Hi User,
The throughput by definition is the maximum data rate transmitted by the communication system. In the theoretical limit it is equal to the Shanon channel capacity C. The spectral efficiency eta spectral is the ratio of the transmitted data rate rb divided by the channel bandwidth B, that is erta spectral= rb/B bits/Hz.
According to to Shanon, there is a relation between the spectral efficiency, eta spectral, and the signal to noise N + interference I provided that the interference signal is like to noise such that:
eta spectral= log2(1 + S/ (N+I)), where S is the received signal, N is the noise and I is the interference power. So, in order to increase eta for a given channel one has to increase its SINR.
This is for single input single output channel SISO.
For multiple input multiple output wireless channel with Nt transmit antenna and Nr receive antenna, one can recuse the bandwidth B of the channel many times such that the bandwidth multiplicity can reach up to min (Nt and Nr). Then if Nt=Nr, then the bandwidth will be multiplied by Nt. For the same signal to noise ratio, one can increase the data rate by Nt. So, the same channel for SISO with data rate of rb can transmit data rate up to Nt rb for NtxNt MIMO system. The multiplicity of the bandwidth can be achieved only if Nt independent paths exist in the space between the transmit and receive antenna arrays. This is called space division multiplexing.
You can substitute the the band width, the number of antennas , The signal power at the receiver, the interference power at the receiver and the noise power at the input of the receiver in the above Shanon formula to get the required channel capacity.
