7.8 KiB
LDPC coder/decoder implementation
The LDPC coder and decoder are implemented in a shared library, dynamically loaded at run-time using the oai shared library loader. The code loading the LDPC library is in nrLDPC_load.c, in function load_nrLDPClib, which must be called at init time.
Selecting the LDPC library at run time
By default the function int load_nrLDPClib(void) looks for libldpc.so, this default behavior can be changed using the oai loader configuration options in the configuration file or from the command line as shown below:
Examples of ldpc shared lib selection when running nr softmodem's:
loading libldpc_optim8seg.so instead of libldpc.so:
./nr-softmodem -O libconfig:gnb.band78.tm1.106PRB.usrpx300.conf:dbgl5 --loader.ldpc.shlibversion _optim8seg
.......................
[CONFIG] loader.ldpc.shlibversion set to default value ""
[LIBCONFIG] loader.ldpc: 2/2 parameters successfully set, (1 to default value)
[CONFIG] shlibversion set to _optim8seg from command line
[CONFIG] loader.ldpc 1 options set from command line
[LOADER] library libldpc_optim8seg.so successfully loaded
........................
loading libldpc_cl.so instead of libldpc.so:
make ldpc_cl
cp ../../../openair1/PHY/CODING/nrLDPC_decoder/nrLDPC_decoder_kernels_CL.cl
./nr-softmodem -O libconfig:gnb.band78.sa.fr1.106PRB.usrpb210.conf:dbgl5 --rfsim --rfsimulator.serveraddr server --sa --log_config.gtpu_log_level info --loader.ldpc.shlibversion _cl
------------------------------------------------
[HW] Platform 0, OpenCL profile FULL_PROFILE
[HW] Platform 0, OpenCL version OpenCL 2.1 LINUX
[HW] Device 0 is available
[HW] Device 0, type 2 = 0x00000002: cpu
[HW] Device 0, number of Compute Units: 8
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 8192
[HW] Device 0, max Work Items size for dimension: 1 8192
[HW] Device 0, max Work Items size for dimension: 2 8192
[New Thread 0x7fffcc258700 (LWP 3945123)]
[New Thread 0x7fffc3e57700 (LWP 3945124)]
[New Thread 0x7fffcbe57700 (LWP 3945125)]
[New Thread 0x7fffcba56700 (LWP 3945126)]
[New Thread 0x7fffcb254700 (LWP 3945128)]
[New Thread 0x7fffcb655700 (LWP 3945127)]
[New Thread 0x7fffcae53700 (LWP 3945129)]
[HW] Platform 1, OpenCL profile FULL_PROFILE
[HW] Platform 1, OpenCL version OpenCL 2.0 beignet 1.3
[New Thread 0x7fffc965a700 (LWP 3945130)]
[Thread 0x7fffc965a700 (LWP 3945130) exited]
[HW] Device 0 is available
[HW] Device 0, type 4 = 0x00000004: gpu
[HW] Device 0, number of Compute Units: 20
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 512
[HW] Device 0, max Work Items size for dimension: 1 512
[HW] Device 0, max Work Items size for dimension: 2 512
-----------------------------------------------------------------
./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 --rfsim --sa -O libconfig:/usr/local/oai/conf/nrue_sim.conf:dbgl5 --nokrnmod --loader.ldpc.shlibversion _cl --log_config.hw_log_level info
............................................................
[CONFIG] loader.ldpc 1 options set from command line
[LOADER] library libldpc_cl.so successfully loaded
[HW] Platform 0, OpenCL profile FULL_PROFILE
[HW] Platform 0, OpenCL version OpenCL 2.1 LINUX
[HW] Device 0 is available
[HW] Device 0, type 2 = 0x00000002: cpu
[HW] Device 0, number of Compute Units: 8
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 8192
[HW] Device 0, max Work Items size for dimension: 1 8192
[HW] Device 0, max Work Items size for dimension: 2 8192
[New Thread 0x7fffecccc700 (LWP 3945413)]
[New Thread 0x7fffec8cb700 (LWP 3945415)]
[New Thread 0x7fffec4ca700 (LWP 3945414)]
[New Thread 0x7fffdf7fd700 (LWP 3945417)]
[New Thread 0x7fffdfbfe700 (LWP 3945418)]
[New Thread 0x7fffdffff700 (LWP 3945416)]
[New Thread 0x7fffd73fc700 (LWP 3945419)]
[HW] Platform 1, OpenCL profile FULL_PROFILE
[HW] Platform 1, OpenCL version OpenCL 2.0 beignet 1.3
[New Thread 0x7fffde105700 (LWP 3945420)]
[Thread 0x7fffde105700 (LWP 3945420) exited]
[HW] Device 0 is available
[HW] Device 0, type 4 = 0x00000004: gpu
[HW] Device 0, number of Compute Units: 20
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 512
[HW] Device 0, max Work Items size for dimension: 1 512
[HW] Device 0, max Work Items size for dimension: 2 512
------------------------------------------------------------
```
A mechanism to select ldpc implementation is also available in the ldpctest phy simulator via the -voption, which can be used to specify the version of the ldpc shared library to be used.
Examples of ldpc shared lib selection when running ldpctest:
Loading libldpc_cuda.so, the cuda implementation of the ldpc decoder:
Initializing random number generator, seed 0
block length 8448:
n_trials 1:
SNR0 -2.000000:
[CONFIG] get parameters from cmdline , debug flags: 0x00400000
[CONFIG] log_config: 2/3 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
log init done
[CONFIG] loader: 2/2 parameters successfully set
[CONFIG] loader.ldpc: 1/2 parameters successfully set
[LOADER] library libldpc_cuda.so successfully loaded
...................................
```
Loading libldpc_cl.so, the opencl implementation of the ldpc decoder:
make ldpc_cl
cp ../../../openair1/PHY/CODING/nrLDPC_decoder/nrLDPC_decoder_kernels_CL.cl
./ldpctest -v _cl
Initializing random number generator, seed 0
block length 8448:
n_trials 1:
SNR0 -2.000000:
[CONFIG] get parameters from cmdline , debug flags: 0x00400000
[CONFIG] log_config: 2/3 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
log init done
[CONFIG] loader: 2/2 parameters successfully set
[CONFIG] loader.ldpc: 1/2 parameters successfully set
[LOADER] library libldpc_cl.so successfully loaded
[HW] Platform 0, OpenCL profile FULL_PROFILE
[HW] Platform 0, OpenCL version OpenCL 2.1 LINUX
[HW] Device 0 is available
[HW] Device 0, type 2 = 0x00000002: cpu
[HW] Device 0, number of Compute Units: 8
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 8192
[HW] Device 0, max Work Items size for dimension: 1 8192
[HW] Device 0, max Work Items size for dimension: 2 8192
[HW] Platform 1, OpenCL profile FULL_PROFILE
[HW] Platform 1, OpenCL version OpenCL 2.0 beignet 1.3
[HW] Device 0 is available
[HW] Device 0, type 4 = 0x00000004: gpu
[HW] Device 0, number of Compute Units: 20
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 512
[HW] Device 0, max Work Items size for dimension: 1 512
[HW] Device 0, max Work Items size for dimension: 2 512
................................
```
LDPC libraries
Libraries implementing the LDPC algorithms must be named libldpc<_version>.so, they must implement three functions: nrLDPC_initcall nrLDPC_decod and nrLDPC_encod. The prototypes for these functions is defined in nrLDPC_defs.h.
libldpc_cuda.sohas been tested with the ldpctest executable, usage from the softmodem's has to be tested.
libldpc_clis under development.