fix(nrLDPC_decoder): fix numIter increment
The logs of ./nr_ulsim -n100 -m19 -s12 -S12 -z2 -L4 were showing that sometimes
the decoding of one segment was failing while the CRC check succeeded. This was
happening because the iteration counter numIter was not properly managed so that
when the last iteration was successful to decode the segment still numIter at
the exit was equal to numMaxIter plus 1 so that decoding was considered to have
failed. In other words the last iteration if it occured was always wasted.
This commit offers to solve this problem by simply moving the iteration counter
increment at the end of the iteration loop while remaining careful at fixing the
tests relying on this counter.
Post-Scriptum:
After a first review, we decided to make the counter more standard from a C code
perspective. The counter now counts from 0 to numMaxIter minus 1. If it reaches
numMaxIter, it means that decoding was unsuccessful.
The idea is to make LDPC iteration accounting more standard from a C coding perspective by making two changes:
1. Now the iteration counter starts at 0 for the first iteration and goes up to max_ldpc_iterations - 1 for the last iteration.
If it is equal to max_ldpc_iterations, it means that decoding failed.
2. A chain of useless returns in the UE DLSCH decoding call chain was removed.
Use `rfsimu_channel_ue1`, `rfsimu_channel_ue2`, etc. if you want to
use different channel models for each client. The client connection
order determines its channel model name.
Long PRACH extends beyond a slot. Changes necessary to mark future slots
that may contain prach in ru, phy and mac functions.
In RU, the PRACH IDFT is done only after receiving last slot and marks
for L1 to start processing. The L1 processes at the last prach slot and
reports to MAC with the first slot index.
In MAC scheduler, the VRB for future slots are also marked as used.
PRACH scheduler is called in advance one frame minus num prach slots.
Added new command line option to channelmod: noise_power_dBFS. This options
allows the user to configure noise power in dBFS added instead of the per-channel
value.
This makes it so noise is not accumulated per channel reaching higher than expected
values.
The dBFS unit allows easy configuration. The gNB by default uses -36 dBFS setting.
To reach 3dB SNR one should set the noise_power_dBFS value to -39.
To configure using command line use --channelmod.noise_power_dBFS -50. Using this
setting the gNB and nrUE connect without issue.
E1AP enc/dec lib improvements
This MR is including some fixes and improvements for the E1AP library,
focusing mostly on Bearer Context Management:
- struct reorganization: split setup and modification request messages
into distinct structures, ensuring compliance with 3GPP TS 38.463
specifications
- add encoding/decoding sub-functions for different IEs
- improvements to Bearer Context Management: Implemented various
improvements to the E1 Bearer Context Setup Response and Request,
including the adoption of encoding/decoding sub-functions for
different IEs
- use lib functions whenever need (e.g. cp_bearer_context_setup_request
in cucp_cuup_e1ap.c)
- handle optional struct members as pointers
- updated copy/equality check utility functions
EDIT: The MR is also including the changes from !3222 (closed):
> While testing E1 with security enabled for DRBs, it was found that
> data traffic was not functional.
>
> The problem was that security settings were modified in the PDCP
> reestablishment happening when receiving Bearer Context Modification
> Request.
>
> So some restructuring was done.
>
> The actual fix is in 18176297, the others are for support. Basically
> we introduce a boolean to check if the security settings are present in
> Bearer Context Modification Request and we change PDCP security settings
> only if they are.
>
> (Note that in OAI CU security settings are not sent in Bearer Context
> Modification Request, so we could also remove all this, but we need to
> be compatible with other cu-up and/or cu-cp.)
Bearer context setup request and modification request messages
differ in various IEs according to 9.2.2 of 3GPP TS 38.463, e.g.
the Bearer context setup request does not contain a list of
DRBs to modify and does not contain an UP TL configuration.
Thus, the goal of this commit is to split the setup request message
and the modification request into two different structs:
* adopt e1ap_bearer_mod_req_t where necessary (e.g. fill_e1_bearer_modif)
Also, reorganized existing struct members according to specs:
* remove irrelevant struct members from the setup request
* group members from the same IEs into structs
* set optional struct members IEs as pointers
* add and adopt enc/dec/cp/eq lib functions for single IEs
* add UP_TL_information_t struct with TEID and TL address info and adopt in stack
* use int instead of long for count types
* update the relevant copy/equality check utility functions
Extra:
* add a function to handle Security Information in RRC in the process
* add create_up_tl_info and adopt in unit tests
Changes to support multiple TDD patterns
- Updated the configuration changes for 2 Patterns
- Update the TDD table configuration for NFAPI
- Added the tdd bitmap for the period
- Adapted the bitmap for UL/DL for the multi TDD pattern
- Updated the RACH procedure for multi TDD pattern
- Updated DL and UL scheduler for multi TDD pattern
* assuming num_dl_slots and num_ul_slots are including also
slots with dl/ul symbols respectively
* refactor set_tdd_config_nr
* moved function to MAC
* fill max_num_of_symbol_per_slot_list depending on slot type
* use new set_tdd_config_nr in stack
* minor refactor in config.c to improve readability (scs)
Co-authored-by: Guido Casati <guido.casati@firecell.io>
Repair nFAPI in 5G
Add 5G nFAPI in OAI/Make it it work.
