Feature #4941

VAMOS support in OsmoBTS

Added by laforge 4 months ago. Updated 22 days ago.

In Progress
Target version:
Start date:
Due date:
% Done:


Spec Reference:


This ticket should document what needs to be done in terms of supporting VAMOS from OsmoBTS, and to track its status via check-lists and possibly sub-issues.

Our implementation will be focusing on osmo-bts-trx as none of the "proprietary PHY" we support implement any VAMOS support.

This likely includes (at least)
  1. Indication of [which level of] VAMOS support the BTS has via OML attributes to BSC
  2. Implementation of "shadow TRX" concept in data structures
  3. Implementation of VAMOS related RSL extensions on Abis
  4. Implementation of a new TRXDv2 protocol from/to the TRX
  5. VAMOS-aware uplink + downlink power control
  6. generation of one set of downlink symbols from the real + shadow timeslot/lchan

The corresponding BSC related work is tracked in #4940

Related issues

Related to OsmoBSC - Feature #4940: VAMOS support in OsmoBSCNew01/12/2021

Related to Cellular Network Infrastructure - Feature #4006: TRX protocol: wind of changeIn Progress05/17/2019

Blocked by Cellular Network Infrastructure - Bug #5112: osmo-gsm-manuals: build verification is brokenResolved04/10/2021


#1 Updated by laforge 4 months ago

#2 Updated by Hoernchen 4 months ago

According to chapter 4 random pairings with scpir=0 should be fine for the time being.

#3 Updated by fixeria 4 months ago

  • Status changed from New to In Progress

#4 Updated by fixeria 3 months ago

#5 Updated by fixeria about 1 month ago

  • Blocked by Bug #5112: osmo-gsm-manuals: build verification is broken added

#6 Updated by fixeria 22 days ago

  • % Done changed from 0 to 20

I've submitted a bunch of TRXDv2 related changes to Gerrit: osmo-bts-trx: cosmetic: TRXD 'header version' -> 'PDU version' osmo-bts-trx: remove outdated TRXD protocol documentation osmo-bts-trx: cosmetic: use '#pragma once' in trx_if.h osmo-bts-trx: reduce and share TRXC message buffer size osmo-bts-trx: move TRXD message length to trx_if.h osmo-bts-trx: 'burst type' is actually modulation type osmo-bts-trx: move MTS parser into trx_data_parse_mts() osmo-bts-trx: discard TRXD PDUs with unexpected version osmo-bts-trx: move TDMA frame number check to trx_data_read_cb() osmo-bts-trx: cosmetic: get rid of TRX_CHDR_LEN macro osmo-bts-trx: refactor handling of version specific TRXD parts osmo-bts-trx: implement TRXDv2 protocol support

together with other L1SAP/RSL related changes (all of them have been merged): protocol/gsm_08_58.h: add RSL_CMOD_SP_{GSM4,GSM5,GSM6} protocol/gsm_08_58.h: add more 'Channel rate and type' values protocol/gsm_08_58.h: add asymmetric CSD data rates l1sap: fix incorrect pointer cast in l1sap_chan_act() rsl: rename, fix and refactor lchan_tchmode_from_cmode() rsl: add missing Channel Mode values to rsl_handle_chan_mod_ie()

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