# OAI accelerated by T1 card
###### tags: `Construction`

## Pre-requisites
| OS/Kernel | Version |
|:-------------------------- |:----------------------------------------|
| Host operating system | Linux Ubuntu 18.04 LTS |
| Kernel | 4.15.0.142.lowlatency |

## Build Environment
* Install git and other utility packages.

$ sudo apt-get install git vim ssh subversion gitk -y

* Install lowlatency kernel

$ sudo apt-get install linux-image-4.15.0.142-lowlatency -y

* Let the lowlatency kernel generate the build folder

$ sudo apt-get install linux-headers-4.15.0.142-lowlatency -y

* Reboot and setting the kernel as low latency mode

$ sudo reboot 
# Press shift+esc to enter GNU GRUB
# Choose Advanced options for Ubuntu --> choose low latency kernel (without recovery mode)

* Check the current kernel is the low-latency one

$ uname -a

* Do: apt update in order to let the machine is up-to-date

$ sudo apt-get update

* Plug-in the T1 accelerator card to the motherboard & Confirm to read the acceleator card

$ lspci | grep Xilinx

* After Plug-in and confirm it should show:
**3b:00.0 Serial controller: Xilinx Corporation Device 8038**

## Install and load FPGA LDPC driver

### Build driver

* **Step 1:** Cloning related project

$ git clone -b OpinConnect_NYCU_NTUST_fpga_ldpc_decoder https://gitlab.eurecom.fr/oai/openairinterface5g.git

* **Step 2:** Install kernel module driver

$ cd openairinterface5g/openair1/PHY/NR_TRANSPORT/xdma_driver/xdma
$ sudo make clean 
$ sudo make install

* <font color=#FF0000> **Here you may ran into this problem. If no, please skip to step 3 (Due to missing a signing key to sign the module)** </font>

SSL error:02001002:system library:fopen:No such file or directory: bss_file.c:175
SSL error:2006D080:BIO routines:BIO_new_file:no such file: bss_file.c:178
sign-file: certs/signing_key.pem: No such file or directory

* <font color=#FF0000> **To solve this problem, you should create a signing key to sign the module** </font>

$ cd /lib/modules/$(uname -r)/build/certs

$ sudo tee x509.genkey > /dev/null << 'EOF'
[ req ]
default_bits = 4096
distinguished_name = req_distinguished_name
prompt = no
string_mask = utf8only
x509_extensions = myexts
[ req_distinguished_name ]
CN = Modules
[ myexts ]
basicConstraints=critical,CA:FALSE
keyUsage=digitalSignature
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid
EOF

$ sudo openssl req -new -nodes -utf8 -sha512 -days 36500 -batch -x509 -config x509.genkey -outform DER -out signing_key.x509 -keyout signing_key.pem

* **Step 3:** Loading driver

$ cd openairinterface5g/openair1/PHY/NR_TRANSPORT/xdma_driver/tests
$ sudo ./load_driver.sh

* **Step 4:** Compile OAI

$ cd openairinterface5g
$ source oaienv
$ cmake_targets

# First time build 
$ sudo ./build_oai -I

# Simulation build
$ sudo ./build_oai -c -C -P

### Current related configuration

* Number of RB : 106
* Number of symbols : 12
* MCS : 9
* Frequency Band : 78 (DL frequency 3619080000: band 78, UL frequency 3619080000)
* Bandwidth : 40
* SCS : 30khz

* **Step 5:** Execute OAI (for simulation)

$ sudo ./phy_simulators/build/nr_ulsim -n10000 -m9 -r106 -s10 -w2 -y2 -z2 -P -o 

# -n : Number of trials to simulate
# -m : MCS value
# -r : number of RB
# -s : SNR
# -w : Start PRB for PUSCH
# -y : Number of TX antennas used in gNB
# -z : Number of RX antennas used in UE
# -P : Print ULSCH performances
# -o : Enabled FPGA module (default is disabled)
# -u : numerology

## Experiment Result
* Offload on FPGA
* Decoding in x86 (12th Gen Intel® Core™ i7-12700 × 20 )