USRP MU-MIMO setup

[orange_spider]

Hello community, 

I want to observe effect of interference and also interference mitigation in multi user multiple input multiple output (MU-MIMO) scenario.

Setup parameters are 2x2 MIMO and 3 users in the wireless network.

Then, I have four NI-USRP 2922 (for user-1 // connected via MIMO cable) and two NI-USRP 2901 (for user-2 and user-3).

How can I achieve channel track of both users ? 

Regards,

[TylerC1123]

Hi Orange_Spider,
 
Can you clarify what you mean by channel track? Are you looking to track what signals are coming from what user or something different? 
 
Additionally, what does the interference look like to the user receiving the signals?
 
Thanks,

[orange_spider]

Hello Tyler C.,

I naturally mean by channel tracking is channel estimation processing at the receiver node.

Just consider at the figure file at the attachment. There are 3 user pair, I want to implement 2x2 MIMO for each user pair.  Signaling can be handled at the same frequency and at the same time. (We also have NI-CDA 2990 Octoclock for synchronization.) Then we want to align interfering users (for instance x2 and x3 are interferer users considering x1 according to figure.) via precoding matrices (V) and interference suppression matrices (U). Yet, V and U matrices can be constituted in terms of MIMO channel matrix coefficients H11,H12, ... , H33 etc . How can I achieve H11,H12, ... , H33 etc when I use both of devices at the same time and frequency in OFDM waveform ?