Can PRB assignment be affected if the media on a link is limited?

Transport Networks
1

Hello Everyone.
Query: can PRB assignment be affected if the media on a link is limited?
Lke a site configured with 2 carriers (B1+B20) is not reaching max throughput infact limited at 80 Mbps (max available link capacity).
But what is surprising is that PRB assignment is not full.
PRB on Pcell are full but PRB on Scell are mostly around 10.
Appreciate for some explanation, even if it is mandated that TX capacity bottleneck impacts PRB assignment

3

What is bw for band used?
Tx backhaul I think put no limitation on PRB assignment.

4

BW is 20 + 10.

5

Ok, so Pcell 100 PRB allocated for SCell, you’re not getting 50 PRB allocated. Is it correct?

6

Yes, correct.

7

Transmission quality is much related to PRB allocation.
If TCP packet loss or low bandwidth, incoming data to enb is not enough, then the number of PDCCH assignment & number of average PRB is small, low throughput.

8

Why PRBs should be 100% occupied on Scell if link is capped at 80 Mbpsec?
Not even on PCell is not mandatory to be 100% occupied.

9

I need to understand how the eNB scheduler bridges the RF end with the Tx media part and based on that allocates the resources accordingly.

Shouldn’t the eNB scheduler schedules all the available RBs on RF end even if throughput is limited to a certain figure?

10

Why to use all RBs if throughput requirement is low?

11

Because the demand from UE is large data so based on demand all available resources logically should be assigned.

12

Here not sure.
For CQI condition, TBS index allocated to user.
Need to check per TTI for same then mapping of TBS index with PRB table.

13

UE demand doesn’t matter here.
All matter is how much data is there in eNB buffer to be scheduled.
If less RB can deliver that buffer, then no need to use all RBs.

14

So if for some reason, at one instant, for the same site, with same TX capacity, the buffered data somehow requires all PRBs to be scheduled, then the eNB irrespective of TX capacity will assign all PRBs.

Is that logical right?

Reason for above statement: in DT for some instants/periods full prb assignment was seen but that was like 5% of the session time.

15

Yes, correct.

16

Ok thanks for the clarification :+1:
What popped up in my mind is to configure lower MCS on the site and test the situation in that case I expect higher PRB Assignment as buffered data will grow high when MCS is downgraded.
Right?