1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/* -*- c++ -*- */
/* @file
* @author Piotr Krysik <ptrkrysik@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.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gnuradio/io_signature.h>
#include <grgsm/gsmtap.h>
#include <grgsm/endian.h>
#include <boost/algorithm/clamp.hpp>
#include "cx_channel_hopper_impl.h"
namespace gr {
namespace gsm {
cx_channel_hopper::sptr
cx_channel_hopper::make(const std::vector<int> &ma, int maio, int hsn)
{
return gnuradio::get_initial_sptr
(new cx_channel_hopper_impl(ma, maio, hsn));
}
/*
* The private constructor
*/
cx_channel_hopper_impl::cx_channel_hopper_impl(const std::vector<int> &ma, int maio, int hsn)
: gr::block("cx_channel_hopper",
gr::io_signature::make(0, 0, 0),
gr::io_signature::make(0, 0, 0)),
d_ma(ma),
d_maio(maio),
d_hsn(hsn)
{
d_narfcn = ma.size();
// Check user input for GSM 05.02, p16 compliance
if(d_narfcn < 1 || d_narfcn > 64) {
std::cerr << "warning: clamping number of RFCNs in the MA (" << d_narfcn << "), which should be 1 <= N <= 64." << std::endl;
d_narfcn = boost::algorithm::clamp(d_narfcn, 1, 64);
d_ma.resize(d_narfcn);
}
if(d_maio < 0 || d_maio >= d_narfcn) {
std::cerr << "warning: clamping MAIO (" << d_maio << "), which should be 0 <= MAIO < N." << std::endl;
d_maio = boost::algorithm::clamp(d_maio, 0, d_narfcn - 1);
}
if(d_hsn < 0 || d_hsn > 63) {
std::cerr << "warning: clamping HSN (" << d_hsn << "), which should be 0 <= HSN < 64." << std::endl;
d_hsn = boost::algorithm::clamp(d_hsn, 0, 63);
}
message_port_register_in(pmt::mp("CX"));
set_msg_handler(pmt::mp("CX"), boost::bind(&cx_channel_hopper_impl::assemble_bursts, this, _1));
message_port_register_out(pmt::mp("bursts"));
}
/*
* Our virtual destructor.
*/
cx_channel_hopper_impl::~cx_channel_hopper_impl()
{
}
/**
* Random number table used for calculating the
* hopping sequence. Defined in GSM 05.02.
*/
unsigned char RNTABLE[114] = {
48, 98, 63, 1, 36, 95, 78, 102, 94, 73, \
0, 64, 25, 81, 76, 59, 124, 23, 104, 100, \
101, 47, 118, 85, 18, 56, 96, 86, 54, 2, \
80, 34, 127, 13, 6, 89, 57, 103, 12, 74, \
55, 111, 75, 38, 109, 71, 112, 29, 11, 88, \
87, 19, 3, 68, 110, 26, 33, 31, 8, 45, \
82, 58, 40, 107, 32, 5, 106, 92, 62, 67, \
77, 108, 122, 37, 60, 66, 121, 42, 51, 126, \
117, 114, 4, 90, 43, 52, 53, 113, 120, 72, \
16, 49, 7, 79, 119, 61, 22, 84, 9, 97, \
91, 15, 21, 24, 46, 39, 93, 105, 65, 70, \
125, 99, 17, 123 \
};
/*
* Slow Frequency Hopping (SFH) MAI calculation based
* on airprobe-hopping by Bogdan Diaconescu.
*/
int cx_channel_hopper_impl::calculate_ma_sfh(int maio, int hsn, int n, int fn)
{
int mai = 0;
int s = 0;
int nbin = floor(log2(n) + 1);
int t1 = fn / 1326;
int t2 = fn % 26;
int t3 = fn % 51;
if (hsn == 0)
mai = (fn + maio) % n;
else {
int t1r = t1 % 64;
int m = t2 + RNTABLE[(hsn ^ t1r) + t3];
int mprim = m % (1 << nbin);
int tprim = t3 % (1 << nbin);
if (mprim < n)
s = mprim;
else
s = (mprim + tprim) % n;
mai = (s + maio) % n;
}
return (mai);
}
/**
* Given MA, MAIO, HSN, and FN, decide which frames
* to forward to the demapper.
*/
void cx_channel_hopper_impl::assemble_bursts(pmt::pmt_t msg)
{
pmt::pmt_t header_plus_burst = pmt::cdr(msg);
gsmtap_hdr *header = (gsmtap_hdr *)pmt::blob_data(header_plus_burst);
uint32_t frame_nr = be32toh(header->frame_number);
uint16_t frame_ca = be16toh(header->arfcn) & 0x3FFF; //change highest bits to '0'
//in order to leave only ARFCN number
int mai = calculate_ma_sfh(d_maio, d_hsn, d_narfcn, frame_nr);
if(d_ma[mai] == (int)frame_ca) {
message_port_pub(pmt::mp("bursts"), msg);
}
}
} /* namespace gsm */
} /* namespace gr */
|
