Yes, for beamforming 2 ssb required.
This is medium, that’s why 8 bit.
Then only beamforming supported.
But it still covers the whole sector and must be beamformed meaning that each of the 64 TX will have a different weight.
Otherwise how do you expect to get an ssb that covers whole sector with only 1 TX out of 64 TX?
Beamforming refer to 2 ssb or greater.
Then what is the use of having multiple ssb?
A higher gain for each ssb.
When 8 ssb gain is higher for each ssb.
But above you said different wait can be aplied.
Weren’t you mean gain here?
Required to defined shape of beam and for mu-mimo concept as well .
1 ssb = 2 layers
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The narrower the beam higher is the gain.
So for mu-mimo it’s precondition checked number of layers of user should be less then configured threshold of layers then rbg get multiplexed.
I mean if gain is achieved by narrower beam (hence multiple ssb), then what will be achived by aplying different weight with 64 TX?
It’s not different. Each of the 64 antenna elements will have a weight so that the beamformed shape will cover whole sector with 1 ssb.
With a lower gain than it would have with 8 ssb.
So do you mean beamforming gain is over and above gain achieved by 64/32 TX antenna weight applying.
Right?
Nope. When you aim to cover a single direction them gain is highest possible.
When you cover a large area by beamforming then gain is lower.
But it is still beamforming.
Idea is that everything is beamformed in 5G.
By playing weights of those 64 TX.
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For 5G, LTE there is tm8, tm9 there is 2 step weigh applied.
I.e. long and short term weights.
Weight applied are fixed if it’s on basis of cqi, ri, pmi ie csi
Weight applied vary if on basis of srs.
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Ok. Last question on this.
How does it decide in which direction to be beamformed?
Because its not user specific.
Is it done in all directions equally?
Weights for ssb comes from factory calibration.
For PDSCH weights are done based on PMI reporting.
Yes if it’s fixed GoB based.
It means gain is fix. And it would be in all direction.