Title :
Soft-Output MIMO Detectors with Channel Estimation Error
Author :
Jalloul, Louay M. A. ; Alex, Sam P. ; Mansour, Mohamed M.
Author_Institution :
Broadcom Corp., Sunnyvale, CA, USA
Abstract :
New expressions for the soft decision bit log-likelihood ratio (LLR) of a MIMO system using quadrature amplitude modulation (QAM) taking into account channel estimation error (CEE). The bit LLR for the maximum likelihood (ML) and the linear minimum mean-squared error (MMSE) receivers are derived, showing in both receivers explicit scaling of the LLR that is a function of the QAM symbol and the CEE variance. These new expressions for the LLRs are used to show that only modest improvements in the link performance are achieved relative to the LLRs that do not take into account the CEE. This indicates that separating the detector design from channel estimation does not significantly impact the system performance, which leads to simplifications in the overall receiver implementation.
Keywords :
MIMO communication; channel estimation; least mean squares methods; maximum likelihood detection; quadrature amplitude modulation; receivers; MMSE receivers; QAM; channel estimation error; linear minimum mean squared error; maximum likelihood; quadrature amplitude modulation; soft decision bit log likelihood ratio; soft output MIMO detectors; Channel estimation; Detectors; MIMO; Measurement; Quadrature amplitude modulation; Receivers; Vectors; Channel estimation error; MIMO; MMSE; QAM; log-likelihood ratio; maximum likelihood;
Journal_Title :
Signal Processing Letters, IEEE
DOI :
10.1109/LSP.2014.2374425