How to compute Channel State Information (CSI) for MIMO OSTBC over 2x1 Flat Rayleigh Fading Channel example

Hi,

I'd like to know how to compute the Channel State Information (CSI) for the MIMO OSTBC over 2x1 Flat Rayleigh Fading Channel, described here:

Concatenated OSTBC with TCM - MIMO Example - Communications System Toolbox

I'd like to modify this example to use actual hardware, a 2x2 MIMO RF front-end. I've got the raw IQ signals being captured over the two RF channels with Simulink and also validated the single channel case with a QPSK example, so the hardware is working.

What I'd like to do now is to replace the MIMO channel block in the example with the actual RF front-end simulink block, and compute the channel state estimates and feed it to the OSTBC Combiner in the receiver block.

Q01: What are the parameters for the channel state information (CSI) in the above model?

Q02: How can I compute the CSI for the above model, if I were to replace the MIMO channel with an actual RF front-end hardware?

Regards,

Elvis Dowson