Changes

csd_v110: add CSD_V110_NUM_BITS macro

Change-Id: Iabd2ee5ea9d580e0a6f5c93d681f6be67d1949c5

csd_v110: clarify field names in csd_v110_lchan_desc[]

A radio-interface block in GSM carries several modified 36-bit or
60-bit V.110 frames.  Let's rename the fields to avoid confusion.

Change-Id: If97787a64e30ff9b39c26749ba32aed09d3d7983

csd_v110: clarify lchan description for TCH/F14.4

According to 3GPP TS 44.021, section 10.3.2, a radio-interface data
block for a TCH/F14.4 channel consists of eight 36-bit data frames
and two M-bits (290 bits total).  Let's fix our definition.

Change-Id: I4f11eda98420587efa339484b62f46bf19f78809
Related: OS#6167

csd_v110: handle TCH/F14.4

Thanks to the work done by Mychaela (see the related Change-IDs), we
can finally implement handling of TCH/F14.4 (both T and NT modes) for
osmo-bts-trx and osmo-bts-virtual.

This channel mode is special in a way that it employs a different
rate adaptation function RAA' (defined in 3GPP TS 48.020 chapter 11),
which converts between between 290-bit blocks used on Um and Abis-E1
interfaces (E-TRAU frames on the latter) and A-TRAU frames spoken
over the A interface.

The result of function RAA' in the Uplink direction is 320 bits,
which is equal to 4 x 80-bit V.110 frames, but actually carrying
8 x 36-bit packed frames.  These 320 bits are then fed to the RA2
function, like we do for other CSD channel modes.

Change-Id: I3c3bef0bd2f72b8381597b5699e2060165b702a0
Depends: libosmo-abis.git I11fc1529f5be88fa778c7e05cb11eef58a389d40
Depends: libosmo-abis.git I1347a25ce97d5022502ee9112caded66315b09a4
Related: OS#6167