Low complexity affine MMSE detector for iterative detection-decoding MIMO OFDM systems

D.N. Liu, M.P. Fitz
2008 IEEE Transactions on Communications  
Iterative turbo processing between detection and decoding shows near-capacity performance on a multiple-antenna system. Combining iterative processing with optimum frontend detection is particularly challenging because the front-end maximum a posteriori (MAP) algorithm has a computational complexity that is exponential. Sub-optimum detector such as the soft interference cancellation linear minimum mean square error (SIC-LMMSE) detector with near front-end MAP performance has been proposed in
more » ... been proposed in the literature. The asymptotic computational complexity of SIC-LMMSE is O(n 2 t nr + ntn 3 r + ntMc2 Mc ) per detection-decoding cycle where nt is number of transmit antenna, nr is number of receive antenna, and Mc is modulation size. A lower complexity detector is the hard interference cancellation LMMSE (HIC-LMMSE) detector. HIC-LMMSE has asymptotic complexity of O(n 2 t nr + ntMc2 Mc ) but suffers extra performance degradation. In this paper, two front-end detection algorithms are introduced that not only achieve asymptotic computational complexity of O(n 2 t nr + ntn 2 r [Γ (β) + 1] + ntMc2 Mc ) where Γ (β) is a function with discrete output {−1, 2, 3, ..., nt} and O(ntMc2 Mc ) respectively. Simulation results demonstrate that the proposed low complexity detection algorithms offer exactly same performance as their full complexity counterpart in an iterative receiver while being computational more efficient. Index Terms-Turbo processing, soft interference cancellation, affine MMSE filtering, low density parity check (LDPC) codes, iterative decoding.
doi:10.1109/tcomm.2008.050623 fatcat:lu3zztwnp5hghguyfvtv5jc5ry