Extended (11-bit) RACH support in OsmoTRX
OsmoTRX is currently only correlating with one of the three RACH sync sequences indicated in TS 05.02 5.2.7. We need to define TS1+TS2 as well as correlated against thosee during RACH detection
const BitVector GSM::gRACHSynchSequence("01001011011111111001100110101010001111000"); +const BitVector GSM::gRACHSynchSequenceTS1("01010100111110001000011000101111001001101"); /* EGPRS with 8PSK in uplink */ +const BitVector GSM::gRACHSynchSequenceTS2("11101111001001110101011000001101101110111"); /* EGPRS without 8PSK in uplink */
- sigProcLib: introduce both TS1 and TS2 RACH synch. sequences
- sigProcLib: add a CorrType for extended (11-bit) RACH
- Distinguish handover RACH
- Extend TRXC interface
sigProcLib: introduce both TS1 and TS2 RACH synch. sequences
According to 3GPP TS 05.02, section 5.2.7, there are three
synch. sequences for Access Bursts:
- TS0: GSM, GMSK (default),
- TS1: EGPRS, 8-PSK,
- TS2: EGPRS, GMSK.
Let's prepare everythyng to be able to detect all TS0-3 synch.
sequences, but keep detection of both TS1 and TS2 disabled
until the corresponding VTY option is introduced.
sigProcLib: add a CorrType for extended (11-bit) RACH
This is a preparatory change that enables a possibility to choose
the amount of synch. sequences to be used for Access Burst (RACH)
detection. The VTY flag will be introduced in further changes.
There are two correlation types now:
- RACH (default) - TS0 only;
- EXT_RACH - all TS0, TS1, and TS2 together.
VTY: add extended (11-bit) RACH detection toggle
Since I838c21db29c54f1924dd478c2b34b46b70aab2cd we have both TS1
and TS2 synch. sequences, in addition to "default" TS0. Let's
finally introduce the VTY configuration parameter, that can
be used to toggle optional detection of both TS1 and TS2.
Note: we keep this optional because of potentially bad impact on
performance. There's no point in paying the performance penalty
unless upper levels (BTS, PCU) actually make use of it.
#4 Updated by fixeria almost 3 years ago
- Tracker changed from Bug to Feature
- Subject changed from 11bit RACH support in OsmoTRX to Extended (11-bit) RACH support in OsmoTRX
- Status changed from New to Feedback
- % Done changed from 0 to 80
Initial work has already been done, please see:
https://gerrit.osmocom.org/11390/ sigProcLib: introduce both TS1 and TS2 RACH synch. sequences
https://gerrit.osmocom.org/11422/ sigProcLib: add a CorrType for extended (11-bit) RACH
https://gerrit.osmocom.org/11423/ VTY: add extended (11-bit) RACH detection toggle
#9 Updated by fixeria over 2 years ago
- Checklist item sigProcLib: introduce both TS1 and TS2 RACH synch. sequences added
- Checklist item sigProcLib: add a CorrType for extended (11-bit) RACH added
- Checklist item Distinguish handover RACH added
- Checklist item Extend TRXC interface added
- Status changed from Feedback to Stalled
- % Done changed from 80 to 90
Since I1aee998d83b06692d76a83f79748f9129a2547e8 is merged, OsmoTRX can now be instructed to enable the both TS1 and TS2 sequences. There is still some room for (performance) improvements though. As suggested by Harald, we can extend the TRXC (TRX Control) interface in order to be able to indicate whether to enable TS1/TS2 detection on a given timeslot.