Shared object file *libldpc_t2.so* is created during the compilation. This object is conditionally compiled. Selection of the library to compile is done using *--build-lib ldpc_t2*. Example command to build OAI with support for LDPC offload to T2 card is:
Path to the PMD for operating the card is specified in `CMakeLists.txt` file in
*LDPC OFFLOAD library* section. Modify following line based on the location of
Shared object file *libldpc_t2.so* is created during the compilation. This object is conditionally compiled. Selection of the library to compile is done using *--build-lib ldpc_t2*.
*Required poll mode driver has to be present on the host machine and required DPDK version has to be installed on the host, prior to the build of OAI*
*Required poll mode driver has to be present on the host machine and required DPDK version has to be installed on the host, prior to the build of OAI*
# 5G PHY simulators
## nr_ulsim test
## nr_ulsim test
Offload of the channel decoding to the AMD Xilinx T2 card is in nr_ulsim specified by *-o* option. Example command for running nr_ulsim with LDPC decoding offload to the T2 card:
Offload of the channel decoding to the T2 card is in nr_ulsim specified by *-o* option. Example command for running nr_ulsim with LDPC decoding offload to the T2 card:
```
`sudo ./nr_ulsim -n100 -s20 -m20 -r273 -o`
cd ~/openairinterface5g
source oaienv
cd cmake_targets/ran_build/build
sudo ./nr_ulsim -n100 -s20 -m20 -r273 -R273 -o
```
## nr_dlsim test
## nr_dlsim test
Offload of the channel encoding to the AMD Xilinx T2 card is in nr_dlsim specified by *-c* option. Example command for running nr_dlsim with LDPC encoding offload to the T2 card:
Offload of the channel encoding to the AMD Xilinx T2 card is in nr_dlsim specified by *-c* option. Example command for running nr_dlsim with LDPC encoding offload to the T2 card:
```
`sudo ./nr_dlsim -n300 -s30 -R 106 -e 27 -c`
cd ~/openairinterface5g
source oaienv
## OTA and RFSIM test
cd cmake_targets/ran_build/build
Offload of the channel encoding and decoding to the AMD Xilinx T2 card is enabled by *--ldpc-offload-enable 1* option. Example command for running nr-softmodem with LDPC processing on the T2 card:
Offload of the channel encoding and decoding to the AMD Xilinx T2 card is enabled by *--ldpc-offload-enable 1* option.
Available LDPC implementations and loading particular libraries is well described in *openair1/PHY/CODING/DOC/LDPCImplementation.md*. Default library for LDPC processing is called `libldpc.so`. Sample command for running nr-softmodem with selected library (in this case we want to replace `libldpc.so` by `libldpc_optim.so` library):
- offload of the LDPC encoding implemented for MCS > 2, OAI CPU encoder is used for MCS =< 2
- offload of the LDPC decoding implemented only for MCS > 9, decoding of the smaller TBs on the T1 card leads to blocking of the card
- functionality of the LDPC encoding and decoding offload verified in OTA SISO setup with USRP N310 and Quectel RM500Q, blocking of the card reported for MIMO setup (2 layers)
- HARQ is not functional with LDPC decoding offload to the T1 card (restricted in the code to avoid blocking of the card)
- LDPC encoding offload not implemented for the T1 card
*Note: AMD Xilinx T1 Telco card is not supported anymore.*
- not supported in current develop branch, please checkout to *2023.w43*
### AMD Xilinx T2 card
- offload of the LDPC encoding implemented for MCS > 2
- occasional blocking of the card in decoder function - issue is investigated
