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PHY: make sf_extension a parameter

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This parameter is meaningful in TDD, to decide
when to start DL at eNB side. Since there is a
need for the PA to be operational, we need to
transmit a bit before the DL subframe coming
after an UL subframe. (We transmit zeros.)

We used to use N_TA_offset which may be too much.
Default value is now N_TA_offset/2 and can be
changed in the configuration file, in the RUs
section, like:

RUs = (
    {
       local_rf       = "yes"
         nb_tx          = 1
         nb_rx          = 1
         att_tx         = 0
         att_rx         = 0;
         bands          = [7];
         max_pdschReferenceSignalPower = -27;
         max_rxgain                    = 105;
         eNB_instances  = [0];
         sf_extension = 312;
    }
);

N_TA_offset is 624 (for 30.72MHz). In the example
above, we set sf_extension = 312, which is also
the default.

The value to put in the configuration file is for
30.72MHz. The value is scaled accordingly at runtime
(thus only one value to set for every RB configuration,
25, 50 or 100, leading to less problems when adapting
configuration files).

This option is for experts and should not be changed
randomly.
This commit is contained in:
Cedric Roux
2019-03-19 09:25:43 +01:00
parent 69ccf51f96
commit ee5b739019
3 changed files with 18 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
targets/RT/USER/lte-ru.c
+12 -2
View File
@@ -835,7 +835,7 @@ void tx_rf(RU_t *ru) {
(prevSF_type == SF_UL) &&
(nextSF_type == SF_DL)) {
flags = 2; // start of burst
sf_extension = ru->N_TA_offset;
sf_extension = ru->sf_extension;
}
if ((fp->frame_type == TDD) &&
@@ -843,7 +843,7 @@ void tx_rf(RU_t *ru) {
(prevSF_type == SF_UL) &&
(nextSF_type == SF_UL)) {
flags = 4; // start of burst and end of burst (only one DL SF between two UL)
sf_extension = ru->N_TA_offset;
sf_extension = ru->sf_extension;
}
#if defined(__x86_64) || defined(__i386__)
@@ -1386,6 +1386,14 @@ int setup_RU_buffers(RU_t *ru) {
* TODO: find a proper cleaner solution
*/
ru->N_TA_offset = 0;
if (frame_parms->N_RB_DL == 100) /* no scaling to do */;
else if (frame_parms->N_RB_DL == 50) ru->sf_extension /= 2;
else if (frame_parms->N_RB_DL == 25) ru->sf_extension /= 4;
else { printf("not handled, todo\n"); exit(1); }
} else {
ru->N_TA_offset = 0;
ru->sf_extension = 0;
}
if (ru->openair0_cfg.mmapped_dma == 1) {
@@ -2883,6 +2891,8 @@ void RCconfig_RU(void) {
RC.ru[j]->max_pdschReferenceSignalPower = *(RUParamList.paramarray[j][RU_MAX_RS_EPRE_IDX].uptr);;
RC.ru[j]->max_rxgain = *(RUParamList.paramarray[j][RU_MAX_RXGAIN_IDX].uptr);
RC.ru[j]->num_bands = RUParamList.paramarray[j][RU_BAND_LIST_IDX].numelt;
/* sf_extension is in unit of samples for 30.72MHz here, has to be scaled later */
RC.ru[j]->sf_extension = *(RUParamList.paramarray[j][RU_SF_EXTENSION_IDX].uptr);
for (i=0; i<RC.ru[j]->num_bands; i++) RC.ru[j]->band[i] = RUParamList.paramarray[j][RU_BAND_LIST_IDX].iptr[i];
} //strcmp(local_rf, "yes") == 0