The 1st DL slot have higher BLER than other DL slots

5G NR
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1

Hi all,
I found that there is an issue that BLER of the 1st is higher than that of others in a TDD (DDDFU) NR system.

Do you have any Idea?

2

DDDSU: first slots are 0-5-10-15 in 1 frame 20 slots.
First, you need to check bler of slots 0-5-10-15, which is high.
Any special channel,/signal configured on this slot.
Maybe it is due to UE capability mismatch with cell configuration in this slot, UE can not decode pdsch data on this slot, so bler is high.

3

All the first slot have higher than DL #1,2,3 (slog%5).
Several kinds of UE have the same pattern, so I think it is not the issue of a UE.

4

Hi Hainm, can you please explain why 0,5,10 are first transmission slot? What are assuming Harq retransmission 16?

5

Besides UE issue, slot 0 is the first DL slot after UL slot. I think RRU may have problems also.

6

Does this mean, that LteTdd aligned NR TDD frame structure has an advantage, when frame start was shifted by 3ms, because it has ony two first DL slots instead of four? (30 kHz SCS)

DD DD DD DS UU DD DD DD DS UU