Joint signal precoding in the downlink of spread-spectrum systems

A.N. Barreto, G. Fettweis
2003 IEEE Transactions on Wireless Communications  
The downlink capacity tends to be the limiting factor in future communications systems. In this paper, we propose two schemes for the downlink of code-division multiple-access systems that help reduce the multiuser interference by jointly precoding the transmitted signal based on knowledge of the downlink channel. Methods that operate on blocks of bits will be first developed and a bitwise simplification of these for systems with large processing gains will be derived. The use of multiple
more » ... it antennas will also be considered. These methods provide a substantial capacity increase without requiring complex multiuser detectors at the mobile terminals, and can be applied for instance to time-division duplex systems, which have reciprocal channels. Index Terms-Joint transmission, multiuser spread spectrum, precoding, pre-Rake, time-division duplex code-division multiple access (TDD-CDMA), transmission diversity.
doi:10.1109/twc.2003.811179 fatcat:eiees3vrsngkbb4eo33e6jr5lm