Attention is currently required from: jolly, laforge.

fixeria has posted comments on this change. ( 
https://gerrit.osmocom.org/c/osmocom-bb/+/34913?usp=email )

Change subject: mobile: cosmetic: rename TCH_IOFF_RTP to TCH_IOFF_OSMO
......................................................................


Patch Set 2:

(1 comment)

Patchset:

PS2:
> Do we ever communicate CSD data in a non-RTP (and hence non-rate-adapted) 
> fashion?

On the L1CTL interface - yes. The `TRAFFIC.ind` messages currently carry packed 
bits generated by the convolutional decoder, and similarly the `TRAFFIC.req` 
messages carry packed bits to be fed to the convolutional encoder. In the case 
of TCH/F9.6 it's `4 * 60 == 240 bits / 8 == 30 bytes`.

The difference between 'osmo' and 'ti' is the endianness: Calypso firmware 
emits frames with bytes swapped in words (`\x01\x02\x03\x04` becomes 
`\x02\x01\x04\x03`). While we could modify the firmware and make it emit frames 
in big endian (like trxcon does), this would break regular voice calls because 
the TI format block in libosmogapk expects the little endian ordering.

For now I don't see a need for the L1 PHY (be it Calypso firmware or 
trxcon/virtphy) to perform the rate adaptation to 64 kbit/s like the BSS does. 
This would impose even higher bandwidth requirements on the serial interface 
between the host and the firmware (4 x times for TCH/F9.6). We can always do 
this on the host side, if needed, right?



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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-Change-Id: I780d0a9fc20244ffa34307fb3d00f3848b6dcc76
Gerrit-Change-Number: 34913
Gerrit-PatchSet: 2
Gerrit-Owner: fixeria <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: jolly <[email protected]>
Gerrit-CC: laforge <[email protected]>
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Gerrit-Attention: laforge <[email protected]>
Gerrit-Comment-Date: Mon, 30 Oct 2023 09:15:20 +0000
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