Parameter to improve PDCP SDU delay

4G LTE
1

Hello All.
Do we have any parameter to improve PDCP SDU delay?

2

Caused by high RLC/MAC PDU retransmission ratio.

Now retransmission can be caused by a variety of problems:

  1. High resource block utilization / queuing

  2. Poor coverage - high initial BLER and high Aggregation later PDCCH

  3. Poor transmission - IPPATH or TWAMP lost messages

3

Thanks @Benjamin_Ng_aru.
Can we have any parametric solutions for 2nd cause?

4

How point no 1 cause pdcp delay?
Give some idea please.

5

Yes. Kindly search your vendor kpi related to initial BLER and Aggregation Layer PDCCH (the higher the value the poorer the RF and/or high users).

6

I have seen it in the field - however I still dont have concrete interpretation.
Maybe you can map PRB Utilization / Users per TTI (primary axis) vs PDCP SDU delay (secondary axis) and you shall see the graph is linear then tails exponentially.

7

Hi, we can minimize RF end latency by parameter tuning, most effective is With Huawei vendor is to use Pre-Allocatiom (here we are used smart preallocation) this feature will Pre-Allocate resources for uplink scheduling which improves RF end latency much, while Upliink resource usage will be increased, and you will see decrease in user uplink throughput ( but that will be statistical issue) real end uplink throughput wont impacted.
If you require i can suggest some Parameter Tuning in this regards

8

Please suggest some more parameters for Huawei if you can

9

Hello all.

If PDCP_SDU_DELAY_DL_DTCH_MEAN increased, then it will impact to any KPI of network?

Vendor is Ericsson.