Impact of spatial correlation on orthogonal precoding for MIMO transmissions in tunnel
Résumé
Multiple-input,Multiple-output (MIMO) techniques
have proven their potentiality for transmissions in the tranport domain even in specific context such as tunnels. When perfect channel state information (CSI) is available at the transmitter,
performance improvement is allowed through a precoding operation. However, the performances of such a closed-loop MIMO system depends on the spatial correlation in the channel, the
quantity and the quality of the CSI. A perfect knowledge of the CSI is rarely available in practice because the CSI usually undergoes various impairments such as channel estimation errors
and quantization errors. To overcome these drawbacks we propose the investigation of two limited feedback precoders that allow to reduce simultaneously processing complexity and the
amount of feedback information. The first one named OSM is based on the orthogonalization of the channel and the second one is the basic Grassmann precoder based on the quantization of the information. The comparison is performed both for an ideal Rayleigh channel and a correlated channel considering the Kronecker model.