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utils/fn_time: added clock_error to fn_time_delta 

Information about clock error is needed in order to transform frame number
to hardware time - which is not ideal (i.e. different than BTS time).

Change-Id: Icd77b88da0490d6c9565bf3df0342574b91aae6e
This commit is contained in:
Piotr Krysik 2019-07-17 09:34:22 +02:00
parent c5ed04572f
commit 43dfbdf1a9
2 changed files with 9 additions and 6 deletions
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2
include/grgsm/misc_utils/fn_time.h
View File

@ -46,7 +46,7 @@ namespace gr {
typedef std::pair<unsigned long long, double> time_format;
GRGSM_API time_format fn_time_delta_cpp(uint32_t fn_ref, time_format time_ref, uint32_t fn_x,
time_format time_hint, uint32_t ts_num, uint32_t ts_ref);
time_format time_hint, uint32_t ts_num, uint32_t ts_ref, double clock_error=0.0);
} // namespace gsm
} // namespace gr

13
lib/misc_utils/fn_time.cc
View File

@ -29,7 +29,7 @@
#define GSM_SYM_RATE (13.0e6 / 48.0)
#define GSM_TS_PERIOD (156.25 / GSM_SYM_RATE)
#define GSM_FN_PERIOD (8 * GSM_TS_PERIOD)
#define GSM_FRAME_PERIOD (8 * GSM_TS_PERIOD)
namespace gr {
namespace gsm {
@ -62,7 +62,7 @@ namespace gr {
time_spec_t time_diff_hint)
{
int frames_diff, fn_delta;
frames_diff = int(round(time_diff_hint.get_real_secs() / GSM_FN_PERIOD));
frames_diff = int(round(time_diff_hint.get_real_secs() / GSM_FRAME_PERIOD));
fn_delta = fnmod_delta(fn, fn_ref + frames_diff) + frames_diff;
return fn_delta;
@ -80,11 +80,14 @@ namespace gr {
* @return difference between fn_ref and fn
*/
time_format fn_time_delta_cpp(uint32_t fn_ref, time_format time_ref, uint32_t fn_x,
time_format time_hint, uint32_t ts_num, uint32_t ts_ref)
time_format time_hint, uint32_t ts_num, uint32_t ts_ref, double clock_error)
{
time_spec_t time_diff_hint = time_spec_t(time_hint.first, time_hint.second) - time_spec_t(time_ref.first, time_ref.second);
time_spec_t time_diff_hint = time_spec_t(time_hint.first, time_hint.second)
- time_spec_t(time_ref.first, time_ref.second);
int fn_delta = fn_time_diff_delta(fn_x, fn_ref, time_diff_hint);
time_spec_t time_x_precise = fn_delta * GSM_FN_PERIOD + time_spec_t(time_ref.first, time_ref.second) + (static_cast<int>(ts_num) - static_cast<int>(ts_ref)) * GSM_TS_PERIOD;
time_spec_t time_x_precise = (fn_delta * GSM_FRAME_PERIOD)*(1.0-clock_error)
+ time_spec_t(time_ref.first, time_ref.second)
+ (static_cast<int>(ts_num) - static_cast<int>(ts_ref)) * GSM_TS_PERIOD;
return time_format(time_x_precise.get_full_secs(), time_x_precise.get_frac_secs());
}