udevlog/turbofec

TurboFEC - SIMD vectorized LTE turbo and convolutional encoders and decoders

About TurboFEC

TurboFEC is an implementation of LTE forward error correction encoders and decoders. Included are convolutional codes, turbo codes, and associated rate matching units that handle block interleaving, bit selection, and pruning.

Using x86 SIMD instructions, the convolutional and turbo decoders are currently the fastest implementations openly available. If you believe the preceding statement to be false, please contact the author to discuss further optimizations.

Convolutional decoding uses Intel SSE3, SSE4, and AVX2 instructions if available.

Turbo decoding requires Intel SSE3 or higher.

LTE specification and sections:

3GPP TS 36.212 "LTE Multiplexing and channel coding"

5.1.3.1 "Tail biting convolutional code"

5.1.3.2 "Turbo encoding"

5.1.3.1 "Rate matching for turbo coded transport channels"

5.1.3.2 "Rate matching for convolutionally coded transport channels and control information"

Compile

$ autoreconf -i
$ ./configure
$ make

Test

$ make check

A collection of GSM, LTE, and other forward error correcting codes will be tested.

=================================================
[+] Testing: GSM TCH/AHS 5.15
[.] Specs: (N=3, K=5, recursive, flushed, punctured)

[.] BER test:
[..] Testing:
[..] Input BER.......................... 0.007450
[..] Output BER......................... 0.000000
[..] Output FER......................... 0.000000

=================================================
[+] Testing: LTE PBCH
[.] Specs: (N=3, K=7, non-recursive, tail-biting, non-punctured)

[.] BER test:
[..] Testing:
[..] Input BER.......................... 0.007478
[..] Output BER......................... 0.000000
[..] Output FER......................... 0.000000

PASS: conv_test

=================================================
[+] Testing: 3GPP LTE turbo
[.] Specs: (N=2, K=4), Length 6144

[.] BER test:
[..] Testing:
[..] Input BER.......................... 0.007479
[..] Output BER......................... 0.000000
[..] Output FER......................... 0.000000

PASS: turbo_test

Install

$ sudo make install

Benchmark

Various convolutional and turbo decoding tests are available.

$ tests/turbo_test -h
Options:
  -h    This text
  -p    Number of packets (per thread)
  -j    Number of threads for benchmark
  -i    Number of turbo iterations
  -a    Run all tests
  -b    Run benchmark tests
  -n    Run length checks
  -r    Specify SNR in dB (default 8.0 dB)
  -e    Run bit error rate tests
  -c    Test specific code
  -l    List supported codes

Benchmark LTE turbo codes with 8 threads, 4 iterations, and 10000 blocks per thread.

$ tests/turbo_test -b -j 8 -i 4 -p 10000

=================================================
[+] Testing: 3GPP LTE turbo
[.] Specs: (N=2, K=4), Length 6144

[.] Performance benchmark:
[..] Decoding 80000 bursts on 8 thread(s) with 4 iteration(s)
[..] Testing:
[..] Elapsed time....................... 5.925372 secs
[..] Rate............................... 83.043313 Mbps