Authors:
João Carlos Silva
1
;
Nuno Souto
1
;
Francisco Cercas
1
;
António Rodrigues
1
;
Rui Dinis
2
and
Sérgio Jesus
2
Affiliations:
1
Instituto Superior Técnico/IT, Portugal
;
2
CAPS, Portugal
Keyword(s):
MMSE Equalizer, Gauss, Cholesky, MIMO, W-CDMA.
Related
Ontology
Subjects/Areas/Topics:
Channel Coding, Modulation and Multi-User Detection
;
Detection, Decoding and Diversity Techniques
;
MIMO Systems and Techniques
;
Telecommunications
;
Wireless and Mobile Technologies
;
Wireless Information Networks and Systems
Abstract:
The LMMSE (Linear Minimum Mean Square Error) algorithm is one of the best linear receivers for DS-CDMA (Direct Sequence-Code Division Multiple Access). However, for the case of MIMO/BLAST (Multiple Input, Multiple Output / Bell Laboratories Layered Space Time), the perceived complexity of the LMMSE receiver is taken as too big, and thus other types of receivers are employed, yielding worse results. In this paper, we investigate the complexity of the solution to the LMMSE and the Zero-Forcing (LMMSE without noise estimation) receiver’s equations. It will be shown that the equation can be solved with optimized Gauss or Cholesky algorithms. Some of those solutions are very computationally efficient and thus, allow for the usage of the LMMSE in fully-loaded MIMO systems.