Many commits in this branch are basically bug fixes of things that don't work
properly, such as
- check for correct conditions (e.g. instance numbers in the RAN context)
- remove artificial limitation (e.g. only one PUCCH per TDD period in the PNF)
- improve performance (reduce big mallocs, make some static buffers such as a
global ring buffer for nFAPI messages in the PNF)
- fix bugs in nFAPI (e.g., increase maximum message size to ~64kB instead of
1500 bytes, because the latter is way too small for many TX_data.requests in
5G, and it will delay message arrival unduly)
- fix bugs in message enc/dec (e.g., handle FDD in config.request)
- adjust the L1 such that the condition "we run monolithic" is not necessery
(e.g., some message numbers in nFAPI struct where reset in MAC, instead of
L1, and this breaks when running the PNF)
There are instructions that explain how to set it up. Two CI tests have been
added, one with COTS UE and MIMO in DL+UL in TDD numerology 1 (30kHz), and a
second test with FDD mu=0 (15kHZ) in RFsimulator.
These were some old to-dos that have been addressed.
- test with COTS UE - 4x4 pipeline works good in DL, UL now also work
- test in RFsim
- make PNF status message
- make FDD in u0 work
The L1 receives a pointer to the L1 payload to use for PDSCH generation.
This would overwrite an existing pre-allocated pointer. Remove this
preallocation. Instead, allocate it in the simulator (the only place
that actively uses this buffer allocation; in nr-softmodem, it's lost by
assigning a pointer). Allocate with an extra byte, because the payload
(in bits) might not be a multiple of 8 bits/1 byte, so the CRC is in the
last 3 bytes.
Also, improve the log with frame/slot information if the PDSCH payload
pointer is NULL.
FAPI says these lists should be for MAX_TDD_PERIODICITY (which is maybe
a frame, or a TDD period? but likely not two frames). Reduce to one
frame.
Also, the nFAPI code assumes one entire frame, so use that (this commit
necessary to actually make the PNF work, otherwise, the
packing/unpacking of the FAPI message would need to do 2 frames).
Closes: #876
Use this function to implement distinct behavior for monolithic or PNF:
- monolithic: run the scheduler, as normal
- PNF: send a slot indication; the VNF will send an answer which the PNF
will handle elsewhere.
Add function declarations to make nr_ulsim compile, as NR_IF_Module.c is
part of the MAC sources. As of now, this is necessary; I think the right
way would be to take NR_IF_Module.c out of the MAC, and make this a
"glue" library that sticks L1 and L2 together, in monolithic (in VNF, in
that case, we should not link in L1, and for the PNF not the L2,
creating separate executables... Rome was not built in one day).
fix(nrLDPC_coding_t2): Miscellaneous fixes related to T2
1. HARQ combined offset:
The offset provided for each code block in the HARQ combined input and output
buffer shall not be above 512. A modulus was performed on the offset of the TB
in the buffer to avoid this situation. But the offset of the code block was
added afterward so that the total offset was sometimes going above 512.This
commit performs the modulus after adding the code block offset. Usually this
issue was triggering a segfault after less than 2 minutes of an iperf test on
some setup using T2. The same iperf test was successfully performed during 10
minutes on the same setup with this change.
2. Properly stop LDPC coding in gNB and UE:
LDPC coding was yet not properly stopped by using free_nrLDPC_coding_interface
in gNB and UE. This was not causing major issue until now. It was especially not
causing any issue with T2 LDPC coding using the PF. But using T2 VFs, if the
coding library is not properly stopped then the VF cannot be used anymore unless
the admin app is restarted. So this MR adds the missing free_nrLDPC_coding_interface.
LDPC coding was yet not properly stopped by using free_nrLDPC_coding_interface in gNB and UE.
This was not causing major issue until now. It was especially not causing any issue with T2 LDPC coding using the PF.
But using T2 VFs, if the coding library is not properly stopped then the VF cannot be used anymore unless the admin app is restarted.
So this MR adds the missing free_nrLDPC_coding_interface.
Introduce ITTI queue in RRC-to-MAC direction
resolve ue rcc to mac race conditions by a itti queue, but it doesn't
resolve the problem of exact slot we should apply the new cell
configurtion
Jaroslava Fiedlerova