We consider a DS-CDMA system employing aperiodic spreading sequences (APS) as signature sequences for different users. Multiple transmission antennas (MA) are employed for increasing the network capacity. It is assumed that partial or total knowledge of the downlink channel is available at the base-station due to either a time-division duplex (TDD) or some feedback structure in the network. Spatial and temporal dimensions can no longer be jointly exploited due to the aperiodic spreading. Hence, spatio-temporal pre-cancellation of downlink interference (zero-forcing) is no longer possible. However, beamforming can be applied to maximize the signal-to- noise plus interference (SINR) ratio on a user-to-user basis. We proceed with such an approach and provide closed-form relations for the signal and interference terms at the output of a mobile station RAKE receiver. We also show that using the spatial dimension at the base station enhances the system performance. The mobile receiver can later employ an equalizer to do away with the residual intersymbol interference, thus maximizing the matched filter bound (MFB) at its output.
Spatio-temporal array processing for aperiodic CDMA downlink transmission
Asilomar 1999, 33rd IEEE Annual Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, USA
Type:
Conference
City:
Pacific Grove
Date:
1999-10-27
Department:
Communication systems
Eurecom Ref:
297
Copyright:
© 1999 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
See also:
PERMALINK : https://www.eurecom.fr/publication/297
