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band_helper: add helper to derive UL ARFCN from DL ARFCN

This commit is contained in:
Andre Puschmann 2021-09-08 23:13:27 +02:00
parent dbbc621905
commit 69619d725a
2 changed files with 30 additions and 1 deletions
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11
lib/include/srsran/common/band_helper.h
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@ -59,6 +59,17 @@ public:
*/
uint16_t get_band_from_dl_arfcn(uint32_t arfcn) const;
/**
* @brief Get the respective UL ARFCN of a DL ARFCN
*
* For paired spectrum (FDD) the function returns the respective ARFCN in the same band.
* For unparied spectrum (TDD) the function returns the same ARFCN.
*
* @param dl_arfcn The DL ARFCN
* @return uint32_t
*/
uint32_t get_ul_arfcn_from_dl_arfcn(uint32_t dl_arfcn) const;
/**
* @brief Selects the SSB pattern case according to the band number and subcarrier spacing
* @remark Described by TS 38.101-1 Table 5.4.3.3-1: Applicable SS raster entries per operating band

20
lib/src/common/band_helper.cc
View File

@ -32,7 +32,7 @@ double srsran_band_helper::nr_arfcn_to_freq(uint32_t nr_arfcn)
return (params.F_REF_Offs_MHz * 1e6 + params.delta_F_global_kHz * (nr_arfcn - params.N_REF_Offs) * 1e3);
}
// Implements 5.4.2.1 in TS 38.401
// Implements 5.4.2.1 in TS 38.104
std::vector<uint32_t> srsran_band_helper::get_bands_nr(uint32_t nr_arfcn,
srsran_band_helper::delta_f_raster_t delta_f_raster)
{
@ -79,6 +79,24 @@ uint16_t srsran_band_helper::get_band_from_dl_arfcn(uint32_t arfcn) const
return UINT16_MAX;
}
uint32_t srsran_band_helper::get_ul_arfcn_from_dl_arfcn(uint32_t dl_arfcn) const
{
// return same ARFCN for TDD bands
if (get_duplex_mode(get_band_from_dl_arfcn(dl_arfcn)) == SRSRAN_DUPLEX_MODE_TDD) {
return dl_arfcn;
}
// derive UL ARFCN for FDD bands
for (const auto& band : nr_band_table_fr1) {
if (band.band == get_band_from_dl_arfcn(dl_arfcn)) {
uint32_t offset = (dl_arfcn - band.dl_nref_first) / band.dl_nref_step;
return (band.ul_nref_first + offset * band.ul_nref_step);
}
}
return UINT16_MAX;
}
srsran_ssb_patern_t srsran_band_helper::get_ssb_pattern(uint16_t band, srsran_subcarrier_spacing_t scs) const
{
// Look for the given band and SCS