What RBG-size values in PDSCH Config means?

Hello Experts,

What RBG-size values in pdsch config means?
It can have 2 values: config1 and config 2. What exactly means those 2 values?
RBG size can be between 2 to 16 PRBs, so how can it fetch only in 2 values either config1 or config2?

We have two type of resource allocation, resource allocation type 0 and resource allocation type 1,when we use RA type 0 in that scenario we will use as per 3GPP standard table, means assign the allocated RBGs which is determined by BWP size, and ra configuration,here we have two config, config1 and config2, default is config1 , but if scheduling grant is recieved with DCI 1_0, then we will use resource allocation type1.

Type 0 is bitmapped resource allocation, here UE provided a bitmap indication , which resource block are allocated for pdsch or pusch.
As NR support 275 PRB, so 275 bits if frequency romain resource allocation .
Due to this reason may be scheduling message have too much overhead.
That’s why in 38.214 they have resource block groups.
Now we have 2-16 PRBS.
It means when we have 2 PRbs we have 1-36 resource block.
Like uptoo 275 resource block.

For 275 resoruce blocks RBG-size is then 16 PRBs no matter if config1 or config2.

Yes, but config2 only applicable when scheduling grant recieved with DCI 1_0.
But if see the diagram 16 PRBs applicable for both 73-144 and 144-275.

Is this PDSCH configuration with above 3gpp table applicable only when I define bandwidth part?

Yes, only Active BWP.

What if without BWP part configuration?
As PDSCH scheduling is per slot based and without multislot scheduling one UE per slot can be scheduled what is the meaning of FD scheduling in that case?

RBG is the resource block group size when PDSCH has resource allocation type 0.

Type 0 resource allocation has distributed PRB allocation for UE. This distribution is based on the PRB group.
PRB group size depends on BW.
UE knows the BW and it also knows about DMRS configuration type signaled in DCI, so it calculates the REG size.

Distributed PRB allocation gives benefit of frequency diversity to the UEs
And also it helps in better resource allocation.

REG size depends on BW and it increase as BW increase.
Like if BW is 1-36 it is 2.

Thank you all guys. All clear now. :wink:

This figure is slightly misleading since UEs can also have distributed PRG allocation, which is the main motivation for resource allocation type 0.

It depends on BWP.
For me is clear the figure.
RBG size can be 2,4,8,16 depending on RBG-size param and BWP size.

Yes, that’s the understanding I also got from it.