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comparison doc/Calypso-TCH-downlink @ 182:2254fa16ec5f

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doc/Calypso-TCH-downlink: update for fc-host-tools-r18 release
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 02 Jan 2023 23:05:38 +0000
parents 62c0359ff2a8
children 03b0702f4463
comparison
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181:3a0ee08a3b9d 182:2254fa16ec5f
5 repository. There is a mechanism to capture the stream of received traffic 5 repository. There is a mechanism to capture the stream of received traffic
6 frames on TCH DL, and there is another mechanism by which an externally supplied 6 frames on TCH DL, and there is another mechanism by which an externally supplied
7 stream can be "played" into TCH UL. 7 stream can be "played" into TCH UL.
8 8
9 I (Mother Mychaela) previously played with this functionality back in 2016, and 9 I (Mother Mychaela) previously played with this functionality back in 2016, and
10 it's been mostly shelved since then. This functionality is now getting renewed 10 it's been mostly shelved since then. This functionality became interesting
11 attention in late 2022: now that we have a proper set of codec libraries (the 11 once again in late 2022: now that we have a proper set of codec libraries (the
12 present package) and a proper understanding of Rx DTX handling requirements, we 12 present package) and a proper understanding of Rx DTX handling requirements, we
13 can take another shot at decoding TCH downlink captures taken from Calypso GSM 13 can take another shot at decoding TCH downlink captures taken from Calypso GSM
14 MS. 14 MS.
15 15
16 The overall functionality is described in the TCH-tap-modes article in 16 The overall functionality is described in the TCH-tap-modes article in
17 freecalypso-docs; the mechanism for capturing TCH DL bits from Calypso DSP is 17 freecalypso-docs; the mechanism for capturing TCH DL bits from Calypso DSP is
18 split between FreeCalypso GSM MS firmware (added to FC Tourmaline as of 18 split between FreeCalypso GSM MS firmware (added to FC Tourmaline as of
19 2022-12-23) and the fc-shell utility in the FC host tools package - the updated 19 2022-12-13) and the fc-shell utility in the FC host tools package, updated as
20 version (required for use with current Tourmaline fw) will be released as part 20 of fc-host-tools-r18 to support the new FreeCalypso fw. There is also a set of
21 of fc-host-tools-r18. There is also a set of utilities included in the present 21 utilities included in the present GSM codec libraries & utilities package for
22 GSM codec libraries & utilities package for parsing and decoding these Calypso 22 parsing and decoding these Calypso TCH DL captures; the present document
23 TCH DL captures; the present document describes these utilities. 23 describes these utilities.
24 24
25 As explained in the TCH-tap-modes article in freecalypso-docs, the mechanism 25 As explained in the TCH-tap-modes article in freecalypso-docs, the mechanism
26 for capturing TCH DL is currently implemented for TCH/FS, TCH/HS and TCH/EFS, 26 for capturing TCH DL is currently implemented for TCH/FS, TCH/HS and TCH/EFS,
27 corresponding to FR1, HR1 and EFR codecs. However, further parsing and decoding 27 corresponding to FR1, HR1 and EFR codecs. However, further parsing and decoding
28 support has only been implemented for FR1 and EFR codecs in the present package, 28 support has only been implemented for FR1 and EFR codecs in the present package,