Question about UL OFDMA support in 5G-LENA

[Bara Sabbah]

  Hello everyone,

 I have a question regarding the current status of OFDMA support in the uplink in 5G-LENA. Both the documentation and several code comments state that OFDMA in the UL is not implemented. However, when inspecting the code ( particularly NrMacSchedulerOfdma::AssignULRBG)  it appears that uplink OFDMA‑like behavior is present, with allocations in both time (symbols) and frequency (RBGs) being assigned to multiple UEs  (e.g., RB allocation across multiple UEs within the same symbol).

I am a bit confused about the status of OFDMA in the uplink. Is OFDMA actually implemented in the UL and the documentation simply not up to date, or am I missing something?


Best regards,
Bara

[Gabriel Ferreira]

OFDMA UL is there, but the logic is not the same as downlink. It needs to be updated.

[rene breloer]

Hello everyone,

I'd like to know if there was any update regarding this question. 

Were you able to udpate it Bara or the 5G-Lena Team?

Kind regards,

Rene

[Gabriel Ferreira]

Same as before. Priority up to this point has been on downlink.

[rene breloer]

Thank you for your fast reply.

Can you give hints on how to implement it ourselves and what could be the caveats when doing so?

[Gabriel Ferreira]

Sure. I think you basically need to do whatever we do for downlink, but for uplink. And also need to retain the ability to behave like LTE's SC-FDMA/DFT-s-OFDM.

[Gabriel Ferreira]

Just an addendum: we don't actually simulate to the OFDM symbol level, so SC-FDMA/CP-OFDMA will just change scheduling, but can end up not affecting performance. However that is not true in real systems (e.g. in terms of power).