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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @file
# @author (C) 2015 by Roman Khassraf <rkhassraf@gmail.com>
# @section LICENSE
#
# Gr-gsm 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 3, or (at your option)
# any later version.
#
# Gr-gsm 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 gr-gsm; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
#
import collections
# first uplink freq, distance between uplink/downlink frequency, list of range tuple
# each tuple in a range tuple contains: first arfcn of the range, last arfcn of the range, offset of the range
# entries are ordered by relevance
__band_conf = collections.OrderedDict([
('P-GSM', {'f_start': 890.0e6, 'distance': 45e6, 'ranges': [(1, 124, 0)]}),
('DCS1800', {'f_start': 1710.2e6, 'distance': 95e6, 'ranges': [(512, 885, 512)]}),
('PCS1900', {'f_start': 1850.2e6, 'distance': 80e6, 'ranges': [(512, 810, 512)]}),
('E-GSM', {'f_start': 890.0e6, 'distance': 45e6, 'ranges': [(0, 124, 0), (975, 1023, 1024)]}),
('R-GSM', {'f_start': 890.0e6, 'distance': 45e6, 'ranges': [(0, 124, 0), (955, 1023, 1024)]}),
('GSM450', {'f_start': 450.6e6, 'distance': 10e6, 'ranges': [(259, 293, 259)]}),
('GSM480', {'f_start': 479e6, 'distance': 10e6, 'ranges': [(306, 340, 306)]}),
('GSM850', {'f_start': 824.2e6, 'distance': 45e6, 'ranges': [(128, 251, 128)]}),
])
__chan_spacing = 2e5
def get_bands():
return __band_conf.keys()
def is_valid_arfcn(arfcn, band):
"""
Returns True if arfcn is valid in the given band, else False
"""
if band in __band_conf:
conf = __band_conf.get(band)
for arfcn_range in conf['ranges']:
arfcn_start = arfcn_range[0]
arfcn_end = arfcn_range[1]
if arfcn_start <= arfcn <= arfcn_end:
return True
return False
def is_valid_uplink(freq, band):
"""
Returns True if the given frequency is a valid uplink frequency in the given band
"""
result = None
if band in __band_conf:
conf = __band_conf.get(band)
result = False
for arfcn_range in conf['ranges']:
arfcn_start = arfcn_range[0]
arfcn_end = arfcn_range[1]
first_freq = arfcn2uplink(arfcn_start, band)
last_freq = arfcn2uplink(arfcn_end, band)
if first_freq is None or last_freq is None:
result = False
elif first_freq <= freq <= last_freq:
result = True
return result
def is_valid_downlink(freq, band):
"""
Returns True if the given frequency is a valid downlink frequency in the given band
"""
result = None
if band in __band_conf:
conf = __band_conf.get(band)
result = False
for arfcn_range in conf['ranges']:
arfcn_start = arfcn_range[0]
arfcn_end = arfcn_range[1]
first_freq = arfcn2downlink(arfcn_start, band)
last_freq = arfcn2downlink(arfcn_end, band)
if first_freq is None or last_freq is None:
result = False
elif first_freq <= freq <= last_freq:
result = True
return result
def arfcn2uplink(arfcn, band):
if band in __band_conf and is_valid_arfcn(arfcn, band):
conf = __band_conf.get(band)
f_start = conf['f_start']
offset = None
for arfcn_range in conf['ranges']:
arfcn_start = arfcn_range[0]
arfcn_end = arfcn_range[1]
if arfcn_start <= arfcn <= arfcn_end:
offset = arfcn_range[2]
if offset is not None:
f = f_start + (__chan_spacing * (arfcn - offset))
return round(f, 1)
return None
def arfcn2downlink(arfcn, band):
if band in __band_conf and is_valid_arfcn(arfcn, band):
conf = __band_conf.get(band)
distance = conf['distance']
return round(arfcn2uplink(arfcn, band) + distance, 1)
return None
def uplink2arfcn(freq, band):
if band in __band_conf and is_valid_uplink(freq, band):
conf = __band_conf.get(band)
f_start = conf['f_start']
offset = None
for arfcn_range in conf['ranges']:
arfcn_start = arfcn_range[0]
arfcn_end = arfcn_range[1]
offset = arfcn_range[2]
arfcn = int(round(offset + ((freq - f_start) / __chan_spacing), 0))
if arfcn_start <= arfcn <= arfcn_end:
return arfcn
return None
def downlink2arfcn(freq, band):
if band in __band_conf and is_valid_downlink(freq, band):
conf = __band_conf.get(band)
distance = conf['distance']
freq_uplink = freq - distance
return int(round(uplink2arfcn(freq_uplink, band), 0))
return None
def get_arfcn_ranges(band):
"""
Returns a list of arfcn tuples, each with first and last arfcn of the range.
"""
result = []
if band in __band_conf:
conf = __band_conf.get(band)
for arfcn_range in conf['ranges']:
arfcn_tuple = (arfcn_range[0], arfcn_range[1])
result.append(arfcn_tuple)
return result
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