gr-gsm/python/trx/radio_if.py

329 lines
8.7 KiB
Python

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
# GR-GSM based transceiver
# Follow graph implementation
#
# (C) 2016-2019 by Vadim Yanitskiy <axilirator@gmail.com>
# (C) 2017 by Piotr Krysik <ptrkrysik@gmail.com>
#
# 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 pmt
import time
import grgsm
import random
from math import pi
from gnuradio import eng_notation
from gnuradio import digital
from gnuradio import blocks
from gnuradio import uhd
from gnuradio import gr
from gnuradio import filter
from gnuradio.filter import firdes
from dict_toggle_sign import dict_toggle_sign
class RadioInterface(gr.top_block):
# PHY specific variables
rx_freq = None
tx_freq = None
osr = 4
# GSM timings (in microseconds [uS])
# One timeslot duration is 576.9 μs = 15/26 ms,
# or 156.25 symbol periods (a symbol period is 48/13 μs)
GSM_SYM_PERIOD_uS = 48.0 / 13.0
GSM_TS_PERIOD_uS = GSM_SYM_PERIOD_uS * 156.25
GSM_UL_DL_SHIFT_uS = -(GSM_TS_PERIOD_uS * 3)
GSM_SYM_RATE = (1.0 / GSM_SYM_PERIOD_uS) * 1e6
SAMPLE_RATE = GSM_SYM_RATE * osr
# FIXME: shall be measured (automatically?) for
# particular device and particular clock rate.
# The current value is measured for USRP B2X0 at 26e6.
delay_correction = (285.616 + 2 * GSM_SYM_PERIOD_uS) * 1e-6
# Dummy freq. value that is used during initialization
# basically, the DL freq. of ARFCN 0
DUMMY_FREQ = 935e6
def __init__(self, phy_args, phy_sample_rate,
phy_rx_gain, phy_tx_gain, phy_ppm,
phy_rx_antenna, phy_tx_antenna,
phy_freq_offset, trx_bind_addr,
trx_remote_addr, trx_base_port):
print("[i] Init Radio interface (L:%s:%u <-> R:%s:%u)"
% (trx_bind_addr, trx_base_port + 2,
trx_remote_addr, trx_base_port + 102))
# PHY specific variables
self.sample_rate = phy_sample_rate
self.rx_gain = phy_rx_gain
self.tx_gain = phy_tx_gain
self.ppm = phy_ppm
self.freq_offset = phy_freq_offset
gr.top_block.__init__(self, "GR-GSM TRX")
# TRX Burst Interface
self.trx_burst_if = grgsm.trx_burst_if(
trx_bind_addr, trx_remote_addr,
str(trx_base_port))
# RX path definition
self.phy_src = uhd.usrp_source(phy_args,
uhd.stream_args(cpu_format="fc32",
channels=range(1)))
self.phy_src.set_clock_rate(26e6, uhd.ALL_MBOARDS)
self.phy_src.set_antenna(phy_rx_antenna, 0)
self.phy_src.set_samp_rate(phy_sample_rate)
self.phy_src.set_bandwidth(650e3, 0)
self.phy_src.set_gain(phy_rx_gain)
self.msg_to_tag_src = grgsm.msg_to_tag()
self.rotator_src = grgsm.controlled_rotator_cc(0.0)
self.lpf = filter.fir_filter_ccf(1, firdes.low_pass(
1, phy_sample_rate, 125e3, 5e3, firdes.WIN_HAMMING, 6.76))
self.gsm_receiver = grgsm.receiver(self.osr, ([0]), ([]))
self.ts_filter = grgsm.burst_timeslot_filter(0)
self.ts_filter.set_policy(grgsm.FILTER_POLICY_DROP_ALL)
# Connections
self.connect(
(self.phy_src, 0),
(self.msg_to_tag_src, 0))
self.connect(
(self.msg_to_tag_src, 0),
(self.rotator_src, 0))
self.connect(
(self.rotator_src, 0),
(self.lpf, 0))
self.connect(
(self.lpf, 0),
(self.gsm_receiver, 0))
self.msg_connect(
(self.gsm_receiver, 'C0'),
(self.ts_filter, 'in'))
self.msg_connect(
(self.ts_filter, 'out'),
(self.trx_burst_if, 'bursts'))
# TX Path Definition
self.phy_sink = uhd.usrp_sink(phy_args,
uhd.stream_args(cpu_format="fc32",
channels=range(1)), "packet_len")
self.phy_sink.set_clock_rate(26e6, uhd.ALL_MBOARDS)
self.phy_sink.set_antenna(phy_tx_antenna, 0)
self.phy_sink.set_samp_rate(phy_sample_rate)
self.phy_sink.set_gain(self.tx_gain)
self.tx_time_setter = grgsm.txtime_setter(
0xffffffff, 0, 0, 0, 0, 0,
self.delay_correction + self.GSM_UL_DL_SHIFT_uS * 1e-6)
self.tx_burst_proc = grgsm.preprocess_tx_burst()
self.pdu_to_tagged_stream = blocks.pdu_to_tagged_stream(
blocks.byte_t, 'packet_len')
self.gmsk_mod = grgsm.gsm_gmsk_mod(
BT = 0.3, pulse_duration = 4, sps = self.osr)
self.burst_shaper = digital.burst_shaper_cc(
(firdes.window(firdes.WIN_HANN, 16, 0)),
0, 20, False, "packet_len")
