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Hello Jenkins Builder, fixeria, laforge, pespin,

I'd like you to reexamine a change. Please visit

https://gerrit.osmocom.org/c/libosmo-abis/+/38292?usp=email

to look at the new patch set (#5).

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Change subject: libosmotrau: implement RAA' encoder function ......................................................................

libosmotrau: implement RAA' encoder function

RAA' is the rate adaption function specific to 14.4 kbit/s CSD services. It is defined in 3GPP TS 48.020 chapter 11, and consists of transforming each user data frame of 290 bits (as it would appear at the radio channel coder interface) into a special A-TRAU frame. 64 kbit/s streams consisting of these A-TRAU frames are meant to traverse the call switching network from one mobile call leg to the other, or from a mobile call leg to an IWF.

RAA' transform involves rather bewildering manipulation of payload bit content, done to prevent any possibility of false A-TRAU frame alignment in octet-oriented (no frame boundaries) 64 kbit/s transport. The complexity is such that unit tests are essential, especially unit tests that cross-check our software implementation against those made by others.

Fortunately this RAA' function is included in traditional T1/E1 TRAUs, those that support CSD in 14.4 kbit/s mode and implement it according to the specs. Nokia TCSM2 in Themyscira lab includes the necessary support, and the present patch includes a unit test that verifies perfect agreement between our software implementation of RAA' encoder and the historical hw implementation in the old Nokia TRAU.

Related: OS#6167 Change-Id: I11fc1529f5be88fa778c7e05cb11eef58a389d40 --- M .gitignore M include/Makefile.am A include/osmocom/trau/csd_raa_prime.h M src/Makefile.am A src/trau/raa_prime_encode.c M tests/Makefile.am A tests/raa_prime/README.test-data A tests/raa_prime/d144-ul-input.asc A tests/raa_prime/nokia-tcsm2-atrau.hex A tests/raa_prime/test_enc.c M tests/testsuite.at 11 files changed, 396 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/libosmo-abis refs/changes/92/38292/5