UL/DL PRB Utilization

[chaiwat]

Does anyone know why UL PRB Utilization is higher that DL PRB Utilization?

[sak2e]

It depend on user activity & channel configuration. If channel configs oke, then could be most users doing upload.


Does anyone know why UL PRB Utilization is higher that DL PRB Utilization?

[chaiwat]

Thanks "yoyokdp" but your answer is too general. can you explain further about what kind of configuration because its always higher than DL prb utilization for whole region. From characteristic of user, i don't think that users will use download lower than upload because it can be simply confirmed by comparing UL/DL traffic in specific period and its obvious

[perimedes]

Dear Chaiwat, I'm affraid I cannot agree with you. Please, keep in mind that UL PRB utilization, as DL PRB utilization is commanded from the LTE scheduler. Schedulers, as it goes, are different by hardware providers. I have been testing extensively networks from E*** , Nokia and Huawei, and every provider has a scheduler flavor, but it does not mean UL PRB utilization being higher. In fact, I can provide you some examples where UL PRB utilization is lower consistently. And all is correct.

The real problem is that the scheduler is managing several parameters. Mainly PRB and time (in chunks of 2ms), but modulation and MIMO too, besides clients demands.

Choose a cell. If you plot data volume against time and % prb utilisation during a measuremente period, let's say a working day or a week, you will be able to get a signature from the cell that is kind of stable along time. If you compare DL and UL you would be able to establish some facts. Let's say that UL utilisation is higher than DL utilisation. Besides, time utilisation is more or less the same. My feeling would be that data users are more or les simetric traffic volume . You are experiencing more % utilization of UL PRB because uplink modulation is 16QAM single antenna, and downlink modulation is 64QAM 2x2 MIMO antenna and therefore the scheduler needs more prb on the uplink only to keep data traffic (Only a very common configuration, real reasons could vary).

Let´s say than now a new neighbour cell become active. This new cell put interferency on some uplink prb's of our former cell...Our old cell would react using more time and reducing %prb uplink utilisation.

On short: you will need to take in accout %PRB utilization, time (chunks of TTI during measurement period), effective MIMO class and effective modulation. Is not an easy task.

Regards.

[dkaloki]

Hey guys, what about a SISO case, from the explanation, but I think it is not exhaustive : Does the Coding Scheme distribution have anything to do with this even in SISO where UL PRB Utilization is more than DL PRB Utilization?

[rimeka]

probably L.ChMeas.PRB.UL.Used.Avg contain PUCCH usage also, not only PUSCH.

[kike]

Thanks "yoyokdp" but your answer is too general. can you explain further about what kind of configuration because its always higher than DL prb utilization for whole region. From characteristic of user, i don't think that users will use download lower than upload because it can be simply confirmed by comparing UL/DL traffic in specific period and its obvious

Chek transmition parameter, in our network we faced with that problem.

[sselmi]

Hi Chaiwat,
probably the UL PRBs allocation when no data is sent is related to pre-scheduling switch (Check PreallocationSwitch and SmartPreAllocationSwitch) :
"UL pre-allocation functionality allocates PUSCH RBs to the UE while the cell is in light load situation; even the UE's sending buffer is empty. It gives the UE the possibility to hit the sending chance quickly. For instance, this functionality can accelerate the ACK of a DL RRC signaling message"
Br//sselmi