The following was changed in this commit:
- A new struct in the mac instance was created
for all emulated L1 fields.
- NR UE RRC state bug was fixed
- Checking the RAR rnti based on the MAC instance
ra.ra_rnti and not hardcoding to 0x10b
- Modified the name of the new emulate_l2 flag
to make sense: emulate_l1
For multiple UEs, we need to be able to filter the rx'd messages by
the RNTI. However, we do not have the RNTI value until the CFRA (NSA)
or CBRA (SA) procedure is complete. The check below will handle this.
Also, depending on the RNTI value, we can have a SIB (0xffff), RAR (0x10b),
Msg3 (TC_RNTI) or an actual DCI message (CRNTI). When we get Msg3, the
MAC instance of the UE still has a CRNTI = 0. Only once the RA procedure
succeeds is the CRNTI value updated to the TC_RNTI.
1. The preamble index in the NRUE is random for SA.
Using the preamble index from the mac->ra is
correct.
2. The dl_pathloss calculated is from L1. We should
shunt this feature out for our emulated mode. If
we add the abstraction later, we can model the
pathloss in the proxy and update it in the RA
procedure of the NRUE.
3. Checking that the crnti != t_crnti is not valid
for SA mode. And may only be needed for multi-UE
in NSA mode. We might be able to delete it all
together. For now, we only use for NSA mode.
4. Checking the RAR based on rnti = 10b and not the
RA_STATE is better.
Also, in the nr_rrc_mac_config_req_ue(), we should
only be configuring L1 if we are not in the L2 emul
mode. We are crashing due to the RRC state in the NRUE
not being set/checked properly.
In this commit, we changed the stub function of the NRUE
to handle the MIB and SIB1, which arrive in a single
DL_TTI_REQ. If we have not received the MIB, we first
call the scheduler, then we handle any received NFAPI
messages. The NFAPI message handler will then call
the nr_ue_dl_indication() again, which will process
first the MIB, then SIB1. It seems that we are not
properly sending the SIB1 response back to the gNB so
the NRUE eventually crashes. We are however, properly
decoding the MIB and SIB which is a step in the right
direction!
In the previous commit, the NRUE would record
the time it received a slot and compare this
rx time to the next slot. If the next slot
came in before it had been 500us, the NRUE
would sleep a delta amount to make the duration
between the two slot indications 500 us. This
change complicated the code and did not
improve the performance so it was removed.
Furthermore, this commit removes the old
queueing mechanism of the slot indications and
uses calloc rather than an array.
Melissa Elkadi