Zd. Wang et Gb. Giannakis, Block precoding for MUI/ISI-resilient generalized multicarrier CDMA with multirate capabilities, IEEE COMMUN, 49(11), 2001, pp. 2016-2027
Potential increase in capacity along with the need to provide multimedia se
rvices and cope with multiuser interference (MUI) and intersymbol interfere
nce (ISI) arising due to wireless multipath propagation, motivate well mult
irate wideband code-division multiple-access (CDMA) systems. Unlike most ex
isting continuous-time symbol-periodic and multipath-free studies, the pres
ent paper develops an all-digital block-precoded filter-bank framework capa
ble of encompassing single- or multirate transceivers for asynchronous or q
uasi-synchronous CDMA transmissions through multipath channels. Thanks to s
ymbol blocking and through appropriate design of user codes, the resulting
generalized multicarrier (GMC) CDMA system not only subsumes known multicar
rier CDMA variants, but also equips them with flexible multirate capabiliti
es. It is computationally simple, and guarantees symbol recovery regardless
of the (possibly unknown) FIR multipath channels in both downlink and upli
nk setups. Simulations corroborate that the novel GMC-CDMA system outperfor
ms existing multirate alternatives in the presence of asynchronism and mult
ipath, and illustrate the feasibility of recovering blindly multirate trans
missions received through unknown frequency-selective channels in the uplin
k. Performance of GMC-CDMA system in UNITS channels is also simulated and c
ompared with existing multirate schemes.