Attention is currently required from: jolly, laforge.
1 comment:
Patchset:
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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