self.msg_to_tag_sink = grgsm.msg_to_tag()
self.rotator_sink = grgsm.controlled_rotator_cc(0.0)
# Connections
self.msg_connect(
(self.trx_burst_if, 'bursts'),
(self.tx_time_setter, 'bursts_in'))
self.msg_connect(
(self.tx_time_setter, 'bursts_out'),
(self.tx_burst_proc, 'bursts_in'))
self.msg_connect(
(self.tx_burst_proc, 'bursts_out'),
(self.pdu_to_tagged_stream, 'pdus'))
self.connect(
(self.pdu_to_tagged_stream, 0),
(self.gmsk_mod, 0))
self.connect(
(self.gmsk_mod, 0),
(self.burst_shaper, 0))
self.connect(
(self.burst_shaper, 0),
(self.msg_to_tag_sink, 0))
self.connect(
(self.msg_to_tag_sink, 0),
(self.rotator_sink, 0))
self.connect(
(self.rotator_sink, 0),
(self.phy_sink, 0))
# RX & TX synchronization
self.bt_filter = grgsm.burst_type_filter([3])
self.burst_to_fn_time = grgsm.burst_to_fn_time()
# Connections
self.msg_connect(
(self.gsm_receiver, 'C0'),
(self.bt_filter, 'bursts_in'))
self.msg_connect(
(self.bt_filter, 'bursts_out'),
(self.burst_to_fn_time, 'bursts_in'))
self.msg_connect(
(self.burst_to_fn_time, 'fn_time_out'),
(self.tx_time_setter, 'fn_time'))
# AFC (Automatic Frequency Correction)
# NOTE: dummy frequency is used during init
self.gsm_clck_ctrl = grgsm.clock_offset_control(
self.DUMMY_FREQ, phy_sample_rate, osr = self.osr)
self.dict_toggle_sign = dict_toggle_sign()
# Connections
self.msg_connect(
(self.gsm_receiver, 'measurements'),
(self.gsm_clck_ctrl, 'measurements'))
self.msg_connect(
(self.gsm_clck_ctrl, 'ctrl'),
(self.msg_to_tag_src, 'msg'))
self.msg_connect(
(self.gsm_clck_ctrl, 'ctrl'),
(self.dict_toggle_sign, 'dict_in'))
self.msg_connect(
(self.dict_toggle_sign, 'dict_out'),
(self.msg_to_tag_sink, 'msg'))
# Some UHD devices (such as UmTRX) do start the clock
# not from 0, so it's required to reset it manually.
# Resetting UHD source will also affect the sink.
self.phy_src.set_time_now(uhd.time_spec(0.0))
def shutdown(self):
print("[i] Shutdown Radio interface")
self.stop()
self.wait()
@property
def ready(self):
# RX / TX frequencies shall be set
if self.rx_freq is None:
return False
if self.tx_freq is None:
return False
return True
def reset(self):
# TODO: do we need to reset both RX / TX freq.?
# self.rx_freq = None
# self.tx_freq = None
self.set_ta(0)
def calc_phase_inc(self, fc):
return self.ppm / 1.0e6 * 2 * pi * fc / self.sample_rate
def set_rx_freq(self, fc):
if self.freq_offset != 0:
fc += self.freq_offset
print("[#] Shifting RX freq. to %s (offset is %s)"
% (eng_notation.num_to_str(fc),
eng_notation.num_to_str(self.freq_offset)))
self.phy_src.set_center_freq(fc, 0)
self.rotator_src.set_phase_inc(self.calc_phase_inc(fc))
self.gsm_clck_ctrl.set_fc(fc)
self.rx_freq = fc
def set_tx_freq(self, fc):
if self.freq_offset != 0:
fc += self.freq_offset
print("[#] Shifting TX freq. to %s (offset is %s)"
% (eng_notation.num_to_str(fc),
eng_notation.num_to_str(self.freq_offset)))
self.phy_sink.set_center_freq(fc, 0)
self.rotator_sink.set_phase_inc(-self.calc_phase_inc(fc))
self.tx_freq = fc
def set_rx_gain(self, gain):
self.phy_src.set_gain(gain, 0)
self.rx_gain = gain
def set_tx_gain(self, gain):
self.phy_sink.set_gain(gain, 0)
self.tx_gain = gain
def set_slot(self, slot, config):
print("[i] Configure timeslot filter to: %s"
% ("drop all" if config == 0 else "tn=%d" % slot))
if config == 0:
# Value 0 is used for deactivation
self.ts_filter.set_policy(grgsm.FILTER_POLICY_DROP_ALL)
else:
# FIXME: ideally, we should (re)configure the Receiver
# block, but there is no API for that, and hard-coded
# timeslot configuration is used...
self.ts_filter.set_policy(grgsm.FILTER_POLICY_DEFAULT)
self.ts_filter.set_tn(slot)
def set_ta(self, ta):
print("[i] Setting TA value %d" % ta)
advance_time_sec = ta * self.GSM_SYM_PERIOD_uS * 1e-6
self.tx_time_setter.set_timing_advance(advance_time_sec)
def measure(self, freq):
# HACK: generate a random low RSSI value
return random.randint(-120, -100)