Add documentation for nFAPI

2025-01-27 10:59:40 +01:00
parent 48d52fdf42
commit 03b63257f2
5 changed files with 142 additions and 58 deletions
@@ -145,8 +145,8 @@ In the last lines:
 ## Split-related options (running in a DU)
-See [nFAPI documentation](../L2NFAPI.md) or [Aerial
+See [nFAPI documentation](../nfapi.md) or [Aerial
-tutorial](../Aerial_FAPI_Split_Tutorial.md) for information about the FAPI
+tutorial](../Aerial_FAPI_Split_Tutorial.md) for information about the (n)FAPI
 split.
 See [F1 documentation](../F1-design.md) for information about the F1 split.
@@ -57,7 +57,8 @@ There is some general information in the [OpenAirInterface Gitlab Wiki](https://
 - [How to use the L2 simulator](./L2NFAPI.md)
 - [How to use the OAI channel simulator](../openair1/SIMULATION/TOOLS/DOC/channel_simulation.md)
 - [How to use multiple BWPs](./RUN_NR_multiple_BWPs.md)
- [How to run OAI-VNF and OAI-PNF](./RUN_NR_NFAPI.md) _Note: does not work currently_
+- [How to run OAI-VNF and OAI-PNF](./nfapi.md): how to run the nFAPI split,
  including some general remarks on FAPI/nFAPI.
 - [How to use the positioning reference signal (PRS)](./RUN_NR_PRS.md)
 - [How to use device-to-device communication (D2D, 4G)](./d2d_emulator_setup.txt)
 - [How to run with E2 agent](../openair2/E2AP/README.md)
@@ -1,54 +0,0 @@
 # Procedure to run nFAPI in 5G NR
 ## Contributed by 5G Testbed IISc 
 ### Developers: Gokul S, Mahesh A, Aniq U R
 ## Procedure to Build gNB and UE
 The regular commands to build gNB and UE can be used
 ```
 sudo ./build_oai --gNB --nrUE
 ```
 ## Procedure to run NR nFAPI using RF-Simulator
 ### Bring up another loopback interface
 If running for the first time on your computer, or you have restarted your computer, bring up another loopback interface with this command:  
 sudo ifconfig lo: 127.0.0.2 netmask 255.0.0.0 up
 ### VNF command
 ```
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-LTE-EPC/CONF/rcc.band78.tm1.106PRB.nfapi.conf --nfapi VNF --noS1 --phy-test
 ```
 ### PNF command
 ```
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-LTE-EPC/CONF/oaiL1.nfapi.usrpx300.conf --nfapi PNF --rfsim --phy-test --rfsimulator.serveraddr server
 ```
 ### UE command
 ```
 sudo ./nr-uesoftmodem --rfsim --phy-test -d --rfsimulator.serveraddr 127.0.0.1
 ```
 ## Procedure to run NR nFAPI using Hardware (tested with USRP x310)
 ### VNF command
 ```
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-LTE-EPC/CONF/rcc.band78.tm1.106PRB.nfapi.conf --nfapi VNF --noS1 --phy-test
 ```
 ### PNF command
 ```
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-LTE-EPC/CONF/oaiL1.nfapi.usrpx300.conf --nfapi PNF --phy-test
 ```
 ### UE command
 ```
 sudo ./nr-uesoftmodem --usrp-args "addr=*USRP_ADDRESS*,clock_source=external,time_source=external" --phy-test
 ```
@@ -2,7 +2,7 @@
 OAI uses/supports a number of environment variables, documented in the following:
- `NFAPI_TRACE_LEVEL`: set the nfapi custom logging framework's log level; can be one of `error`, `warn`, `note`, `info`, `debug`
+- `NFAPI_TRACE_LEVEL`: set the nfapi custom logging framework's log level; can be one of `error`, `warn`, `note`, `info`, `debug`. Default is `warn`.
 - `NR_AWGN_RESULTS_DIR`: directory containing BLER curves for L2simulator channel modelling in SISO case
 - `NR_MIMO2x2_AWGN_RESULTS_DIR`: directory containing BLER curves for L2simulator channel modelling in 2x2 MIMO case
 - `NVRAM_DIR`: directory to read/write NVRAM data in (5G) `nvram` tool; if not defined, will use `PWD` (working directory)
@@ -0,0 +1,137 @@
 This document describes the SmallCellForum (SCF) (n)FAPI split in 5G, i.e.,
 between the MAC/L2 and PHY/L1.
 The interested reader is recommended to read a copy of the SCF 222.10
 specification ("FAPI"). This includes information on what is P5, P7, and how
 FAPI works. The currently used version is SCF 222.10.02, with some messages
 upgraded to SCF 222.10.04 due to bugfixes in the spec. Further information
 about nFAPI can be found in SCF 225.2.0.
 # Quickstart
 Compile OAI as normal. Start the CN and make sure that the VNF configuration
 matches the PLMN/IP addresses. Then, run the VNF
    sudo NFAPI_TRACE_LEVEL=info ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb-vnf.sa.band78.106prb.nfapi.conf --nfapi VNF
 Afterwards, start and connect the PNF
    sudo NFAPI_TRACE_LEVEL=info ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb-pnf.band78.rfsim.conf --nfapi PNF --rfsim
 Finally, you can start the UE (observe the radio configuration info in the
 VNF!)
    sudo ./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 -O ue.conf
 You should not observe a difference between nFAPI split and monolithic.
 # Status
 All FAPI message can be transferred between VNF and PNF. This is because OAI
 uses FAPI with its corresponding messages internally, whether a split is in use
 or not.
