EbNO for MIMO systems

[white4]

Good evening.

I am simulating a MIMO channel, but I have a doubt about adding noise. I am measuring the BER vs EbNo, but Matlab function AWGN requests SNR. I already know that SNR = EbNo + 10log(spectral efficiency), but I don't know what spectral efficiency is while transmiting 4x4 mode with QPSK modulation in each channel. The whole system efficiency is 8bits/s/Hz, but while transmiting, they are "independent" channels whose efficiency is 2bits/s/Hz.

What spectral efficiency should I use?

Thank you.

 

[xlarryzhu]

similar question.
I suppose by using QPSK, a 2bit signal is converted into one QPSK symbol.
does that mean the spectral efficiency?