Status of Traffic channel

Hello, here is some information about the current status of traffic channel support in Layer-1: - first of all its not yet complete and considered "alpha" because there are some stability problems which have to be solved and some further enhancments for a more general approach are needed. - What works: Signalling (FACCH/SACCH) for a Full Rate Traffic channel and voice (Full Rate or Enhanced Full Rate Codec). - TODO: The Layer-1 API has to be extended to allow switching the channel mode (e.g. Signalling only) or the Voice Codec. Also turning the audio path on and off is needed. - TODO: The Rx/Tx TPU Window has been modified to support Rx and Tx operation in the same frame. This always happens for a Traffic Channel but can sometimes also happen for other channels. For those cases its necessary that the Tx TPU Window is set differently. Some sort of state information that Rx is happening in the same frame has to be implemented, this currently only works for traffic channels. If you want to try it out you have to use the "dieter/tch_f" branch for Layer-1 and the Master branch for Layer-23 from Andreas (really great work, Andreas). With this combination you can use it with OpenBSC. Some minor adjustment is needed: The Layer-1 code currently sets the voice Codec to "Full Rate", however OpenBSC expects "Enhanced Full Rate" You either have to modify OpenBSC to set "Full Rate" or change "TCH_FS_MODE" to "TCH_EFR_MODE" in "layer1/prim_rx_nb.c", there is only one line which has to be changed. What you can do now is a MOC/MTC between OsmocomBB and another phone. Sometimes it can happen that the firmware hangs, you have to restart the phone in this case. However if you have a connected call, its working pretty good (one of the test calls was over 20 minutes). Maybe Andreas can give a short introduction how to use Layer-23 for this, I am not sure if there is some information in the Wiki yet. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de