM), which are especially valuable when deep-fading, carrier frequency err
ors, and Doppler effects are present. The flexibility inherent to the desig
ned transceivers is exploited to derive transmission strategies that cope w
ith major impairments of wireless CDMA channels, The symbol-periodic code d
esign is also generalized to include the class of aperiodic spreading and o
rthogonal multirate codes for variable bit rate users. Performance analysis
and simulations results illustrate the advantages of the proposed scheme o
ver competing alternatives.