Last Post: July 8, 2016:
So I am trying to clear up something on MIMO and Spatial Streams.
MIMO is Multiple Tx and Rx antennas (multiple radio chains) different data out each Tx antenna. So if I have 3x3 that means 3 Tx and 3 Rx. Now with MIMO all 3 Tx antennas will transfer data but it will be the same data.
Spatial Streams data basically gets divided into multiple streams and sent out the antenna. So if the config is 3x3:2 there will be 2 streams going out of the two antennas (third antenna will just send out redundant data) and if the config is 3x3x3, there will be 3 Tx antennas sending out 3 streams of different data?
Basically each stream out of each antenna will have different data which in return improves throughput.
One has to be careful when using the word "different" when MIMO is the topic.
You can rightfully argue that the bits coming over each stream are different, but this is only a result of the data being "multiplexed" over multiple streams. You could also argue they are all part of the "same" data, just different parts.
Both arguments describe spatial multiplexing from different viewpoints.
Also, without specifying exactly what performance options are enabled, you really can't say what is happening over the third antenna in a 3x3:2 setup. For example, is Beam Forming enabled and working? Are these /n devices using HT Duplicate (MCS 32) ? MRC ?
Specifying all of the parameters can be tiresome, but IMO necessary when you want to discuss functional/performance issues..
Thank you for elaborating more on this. Interesting stuff. Is there any good whitepaper or article you can recommend on MIMO and SS? I found few online but nothing impressive so far.