Title :
Embedded Iterative Semi-Blind Channel Estimation for Three-Stage-Concatenated MIMO-Aided QAM Turbo Transceivers
Author :
Peichang Zhang ; Sheng Chen ; Hanzo, Lajos
Author_Institution :
Sch. of Electron. & Comput. Sci., Univ. of Southampton, Southampton, UK
Abstract :
The lack of accurate and efficient channel estimation (CE) for multiple-input-multiple-output (MIMO) channel state information (CSI) has long been the stumbling block of near-MIMO-capacity operation. We propose a semi-blind joint CE and three-stage iterative detection/decoding scheme for near-capacity MIMO systems. The main novelty is that our decision-directed (DD) CE exploits the a posteriori information produced by the MIMO soft demapper within the inner turbo loop to select a “just sufficient number” of high-quality detected soft bit blocks or symbols for DDCE, which significantly improves the accuracy and efficiency of DDCE. Moreover, our DDCE is naturally embedded into the iterative three-stage detection/decoding process, without imposing an additional external iterative loop between the DDCE and the three-stage turbo detector/decoder. Hence, the computational complexity of our joint CE and three-stage turbo detector/decoder remains similar to that of the three-stage turbo detection/decoding scheme associated with the perfect CSI. Most significantly, the mean square error (MSE) of our DD channel estimator approaches the Cramér-Rao lower bound (CRLB) associated with the optimal-training-based CE, whereas the bit error rate (BER) of our semi-blind scheme is capable of achieving the optimal maximum-likelihood (ML) performance bound associated with the perfect CSI.
Keywords :
MIMO communication; computational complexity; decoding; error statistics; iterative methods; maximum likelihood estimation; mean square error methods; radio transceivers; Cramer-Rao lower bound; DD channel estimator; MIMO-capacity operation; bit error rate; channel state information; computational complexity; decoding scheme; embedded iterative semi-blind channel estimation; high-quality detected soft bit blocks; mean square error; three-stage iterative detection; three-stage turbo detector/decoder; three-stage-concatenated MIMO-aided QAM turbo transceivers; Channel estimation; Decoding; Detectors; Iterative decoding; Joints; MIMO; Vectors; Cramér–Rao lower bound (CRLB); joint channel estimation and three-stage turbo detection/decoding; multiple-input–multiple-output (MIMO) systems; near-capacity;
Journal_Title :
Vehicular Technology, IEEE Transactions on
DOI :
10.1109/TVT.2013.2271872