Precoder design for ISI channels based on iterative LMMSE equalization
Xiaojun Yuan, Haitao Li, Li Ping, Xiaokang Lin · 2008
A precoding technique is proposed for single-carrier block transmission with cyclic prefix (CP) insertion over inter-symbol interference (ISI) channels. The precoder is based on circular convolution that can be implemented in the frequency domain, so that the detection complexity is kept low using the linear-minimum-mean-square-error (LMMSE) frequency domain equalization (FDE) technique. The precoder can be designed in a low-cost way using the water-filling principle, or optimized based on the signal-to-noise-ratio- (SNR-) variance evolution. Numerical results show that the precoding gain roughly corresponds with the water-filling gain.