|
1
|
/**
|
|
2
|
* Simple 8-bit vs 11-bit RACH collision test for libosmocoding.
|
|
3
|
* cc rach_test.c `pkg-config --libs libosmocoding --cflags libosmocoding` -o rach_test
|
|
4
|
*/
|
|
5
|
|
|
6
|
#include <stdbool.h>
|
|
7
|
#include <stdint.h>
|
|
8
|
#include <stdio.h>
|
|
9
|
|
|
10
|
#include <osmocom/core/bits.h>
|
|
11
|
#include <osmocom/core/utils.h>
|
|
12
|
#include <osmocom/coding/gsm0503_coding.h>
|
|
13
|
|
|
14
|
#define RACH_PAYLOAD_LEN 36
|
|
15
|
|
|
16
|
static unsigned int count_11b28b_collisions = 0;
|
|
17
|
static unsigned int count_8b211b_collisions = 0;
|
|
18
|
|
|
19
|
/* Encoding as 11-bit, decoding as 8-bit */
|
|
20
|
static void test_11b28b_collisions(uint16_t ra11, uint8_t bsic)
|
|
21
|
{
|
|
22
|
ubit_t ubuf[RACH_PAYLOAD_LEN];
|
|
23
|
sbit_t sbuf[RACH_PAYLOAD_LEN];
|
|
24
|
uint16_t _ra11;
|
|
25
|
uint8_t ra8;
|
|
26
|
int rc;
|
|
27
|
|
|
28
|
/* Encode an extended (11-bit) RACH */
|
|
29
|
rc = gsm0503_rach_ext_encode(ubuf, ra11, bsic, true);
|
|
30
|
OSMO_ASSERT(rc == 0);
|
|
31
|
|
|
32
|
/* Convert hard-bits to soft-bits */
|
|
33
|
osmo_ubit2sbit(sbuf, ubuf, RACH_PAYLOAD_LEN);
|
|
34
|
|
|
35
|
/* Self-test: attempt to decode as extended (11-bit) RACH */
|
|
36
|
rc = gsm0503_rach_ext_decode_ber(&_ra11, sbuf, bsic, NULL, NULL);
|
|
37
|
OSMO_ASSERT(rc == 0 && ra11 == _ra11);
|
|
38
|
|
|
39
|
/* Attempt to decode as a regular (8-bit) RACH */
|
|
40
|
rc = gsm0503_rach_decode_ber(&ra8, sbuf, bsic, NULL, NULL);
|
|
41
|
if (rc == 0) {
|
|
42
|
printf("Successfully decoded 11-bit (0x%04x) RACH as 8-bit (0x%02x): bsic=0x%02x\n",
|
|
43
|
ra11, ra8, bsic);
|
|
44
|
count_11b28b_collisions++;
|
|
45
|
}
|
|
46
|
}
|
|
47
|
|
|
48
|
/* Encoding as 8-bit, decoding as 11-bit */
|
|
49
|
static int test_8b11b_collisions(uint8_t ra8, uint8_t bsic)
|
|
50
|
{
|
|
51
|
ubit_t ubuf[RACH_PAYLOAD_LEN];
|
|
52
|
sbit_t sbuf[RACH_PAYLOAD_LEN];
|
|
53
|
uint16_t ra11;
|
|
54
|
uint8_t _ra8;
|
|
55
|
int rc;
|
|
56
|
|
|
57
|
/* Encode a regular (8-bit) RACH */
|
|
58
|
rc = gsm0503_rach_ext_encode(ubuf, ra8, bsic, false);
|
|
59
|
OSMO_ASSERT(rc == 0);
|
|
60
|
|
|
61
|
/* Convert hard-bits to soft-bits */
|
|
62
|
osmo_ubit2sbit(sbuf, ubuf, RACH_PAYLOAD_LEN);
|
|
63
|
|
|
64
|
/* Self-test: attempt to decode as regular (8-bit) RACH */
|
|
65
|
rc = gsm0503_rach_decode_ber(&_ra8, sbuf, bsic, NULL, NULL);
|
|
66
|
OSMO_ASSERT(rc == 0 && ra8 == _ra8);
|
|
67
|
|
|
68
|
/* Attempt to decode as an extended (11-bit) RACH */
|
|
69
|
rc = gsm0503_rach_ext_decode_ber(&ra11, sbuf, bsic, NULL, NULL);
|
|
70
|
if (rc == 0) {
|
|
71
|
printf("Successfully decoded 8-bit (0x%02x) RACH as 11-bit (0x%04x): bsic=0x%02x\n",
|
|
72
|
ra8, ra11, bsic);
|
|
73
|
count_8b211b_collisions++;
|
|
74
|
}
|
|
75
|
}
|
|
76
|
|
|
77
|
int main(int argc, char **argv)
|
|
78
|
{
|
|
79
|
uint8_t bsic;
|
|
80
|
int i, rc;
|
|
81
|
|
|
82
|
printf("=== Looking for possible collisions: decoding 8-bit RACH as 11-bit\n");
|
|
83
|
for (bsic = 0; bsic <= 63; bsic++)
|
|
84
|
for (i = 0; i <= 0xff; i++)
|
|
85
|
test_8b11b_collisions((uint8_t) i, bsic);
|
|
86
|
|
|
87
|
puts("");
|
|
88
|
|
|
89
|
printf("=== Looking for possible collisions: decoding 11-bit RACH as 8-bit\n");
|
|
90
|
for (bsic = 0; bsic <= 63; bsic++)
|
|
91
|
for (i = 0; i <= 0x7ff; i++)
|
|
92
|
test_11b28b_collisions((uint16_t) i, bsic);
|
|
93
|
|
|
94
|
puts("");
|
|
95
|
|
|
96
|
printf("=== Results: \n");
|
|
97
|
printf(" - decoding 8-bit RACH as 11-bit: %u\n", count_8b211b_collisions);
|
|
98
|
printf(" - decoding 11-bit RACH as 8-bit: %u\n", count_11b28b_collisions);
|
|
99
|
|
|
100
|
return 0;
|
|
101
|
}
|
