183 lines
6.0 KiB
Python
183 lines
6.0 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# @file
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# @author (C) 2015 by Roman Khassraf <rkhassraf@gmail.com>
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# (C) 2017 by Piotr Krysik <ptrkrysik@gmail.com>
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# @section LICENSE
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#
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# Gr-gsm is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# any later version.
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#
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# Gr-gsm is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with gr-gsm; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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#
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import collections
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__chan_spacing = 2e5
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__arfcn_pcs = 0x8000
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# first uplink freq, distance between uplink/downlink frequency, list of range tuple
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# each tuple in a range tuple contains: first arfcn of the range, last arfcn of the range, offset of the range
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# entries are ordered by relevance
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__band_conf = collections.OrderedDict([
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('GSM900', {'f_start': 880.2e6, 'distance': 45e6, 'ranges': [(975, 1023), (0, 124)]}),
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('DCS1800', {'f_start': 1710.2e6, 'distance': 95e6, 'ranges': [(512, 885)]}),
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('GSM850', {'f_start': 824.2e6, 'distance': 45e6, 'ranges': [(128, 251)]}),
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('PCS1900', {'f_start': 1850.2e6, 'distance': 80e6, 'ranges': [(512+__arfcn_pcs, 810+__arfcn_pcs)]}), #PCS band is "special" as its channel number range overlap with DCS1800
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('GSM450', {'f_start': 450.6e6, 'distance': 10e6, 'ranges': [(259, 293)]}),
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('GSM480', {'f_start': 479e6, 'distance': 10e6, 'ranges': [(306, 340)]}),
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('GSM-R', {'f_start': 876.2e6, 'distance': 45e6, 'ranges': [(955, 1023), (0, 124)]}),
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])
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def get_bands():
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return __band_conf.keys()
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def arfcn2band(arfcn):
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for band_name,band_desc in __band_conf.items():
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for arfcns_range in band_desc["ranges"]:
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arfcn_start = arfcns_range[0]
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arfcn_stop = arfcns_range[1]
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if arfcn_start <= arfcn <= arfcn_stop:
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return band_name
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return None
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def freq2band(freq, downlink=False):
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for band_name,band_desc in __band_conf.items():
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chans_total = 0
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#count total number of channels in the range
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for arfcns_range in band_desc["ranges"]:
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arfcn_start = arfcns_range[0]
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arfcn_stop = arfcns_range[1]
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chans_in_range = arfcn_stop - arfcn_start + 1
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chans_total = chans_total + chans_in_range
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first_freq = band_desc["f_start"]
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if downlink:
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first_freq = first_freq + band_desc["distance"]
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last_freq = first_freq + (chans_total - 1) * __chan_spacing
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if first_freq <= freq <= last_freq:
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return band_name
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return None
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def uplink2band(freq):
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return freq2band(freq, False)
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def downlink2band(freq):
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return freq2band(freq, True)
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def is_valid_arfcn(arfcn):
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"""
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Returns True if arfcn is valid in the given band, else False
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"""
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band = arfcn2band(arfcn)
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if band is not None:
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conf = __band_conf.get(band)
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for arfcn_range in conf['ranges']:
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arfcn_start = arfcn_range[0]
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arfcn_end = arfcn_range[1]
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if arfcn_start <= arfcn <= arfcn_end:
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return True
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return False
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def is_valid_uplink(freq):
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"""
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Returns True if the given frequency is a valid uplink frequency in the given band
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"""
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result = False
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band = uplink2band(freq)
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if band is not None:
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result = True
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return result
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def is_valid_downlink(freq):
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"""
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Returns True if the given frequency is a valid downlink frequency in the given band
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"""
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result = False
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band = downlink2band(freq)
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if band is not None:
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result = True
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return result
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def arfcn2uplink(arfcn):
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band = arfcn2band(arfcn)
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if band is not None:
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conf = __band_conf.get(band)
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f_start = conf['f_start']
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arfcns_total = 0
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for arfcn_range in conf['ranges']:
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arfcn_start = arfcn_range[0]
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arfcn_end = arfcn_range[1]
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if arfcn_start <= arfcn <= arfcn_end:
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f = f_start + (__chan_spacing * (arfcn - arfcn_start + arfcns_total))
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return round(f, 1)
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arfcns_total = arfcn_end - arfcn_start + 1
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return -1
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def arfcn2downlink(arfcn):
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band = arfcn2band(arfcn)
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if band is not None:
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conf = __band_conf.get(band)
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distance = conf['distance']
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return round(arfcn2uplink(arfcn) + distance, 1)
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return -1
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def uplink2arfcn(freq):
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band = uplink2band(freq)
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if band is not None:
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conf = __band_conf.get(band)
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arfcns_total = 0
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for arfcn_range in conf['ranges']:
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arfcn_start = arfcn_range[0]
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arfcn_end = arfcn_range[1]
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arfcns_in_range = arfcn_end - arfcn_start + 1
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freq_start = conf['f_start'] + arfcns_total * __chan_spacing
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freq_end = freq_start + (arfcns_in_range - 1) * __chan_spacing
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if freq_start <= freq <= freq_end:
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arfcn = int(round(arfcn_start + ((freq - freq_start) / __chan_spacing), 0))
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return arfcn
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arfcns_total = arfcns_total + arfcns_in_range
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return -1
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def downlink2arfcn(freq):
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band = downlink2band(freq)
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if band is not None:
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conf = __band_conf.get(band)
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distance = conf['distance']
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freq_uplink = freq - distance
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return int(round(uplink2arfcn(freq_uplink), 0))
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return -1
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def get_arfcn_ranges(band):
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"""
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Returns a list of arfcn tuples, each with first and last arfcn of the range.
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"""
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result = []
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if band in __band_conf:
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conf = __band_conf.get(band)
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for arfcn_range in conf['ranges']:
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arfcn_tuple = (arfcn_range[0], arfcn_range[1])
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result.append(arfcn_tuple)
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return result
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