<table style="border-collapse: collapse; border: none;"> <tr style="border-collapse: collapse; border: none;"> <td style="border-collapse: collapse; border: none;"> <a href="http://www.openairinterface.org/"> <img src="./images/oai_final_logo.png" alt="" border=3 height=50 width=150> </img> </a> </td> <td style="border-collapse: collapse; border: none; vertical-align: center;"> <b><font size = "5">OAI T1/T2 LDPC offload</font></b> </td> </tr> </table> **Table of Contents** [[_TOC_]] This documentation aims to provide a tutorial for AMD Xilinx T2 Telco card integration into OAI and its usage. ## Prerequisites Offload of the channel decoding was tested with the T2 card in following setup: **AMD Xilinx T2 card** - bitstream image and PMD driver provided by AccelerComm - DPDK 20.11.3 with patch from Accelercomm (also tested with DPDK 20.11.7 version) - tested on RHEL7.9, RHEL9.2, Ubuntu 20.04, Ubuntu 22.04 ## DPDK setup - check the presence of the card on the host - `lspci | grep "Xilinx"` - binding of the device with igb_uio driver - `./dpdk-devbind.py -b igb_uio <address of the PCI of the card>` - hugepages setup (10 x 1GB hugepages) - `./dpdk-hugepages.py -p 1G --setup 10G` *Note: Commands to run from dpdk/usertool folder* ## Compilation Deployment of the OAI is precisely described in the following tutorials. - [BUILD](https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/BUILD.md) - [NR_SA_CN5G_gNB_USRP_COTS_UE_Tutorial](https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/NR_SA_Tutorial_COTS_UE.md) 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: `./build_oai -P --gNB -w USRP --build-lib "ldpc_t2" --ninja` *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* ## 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: `sudo ./nr_ulsim -n100 -s20 -m20 -r273 -o` ## 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: `sudo ./nr_dlsim -n300 -s30 -R 106 -e 27 -c` ## OTA and RFSIM test 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: `./nr-softmodem -O config_file.conf --sa --ldpc-offload-enable 1` ### LDPC encoding/decoding with CPU/GPU 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): `./nr-softmodem -O config_file.conf --sa --loader.ldpc.shlibversion _optim` Available options: - --loader.ldpc.shlibversion _optim8seg - --loader.ldpc.shlibversion _optim - --loader.ldpc.shlibversion _orig - --loader.ldpc.shlibversion _cuda - --loader.ldpc.shlibversion _cl ## Limitations ### AMD Xilinx T1 card - 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 - 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 - 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