On Mon, Nov 14, 2016 at 5:42 PM, Neels Hofmeyr nhofmeyr@sysmocom.de wrote:
On Mon, Nov 14, 2016 at 02:55:30PM +0000, Mrinal Mishra wrote:
As per the channel configuration defined in the code TCH/F_PDCH is a valid channel configuration and it should work as TCH/F or PDCH channel dynamically. I tested even with TCH/F_TCH/H_PDCH and it works fine only as TCH/H or PDCH it does not get used as TCH/F.
I am glad to hear that TCH/F_TCH/H_PDCH works as TCH/H. The reason why this pchan type is not used as TCH/F is OS#1778 https://osmocom.org/issues/1778
Fixing OS#1778 is not a top priority at the moment. The perspective that TCH/H is more efficiently using the available timeslots than TCH/F and the fact that most MS are capable of TCH/H makes this not very urgent.
The reason why people use TCH/F is because it offers higher quality than TCH/H. E.g. if you're using AMR, you can go only up to 7.95 mode in TCH/H (see https://en.wikipedia.org/wiki/Adaptive_Multi-Rate_audio_codec). So just saying that TCH/H is "more efficient" is not correct. It's more efficient in exchange to some loss in quality.