Feature #1572
Circuit Switched Data (CSD) Support
Status:
New
Priority:
Low
Assignee:
-
Category:
osmo-bts-trx
Target version:
-
Start date:
02/23/2016
Due date:
% Done:
0%
Spec Reference:
Description
Not implemented, but also probably limited interest, except
- GSM-R heavily uses CSD and might be an intresting niche market
- some end-to-end encrypted mobile phones also use CSD
This will need the corresponding support in the PHY, of course.
Checklist
- TS 45.003 coding / interleaving
- RSL CHAN ACT for CT
- RA1'/RA1 rate adaptation from/to 64k
- RFC4040 clear-mode RTP payload
Related issues
History
#1 Updated by laforge 9 months ago
- Checklist item TS 45.003 coding / interleaving added
- Checklist item RSL CHAN ACT for CT added
- Checklist item RA1'/RA1 rate adaptation from/to 64k added
- Checklist item RFC4040 clear-mode RTP payload added
The support in OsmoBTS would entail:
- implementation of the 45.003 coding / interleaving for the TCH/F9.6, TCH/F4.8, TCH/F2.4, ... channel types
- activating the above coding/interleaving based on RSL CHAN ACT for such channels
- performing the RA1'/RA1 rate adaptation function to get from/to 64kbps stream
- packetize 64k stream as raw "CLEARMODE/8000" RTP as per RFC4040; 160 bytes per RTP packet; RTP payload type 120
- 3GPP TS 48.004 E1/T1 based L1
- 3GPP TS 48.020 Rate Adaptation on BSS-MSC interface (RA1)
- 3GPP TS 48.103 User plane transport / Section 5.6
- 3GPP TS 44.021 RA1' adaptation function on radio interface
- 3GPP TS 24.022 RLP for CS bearer and teleservices
- 3GPP TS 43.010 PLMN connection types
- ITU-T V.110 RA0 for async->sync
The coding/interleaving part has been started in the laforge/csd branch of libosmocore.git
#3 Updated by laforge 9 months ago
- Related to Feature #4393: Circuit Switched Data (CSD) Support added
#4 Updated by laforge 9 months ago
- Related to Feature #4394: Circuit Switched Data (CSD) Support added
#5 Updated by laforge 9 months ago
- Related to Feature #4395: Circuit Switched Data (CSD) Support added
#6 Updated by laforge 9 months ago
- Category set to osmo-bts-trx
Some more notes:
- Racal 6103 supports termination of data + fax CSD calls (external PC can be connected on RS232). This could be used to establish air-interface (burst level) captures using burst_ind. That in turn could generate test data for the 45.003 de-interleave/decoder part.
- support in OsmoBTS would be restricted to osmo-bts-trx, as to our current knowledge none of the proprietary PHYs (osmo-bts-{sysmo,lc15,oc2g,octphy} support CSD channel coding
#7 Updated by laforge 9 months ago
- Related to Feature #4396: Circuit Switched Data (CSD) Support added
