Linear precoders for OFDM wireless communications with MMSE equalization: Facts and results

This contribution aims at analyzing the performance of MMSE equalizers for large linear precoded OFDM transmissions over fading wireless channels with limited diversity and channel state information available only at the receiver. Linear Precoding consists in multiplying by a N × K isometric matrix a K-dimensional vector obtained by serial to parallel conversion of a symbol sequence to be transmitted. Based on the Free Probability Theory, asymptotical analysis (N → +∞, K → ∞ and K/N → α ≤ 1) of the SINR is conducted to understand the different parameters involved in Linear Precoded OFDM schemes. The theoretical results are confirmed by numerical simulations when considering convolutional coding with finite memory.