During the handover the MS needs to release the existing dedicated
channel(s), establish the new one(s) as indicated by the network,
and then, depending on the synchronisation state, send one or more
HANDOVER ACCESS messages carried by Access Bursts.
In order to implement this, trxcon needs to be able to transmit
Access Bursts on any TDMA timeslot regardless of the logical
channel type and the associated handler, i.e. != TRXC_RACH.
The controlling side on L1CTL (layer23 or TTCN-3) needs to send
one or more L1CTL_RACH_REQ message(s) with properly populated
UL info header. Otherwise a regular RACH on TS0 is assumed.
Change-Id: Ia967820a536c99966ba2c60b63d2ea9edb093f46
Both PRIM_IS_RACH() and PRIM_IS_EXT_RACH() macros to be used for
handover RACH detection in the follow up changes, thus we need
have them widely available. Let's also give them better names:
PRIM_IS_EXT_RACH -> PRIM_IS_RACH11
PRIM_IS_RACH -> PRIM_IS_RACH8
and introduce a new generic one for checking whether a given
primitive is RACH in general (either 8-bit or 11-bit) or not.
Change-Id: Ibc39c57fda000647be1829786f6423dcf3f435cd
This would allow to abstract both L1CTL and TRX interfaces
from each other in the upcoming refactoring.
Change-Id: I74a23c73b03bad822272b9cfe76c2501666912b7
According to 3GPP TS 05.03, section 5.3, two coding schemes are
specified for access bursts: one for regular 8-bit bursts,
another - for extended 11-bit packet access bursts.
According to 3GPP TS 05.02, section 5.2.7, there are two
additional training (synchronization) sequences for RACH
bursts: TS1 & TS2. By default, TS0 synch. sequence is used,
unless explicitly stated otherwise (see 3GPP TS 04.60).
According to 3GPP TS 04.60, section 11.2.5a, the EGPRS capability
can be indicated by the MS using an alternative training sequence
(i.e. TS1 or TS2) and the 11-bit RACH coding scheme.
Change-Id: I36fd20cd5502ce33c52f644ee4c22abb83350df8
We used to trust (and still doing this) the messages coming from
L1CTL interface too much, and not to check the primitive length
before passing the payload to the libosmocoding API. As was
discovered and described in OS#3415, sending a L1CTL message
(either DATA_REQ, or TRAFFIC_REQ) with an incorrect length
(lower than expected) may cause heap overflow.
Let's explicitly check a primitive before encoding, and drop it
if its length doesn't match the expected value(s).
Change-Id: I258ee9f6d0124b183b1db23a73f1e523fcea89a8
Fixes: OS#3415
Currently Access Burst generated by trxcon
has 8 zero bits at the beginning. According to
the 3GPP 05.02 specification (Chapter 5.2.7
Access burst) custom 8-bit extended tail bits
sequence should be used:
(BN0, BN1, BN2 ... BN7) = (0,0,1,1,1,0,1,0)
After this fix trxcon sets correct 8-bit
sequence at the front of Access burst.
Change-Id: I1f624e783de6c585d2e292965c9e5810b0a4f27d
Having a possibility to preprocess UL burst before sending to
transceiver is required for the further ciphering support
integration and probably some other tasks.
Change-Id: Ia6eead5d4f51d7c0bf277b9d5ebb0a74676df567
Previously, each lchan handler used to obtain and delete primitives
from a timeslot's tranmit queue itself. This approach entails many
potential problems and bugs:
- The lchan handlers shall not do that by definition, they
should encode and decode frames according to GSM 05.03.
- In some cases (e.g. TCH), a single transmit queue may contain
primitives of different types (e.g. TCH, FACCH and SACCH). At
the same time, the lchan handlers don't care and don't even
know about each other. So, this could cause an unexpected
behaviour in some cases.
This change separates all primitive management routines,
providing a new API for obtaining and dropping them.
"Write programs that do one thing and do it well."
Change-Id: I29503ece51903784bc53541015285234471c8d15
Since the 32e5641d, the gsm0503_rach_encode() is deprecated, and
the library provides new API with extended (11-bit) RACH support.
Change-Id: I1955fe46eebd173d6eddd1d47ee9f7318b9b4e2d
It's better to pass a trx_lchan_state instance directly from
caller to lchan handler instead of passing trx_lchan_type. This
way a handler wouldn't need to find lchan itself.
Change-Id: I47a40542b03ab31da12b0abb1c263c83662ff018
It would be better to have xCCH, SCH and RACH burst handlers
in separate files, because as much code we add to a single
file, as harder it becomes to read and understand one.
Change-Id: I456a60e68b32b792e63dd03ae97159dc101fd4bf
Vadim Yanitskiy