Change in ...osmocom-bb[master]: trx_toolkit/data_msg.py: implement header version 0x01 coding

fixeria gerrit-no-reply at lists.osmocom.org
Mon Jun 24 03:24:44 UTC 2019


fixeria has uploaded a new patch set (#2). ( https://gerrit.osmocom.org/c/osmocom-bb/+/14579 )

Change subject: trx_toolkit/data_msg.py: implement header version 0x01 coding
......................................................................

trx_toolkit/data_msg.py: implement header version 0x01 coding

The new version mostly adds new fields to the TRX2L1 message:

  +------+-----+-----+-----+-----+--------------------+
  | RSSI | ToA | MTS | C/I | L16 | soft-bits (254..0) |
  +------+-----+-----+-----+-----+--------------------+

  where:

    - MTS (1 octet)  - Modulation and Training Sequence info,
    - C/I (2 octets) - Carrier-to-Interference ratio (big endian),
    - L16 (2 octets) - length of burst (big endian).

In case of L12TRX, the burst bits are now also encoded as L16V:

  +-----+-----+--------------------+
  | PWR | L16 | hard-bits (1 or 0) |
  +-----+-----+--------------------+

== Coding of MTS: Modulation and Training Sequence info

3GPP TS 45.002 version 15.1.0 defines several modulation types,
and a few sets of training sequences for each type. The most
common are GMSK and 8-PSK (which is used in EDGE).

  +-----------------+---------------------------------------+
  | 7 6 5 4 3 2 1 0 | bit numbers (value range)             |
  +-----------------+---------------------------------------+
  | . . . . . X X X | Training Sequence Code (0..7)         |
  +-----------------+---------------------------------------+
  | . X X X X . . . | Modulation, TS set number (see below) |
  +-----------------+---------------------------------------+
  | X . . . . . . . | IDLE / nope frame indication (0 or 1) |
  +-----------------+---------------------------------------+

The bit number 7 (MSB) is set to high when either nothing has been
detected, or during IDLE frames, so we can deliver noise levels,
and avoid clock gaps on the L1 side. Other bits are ignored,
and should be set to low (0) in this case. L16 shall be set to 0x00.

== Coding of modulation and TS set number

GMSK has 4 sets of training sequences (see tables 5.2.3a-d),
while 8-PSK (see tables 5.2.3f-g) and the others have 2 sets.
Access and Synchronization bursts also have several synch.
sequences.

  +-----------------+---------------------------------------+
  | 7 6 5 4 3 2 1 0 | bit numbers (value range)             |
  +-----------------+---------------------------------------+
  | . 0 0 X X . . . | GMSK, 4 TS sets (0..3)                |
  +-----------------+---------------------------------------+
  | . 0 1 0 X . . . | 8-PSK, 2 TS sets (0..1)               |
  +-----------------+---------------------------------------+
  | . 0 1 1 X . . . | AQPSK, 2 TS sets (0..1)               |
  +-----------------+---------------------------------------+
  | . 1 0 0 X . . . | 16QAM, 2 TS sets (0..1)               |
  +-----------------+---------------------------------------+
  | . 1 0 1 X . . . | 32QAM, 2 TS sets (0..1)               |
  +-----------------+---------------------------------------+
  | . 1 1 1 X . . . | RESERVED (0)                          |
  +-----------------+---------------------------------------+

== C/I: Carrier-to-Interference ratio

The C/I value is computed from the training sequence of each burst,
where we can compare the "ideal" training sequence with the actual
training sequence and then express that in dB.

Change-Id: Ie810c5a482d1c908994e8cdd32a2ea641ae7cedd
Related: OS#4006
---
M src/target/trx_toolkit/data_msg.py
1 file changed, 289 insertions(+), 32 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/79/14579/2
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-Change-Id: Ie810c5a482d1c908994e8cdd32a2ea641ae7cedd
Gerrit-Change-Number: 14579
Gerrit-PatchSet: 2
Gerrit-Owner: fixeria <axilirator at gmail.com>
Gerrit-CC: Jenkins Builder
Gerrit-MessageType: newpatchset
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