Reimplement nFAPI message exchange between L1 and L2 following the
changes in parent commit removing msgDataTx.
Avoid direct calls and use NR_IF_module fptrs to avoid linking problems.
allowing to remove some function definitions that are not needed.
Note: after this commit, monolithic works but nFAPI operation is broken
and fixed in the next commit, to keep the changes small(er). All
simulators work.
This commit removes the use of msgDataTx's intermediate buffers for FAPI
messages and the call of the "Schedule response". The latter incurs an
additional copy of FAPI messages for the TX chain (for the RX chain, it
is and will remain there) which we can avoid.
Instead, it uses an NR_Sched_Rsp_t-typed variable sched_response to
store the results of the scheduler when called from tx_func(). Thus, the
scheduler remains unchanged (it gets a pointer to where to put FAPI
messages), but we don't call nr_schedule_response() to then copy FAPI
messages into the L1, but have them in a local variable sched_response.
sched_response on on the data segment, as it is big and would overflow
the stack; at the same time, this is ok because only one tx_func() runs
at a time.
Since we don't use allocate_sched_response() anymore, we don't need
deref_sched_response().
clear_slot_beamid() is moved to tx_func(), as it was called in
nr_schedule_response().
Since the "intermediate" NR_gNB_DLSCH_t structure groups both the
DL_tti_pdsch and TX_data.req structures, a pointer has been created to
point to pdsch_pdu. This affects a number of simulators, as they have to
put some messages on the stack:
- nr_dlschsim: put the corresponding variable on the stack
- nr_pbchsim: a new array for the SSB PDUs has been introduced
Further, these changes are now necessary:
- nr_dlsim: there were variables "rel15" and "pdsch_pdu_rel15" that
point to the same PDSCH PDU. At least "rel15" would not exist, as the
corresponding pointer is now populated in phy_procedures_gNB_TX(), and
we therefore refer to the single PDSCH PDU variable with
"pdsch_pdu_rel15", but at the place where "rel15" used to be
initialized.
- nr_ulsim: use nr_save_ul_tti_req() to load PDUs into the RX chain
instead of nr_schedule_response(), which does not exist anymore.
Use UL_INFO on the stack, to simplify the code. move in the same struct
the associated rach, pdu, crc, srs arrays that where pointed from
directly in gNB structure Keep in nfapi the existing logic that make
malloc for theses rach, pdu, crc, srs array lists
Pass only relevant fields, where appropriate.
Co-authored-by: Robert Schmidt <robert.schmidt@openairinterface.org>
nr_fill_indication() fills CRC and RX requests, to be sent from L1 to
L2. Before this commit, nr_fill_indication() is called when
- we finally decoded LDPC (or not)
- low signal on PUSCH
This might happen at the same time, i.e., nr_fill_indication() might try
to fill both CRC and RX, in the same list, from different threads. This
can lead to this assertion:
Assertion (crc->rnti == rx->rnti) failed!
In handle_nr_ulsch() ../../../openair2/NR_PHY_INTERFACE/NR_IF_Module.c:190
mis-match between CRC RNTI e071 and RX RNTI 5e3b
e.g., e071 is low energy, and while 5e3b related message are filled in
one thread, e071 is being put into the message structure as well.
At least that is my understanding. I could not actually reproduce this
assertion; to be seen if it still happens.
The next commit introduces a separate gNB TX processing thread. To
properly separate DL scheduler (for scheduling decisions) from UL
indication handling (for UL packets), this commit introduces a slot
indication "tick" to run the DL scheduler which will be put into the gNB
TX processing chain instead of the UL indication.
remove several unused files
remove mem_block_t that is never used in a different way than a simple heap buffer
move up IP address type and remove duplications of the same struct declaration
This commit fixes a bug caused by global variables in the gNB_MAC_INST
structure used to transfer MAC scheduler's results to the PHY layer.
When using several threads in the PHY layer, it may happen that the
MAC scheduler is called a second time by the second PHY thread for the
next slot before the content of the global variables in the gNB_MAC_INST
structure used to store the result of the MAC scheduler for the current
slot have been consumed by the first thread, leading to unpredictable
results (all of them certainly wrong).
The solution is to introduce a small memory management module for the
interface between the PHY threads and the MAC scheduler. The MAC
scheduler now fills the data structures passed to it, and not a
global variable anymore. The PHY layer manages the structures and
ensures that no data is overwritten before being fully consumed by
the various threads of the PHY layer.
Some care has to be taken because several PHY threads will access the
same structures at the same time for a given slot (in read mode, so
it's okay). A mechanism of reference counting has thus been introduced.
Only one CC is supported. This restriction should not be too hard
to remove if/when needed. (The code before this commit does not seem
to work for more than one CC anyway.)
The simulators have been changed: due to linker errors that would arise
otherwise, a lot of functions are defined in them to avoid such errors.
Some functions are also defined in header files; in this commit, we
define most functoins in nr_dummy_functions.c, which is compiled in, not
by including the C file, but by adding it to the target in
CMakeLists.txt
- nr_dlsim+nr_ulsim need NR_IF_Module_init(), so it cannot be in
nr_dummy_functions, but the others need it
- Link correcr NR_IF_Module_init() into these simulators, and reduce
overall link list
- Correctly link remaining simulators
This commit provides CSI reporting support
which is required for MIMO. It also updates
the configuration files, provides sample BLER
simualtion files for packet dropping in the
MIMO 2x2 case. It also includes the hooks
and functions (e.g., updating UCI2_3_4 PDU field)
for MIMO 2x2 support. This commit will not include
any channel abstraction code or modelling.
Robert Schmidt