Feature #4196
openCC Setup, Call Confirmed: decode and use the Supported Codec List IE
Added by neels over 4 years ago. Updated over 4 years ago.
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Description
In the CC Setup / CC Call Confirmed messages, there is a Supported Codec List IE besides the Bearer Capabilities.
So far we only decode and handle the information from the Bearer Capabilities,
but instead or in addition we may want to also look at this Supported Codec List IE.
Updated by neels over 4 years ago
An example dissection of a CC Setup:
Note that further above, there is a Bearer Capabilities listing of codecs, while further below there also is the Supported Codec List, with separate information for UMTS and GSM.
3GPP TS 24.008 says that "This information element shall be included for speech calls, if the mobile station supports UMTS radio access." (I interpret this so that UMTS doesn't imply 3G, but means R99 and is also used on 2G).
The Supported Codecs are only present in the MO CC Setup (not in MT, where the CN sends the CC Setup), but is also contained in the CC Call Confirmed message (which in MT the MS sends to the CN).
GSM A-I/F DTAP - Setup Protocol Discriminator: Call Control; call related SS messages (3) .... 0011 = Protocol discriminator: Call Control; call related SS messages (0x3) 0... .... = TI flag: allocated by sender .000 .... = TIO: 0 10.. .... = Sequence number: 2 ..00 0101 = DTAP Call Control Message Type: Setup (0x05) Bearer Capability 1 - (MS supports at least full rate speech version 1 and half rate speech version 1. MS has a greater preference for full rate speech version 1 than for half rate speech version 1) Element ID: 0x04 Length: 6 Octet 3 0... .... = Extension: Extended .11. .... = Radio channel requirement: MS supports at least full rate speech version 1 and half rate speech version 1. MS has a greater preference for full rate speech version 1 than for half rate speech version 1 ...0 .... = Coding standard: GSM standardized coding .... 0... = Transfer mode: circuit .... .000 = Information transfer capability: Speech (0x0) Octets 3a - Speech Versions 0... .... = Extension: Extended .0.. .... = Coding: octet used for extension of information transfer capability ..00 .... = Spare bit(s): 0 .... 0100 = Speech version indication: GSM full rate speech version 3(FR AMR) (0x4) 0... .... = Extension: Extended .0.. .... = Coding: octet used for extension of information transfer capability ..00 .... = Spare bit(s): 0 .... 0010 = Speech version indication: GSM full rate speech version 2(GSM EFR) (0x2) 0... .... = Extension: Extended .0.. .... = Coding: octet used for extension of information transfer capability ..00 .... = Spare bit(s): 0 .... 0000 = Speech version indication: GSM full rate speech version 1(GSM FR) (0x0) 0... .... = Extension: Extended .0.. .... = Coding: octet used for extension of information transfer capability ..00 .... = Spare bit(s): 0 .... 0101 = Speech version indication: GSM half rate speech version 3(HR AMR) (0x5) 1... .... = Extension: No Extension .0.. .... = Coding: octet used for extension of information transfer capability ..00 .... = Spare bit(s): 0 .... 0001 = Speech version indication: GSM half rate speech version 1(GSM HR) (0x1) Called Party BCD Number - (2002) Element ID: 0x5e Length: 3 1... .... = Extension: No Extension .000 .... = Type of number: unknown (0x0) .... 0001 = Numbering plan identification: ISDN/Telephony Numbering (ITU-T Rec. E.164 / ITU-T Rec. E.163) (0x1) Called Party BCD Number: 2002 Call Control Capabilities Element ID: 0x15 Length: 2 0000 .... = Maximum number of supported bearers: 1 .... 0... = MCAT: The mobile station does not support Multimedia CAT .... .0.. = ENICM: The mobile station does not support the Enhanced Network-initiated In-Call Modification procedure .... ..0. = Prolonged Clearing Procedure: Not supported .... ...1 = DTMF: the mobile station supports DTMF as specified in subclause 5.5.7 of TS 24.008 0000 .... = Spare bit(s): 0 .... 0000 = Maximum number of speech bearers: 0 Supported Codec List Element ID: 0x40 Length: 8 System Identification (SysID): UMTS (0x04) Bitmap Length: 2 Codec Bitmap for SysID 1 0... .... = TDMA EFR: False .1.. .... = UMTS AMR 2: True ..1. .... = UMTS AMR: True ...0 .... = HR AMR: False .... 0... = FR AMR: False .... .0.. = GSM EFR: False .... ..0. = GSM HR: False .... ...0 = GSM FR: False 00.. .... = Spare bit(s): 0 ..0. .... = OHR AMR-WB: False ...0 .... = OFR AMR-WB: False .... 0... = OHR AMR: False .... .1.. = UMTS AMR-WB: True .... ..0. = FR AMR-WB: False .... ...0 = PDC EFR: False System Identification (SysID): GSM (0x00) Bitmap Length: 2 Codec Bitmap for SysID 2 0... .... = TDMA EFR: False .0.. .... = UMTS AMR 2: False ..0. .... = UMTS AMR: False ...1 .... = HR AMR: True .... 1... = FR AMR: True .... .1.. = GSM EFR: True .... ..1. = GSM HR: True .... ...1 = GSM FR: True 00.. .... = Spare bit(s): 0 ..0. .... = OHR AMR-WB: False ...0 .... = OFR AMR-WB: False .... 0... = OHR AMR: False .... .0.. = UMTS AMR-WB: False .... ..0. = FR AMR-WB: False .... ...0 = PDC EFR: False
Updated by neels over 4 years ago
- Subject changed from CC Setup: decode and use the Supported Codec List IE to CC Setup, Call Confirmed: decode and use the Supported Codec List IE
- Description updated (diff)
Updated by neels over 4 years ago
Related:
24.008 5.2.1 Mobile originating call establishment:
For speech calls the mobile station shall indicate all codecs that it supports for UTRAN in the Supported Codec List
information element. Codecs for GERAN shall be indicated in the Bearer Capability information element, if this
information element is included. Additionally, if the mobile station supports codecs for GERAN and UTRAN, it shall
indicate the codecs for GERAN also in the Supported Codec List information element.
24.008 5.2.2.3.2 Receipt of CALL CONFIRMED and ALERTING by the network:
For speech calls, if the CALL CONFIRMED message contains a Supported Codec List information element, the
network shall use this list to select the codec for UTRAN. If no Supported Codec List information element is received,
then for UTRAN the network shall select the default UMTS speech codec according to subclause 5.2.1.11.
Codecs for GERAN shall be selected from the codecs indicated in the Supported Codec List information element or in
the Bearer Capability information element. If neither a Supported Codec List information element nor a Bearer
Capability information element is received, then for GERAN the network shall select GSM full rate speech version 1.