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
|
#include <stdint.h>
#include <osmocom/core/bits.h>
#include "gsm0503_tables.h"
#include "gsm0503_interleaving.h"
/*
* GSM xCCH interleaving and burst mapping
*
* Interleaving:
*
* Given 456 coded input bits, form 4 blocks of 114 bits:
*
* i(B, j) = c(n, k) k = 0, ..., 455
* n = 0, ..., N, N + 1, ...
* B = B_0 + 4n + (k mod 4)
* j = 2(49k mod 57) + ((k mod 8) div 4)
*
* Mapping on Burst:
*
* e(B, j) = i(B, j)
* e(B, 59 + j) = i(B, 57 + j) j = 0, ..., 56
* e(B, 57) = h_l(B)
* e(B, 58) = h_n(B)
*
* Where hl(B) and hn(B) are bits in burst B indicating flags.
*/
void gsm0503_xcch_deinterleave(sbit_t *cB, sbit_t *iB)
{
int j, k, B;
for (k=0; k<456; k++) {
B = k & 3;
j = 2 * ((49 * k) % 57) + ((k & 7) >> 2);
cB[k] = iB[B * 114 + j];
}
}
void gsm0503_xcch_interleave(ubit_t *cB, ubit_t *iB)
{
int j, k, B;
for (k=0; k<456; k++) {
B = k & 3;
j = 2 * ((49 * k) % 57) + ((k & 7) >> 2);
iB[B * 114 + j] = cB[k];
}
}
/*
* GSM TCH FR/EFR/AFS interleaving and burst mapping
*
* Interleaving:
*
* Given 456 coded input bits, form 8 blocks of 114 bits,
* where even bits of the first 4 blocks and odd bits of the last 4 blocks
* are used:
*
* i(B, j) = c(n, k) k = 0, ..., 455
* n = 0, ..., N, N + 1, ...
* B = B_0 + 4n + (k mod 8)
* j = 2(49k mod 57) + ((k mod 8) div 4)
*
* Mapping on Burst:
*
* e(B, j) = i(B, j)
* e(B, 59 + j) = i(B, 57 + j) j = 0, ..., 56
* e(B, 57) = h_l(B)
* e(B, 58) = h_n(B)
*
* Where hl(B) and hn(B) are bits in burst B indicating flags.
*/
void gsm0503_tch_fr_deinterleave(sbit_t *cB, sbit_t *iB)
{
int j, k, B;
for (k=0; k<456; k++) {
B = k & 7;
j = 2 * ((49 * k) % 57) + ((k & 7) >> 2);
cB[k] = iB[B * 114 + j];
}
}
void gsm0503_tch_fr_interleave(ubit_t *cB, ubit_t *iB)
{
int j, k, B;
for (k=0; k<456; k++) {
B = k & 7;
j = 2 * ((49 * k) % 57) + ((k & 7) >> 2);
iB[B * 114 + j] = cB[k];
}
}
|
