diff options
author | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2021-02-20 00:04:22 +0100 |
---|---|---|
committer | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2021-04-08 03:20:39 +0200 |
commit | 7c3a566b520af237581a84909fc65e1a15d6bdb2 (patch) | |
tree | b1646300a28ebb8f6c613a556bb535ad3efd16b6 | |
parent | 33f456dda34dcf833828a3991fea36ff8ed89206 (diff) |
trx_toolkit: define TRXDv0/v1 PDUs using declarative codec
-rw-r--r-- | src/target/trx_toolkit/trxd_proto.py | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/src/target/trx_toolkit/trxd_proto.py b/src/target/trx_toolkit/trxd_proto.py new file mode 100644 index 00000000..aef3351d --- /dev/null +++ b/src/target/trx_toolkit/trxd_proto.py @@ -0,0 +1,120 @@ +# -*- coding: utf-8 -*- + +''' +TRXD PDU definitions based on declarative codec. +''' + +# TRX Toolkit +# +# (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> +# Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de> +# +# All Rights Reserved +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +import codec + +class Header(codec.BitFieldSet): + ''' Header constructor for TRXD PDUs. ''' + + def __init__(self, ver: int): + codec.BitFieldSet.__init__(self, len=1, set=( + codec.BitField('ver', bl=4, val=ver), + codec.BitField.Pad(bl=1), # RFU + codec.BitField('tn', bl=3), + )) + +class MTS(codec.BitFieldSet): + ''' Modulation and Training Sequence. ''' + + DEF_LEN = 1 + STRUCT = ( + codec.BitField('nope', bl=1), + codec.BitField('mod', bl=4), + codec.BitField('tsc', bl=3), + ) + + @staticmethod + def get_burst_len(mod: int) -> int: + ''' Get burst length by modulation type. ''' + + GMSK_BURST_LEN = 148 + + if (mod >> 2) in (0b00, 0b11): # GMSK or AQPSK + return 1 * GMSK_BURST_LEN + elif (mod >> 1) == 0b010: # 8-PSK + return 3 * GMSK_BURST_LEN + elif (mod >> 1) == 0b100: # 16QAM + return 4 * GMSK_BURST_LEN + elif (mod >> 1) == 0b101: # 32QAM + return 5 * GMSK_BURST_LEN + elif mod == 0b0110: # GMSK (Access Burst) + return 1 * GMSK_BURST_LEN + raise ValueError('Unknown modulation type') + +class BurstBits(codec.Buf): + ''' Soft-/hard-bits with variable length. ''' + + def __init__(self, name: str, *args, **kw): + codec.Buf.__init__(self, name, *args, **kw) + + # This field has a variable length that depends on moduletion type + self.get_len = lambda v, _: MTS.get_burst_len(v['mod']) + # This field is not present in NOPE / IDLE indications + self.get_pres = lambda v: not v['nope'] + + +class PDUv0Rx(codec.Envelope): + STRUCT = ( + Header(ver=0), + codec.Uint32BE('fn'), + codec.Uint('rssi', mult=-1), + codec.Int16BE('toa256'), + codec.Buf('soft-bits'), + codec.Buf('pad'), # Optional + ) + + def __init__(self, *args, **kw): + codec.Envelope.__init__(self, *args, **kw) + + # Field 'soft-bits' is either 148 (GMSK) or 444 (8-PSK) octets long + self.STRUCT[-2].get_len = lambda _, data: 444 if len(data) > 148 else 148 + +class PDUv0Tx(codec.Envelope): + STRUCT = ( + Header(ver=0), + codec.Uint32BE('fn'), + codec.Uint('pwr'), + codec.Buf('hard-bits'), + ) + + +class PDUv1Rx(codec.Envelope): + STRUCT = ( + Header(ver=1), + codec.Uint32BE('fn'), + codec.Uint('rssi', mult=-1), + codec.Int16BE('toa256'), + MTS(), + codec.Int16BE('cir'), + BurstBits('soft-bits'), + ) + +class PDUv1Tx(PDUv0Tx): + # Same structure as PDUv0Tx, only the version is different + def __init__(self, *args, **kw): + PDUv0Tx.__init__(self, *args, **kw) + self.STRUCT[0]._fields[0].val = 1 |