 The nFAPI split mode supports any radio configuration that is also supported by
 the monolithic gNB, with the notable exceptions that only numerologies of 15kHz
 and 30kHz (mu=0 and mu=1, respectively) are supported.
 The VNF requests to be notified about every slot by the PNF. No delay
 management is employed as of now; instead, the PNF sends a Slot.indication to
 the VNF in every slot (in divergence from the nFAPI spec). 
 Currently, downlink transmissions work the same in monolithic and nFAPI. In
 uplink, we observe an increased number of retransmissions, which limits the MCS
 and hence the achievable throughput (which is limited to 10-20Mbps). We are still
 debugging the root cause of this.
 After stopping the PNF, you also have to restart the VNF.
 When using RFsim, the system might run slower than in monolithic. This is
 because the PNF needs to slow down the execution time of a specific slot,
 because it has to send a Slot.indication to the VNF for scheduling.
 # Configuration
 Both PNF and VNF are run through the `nr-softmodem` executable. The type of
 mode is switched through the `--nfapi` switch, with options `MONOLITHIC`
 (default if not provided), `VNF`, `PNF`.
 If the type is `VNF`, you have to modify the `MACRLCs.tr_s_preference`
 (transport south preference) to `nfapi`. Further, configure these options:
 - `MACRLCs.remote_s_address` (remote south address): IP of the PNF
 - `MACRLCs.local_s_address` (local south address): IP of the VNF
 - `MACRLCs.local_s_portc` (local south port for control): VNF's P5 local port
 - `MACRLCs.remote_s_portc` (remote south port for data): PNF's P5 remote port
 - `MACRLCs.local_s_portd` (local south port for control): VNF's P5 local port
 - `MACRLCs.remote_s_portd` (remote south port for data): PNF's P7 remote port
 Note that any L1-specific section (`L1s`, `RUs`,
 RFsimulator-specific/IF7.2-specific configuration or other radios, if
 necessary) will be ignored and can be deleted.
 If the type is `PNF`, you have to modify modify the `L1s.tr_n_preference`
 (transport north preference) to `nfapi`. Further, configure these options:
 - `L1s.remote_n_address` (remote north address): IP of the VNF
 - `L1s.local_n_address` (local north address): IP of the PNF
 - `L1s.local_n_portc` (local north port for control): PNF's P5 local port
 - `L1s.remote_n_portc` (remote north port for control): VNF's P5 remote port
 - `L1s.local_n_portd` (local north port for data): PNF's P7 local port
 - `L1s.remote_n_portd` (remote north port for data): VNF's P7 remote port
 Note that this file should contain additional, L1-specific sections (`L1s`,
 `RUs` RFsimulator-specific/IF7.2-specific configuration or other radios, if
 necessary).
 To split an existing config file `monolithic.conf` for nFAPI operation, you
 can proceed as follows:
 - copy `monolithic.conf`, which will be your VNF file (`vnf.conf`)
 - in `vnf.conf`
  * modify `MACRLCs` section to configure south-bound nFAPI transport
  * delete `L1s`, `RUs`, and radio-specific sections.
  * in `gNBs` section, increase the `ra_ResponseWindow` by one to extend the RA
    window: this is necessary because the PNF triggers the scheduler in the VNF
    in advance, which might make the RA window more likely to run out
 - copy `monolithic.conf`, which will be your PNF file (`pnf.conf`)
 - in `pnf.conf`
  * modify `L1s` section to configure north-bound nFAPI transport (make sure it
    matches the `MACRLCs` section for `vnf.conf`
  * delete all the `gNBs`, `MACRLCs`, `security` sections (they are not needed)
 - if you have root-level options in `monolithic.conf`, such as
  `usrp-tx-thread-config` or `tune-offset`, make sure to to add them to
  `pnf.conf`, or provide them on the command line for the PNF.
 - to run, proceed as described in the quick start above.
 Note: all L1-specific options have to be passed to the PNF, and remaining
 options to the VNF.
 # nFAPI logging system
 nFAPI has its own logging system, independent of OAI's. It can be activated by
 setting the `NFAPI_TRACE_LEVEL` environment variable to an appropriate value;
 see [the environment variables documentation](./environment-variables.md) for
 more info.
 To see the (any) periodical output at the PNF, define `NFAPI_TRACE_LEVEL=info`.
 This output shows:
 ```
 41056.739654 [I] 3556767424: pnf_p7_slot_ind: [P7:1] msgs ontime 489 thr DL 0.06 UL 0.01 msg late 0 (vtime)
 ```
 The first numbers are timestamps. `pnf_p7_slot_ind` is the name of the
 functions that prints the output. `[P7:1]` refers to the fact that these are
 information on P7, of PHY ID 1. Finally, `msgs ontime 489` means that in the
 last window (since the last print), 489 messages arrived at the PNF in total.
 The combined throughput of `TX_data.requests` (DL traffic) was 0.06 Mbps; note
 that this includes SIB1 and other periodical data channels. In UL, 0.01 Mbps
 have been sent through `RX_data.indication`. `msg late 0` means that 0 packets
 have been late. _This number is an aggregate over the total runtime_, unlike
 the other messages. Finally, `(vtime)` is a reminder that the calculations are
 done over virtual time, i.e., frames/slots as executed by the 5G Systems. For
 instance, these numbers might be slightly higher or slower in RFsim than in
 wall-clock time, depending if the system advances faster or slower than
 wall-clock time.