Block Spreading for MUI/ISI-Resilient Generalized Multi-Carrier CDMA with Multirate Capabilities

Potential increase in capacity along with the need to provide multimedia services and cope with multiuser interference (MUI) and intersymbol interference (ISI) arising due to wireless multipath propagation, motivate well multirate wideband codedivision multiple-access (CDMA) systems. This paper develops an all-digital block-spread filterbank framework capable of encompassing singleor multi-rate transceivers for asynchronous or quasi-synchronous CDMA transmissions through multipath channels. Thanks to symbol blocking and through appropriate design of user codes, the resulting generalized multi-carrier (GMC) CDMA system guarantees symbol recovery irrespective of the (possibly unknown) FIR multipath channels in both downlink and uplink setups with low complexity FIR receivers. Simulations corroborate that the novel GMC-CDMA system outperforms existing multirate alternatives in the presence of asynchronism and multipath.