band helper: add unittest for ARFCN validators

Signed-off-by: Carlo Galiotto <[email protected]>

Author: carlo-gal

include/srsran/ran/band_helper.h

@@ -88,7 +88,7 @@ error_type<std::string> is_dl_arfcn_valid_given_band(nr_band              band,
 /// \brief     Checks whether an Uplink ARFCN is valid for a given band.
 /// \param[in] band Given NR band.
 /// \param[in] arfcn_f_ref Given Uplink ARFCN of \c F_REF, as per TS 38.104, Section 5.4.2.1.
-/// \param[in] bw Channel Bandwidth in MHz, which is required to validate some bands' ARFCN values.
+/// \param[in] bw Channel Bandwidth in MHz, which is required only to validate n28.
 /// \return    If the UL ARFCN is invalid for the band, a std::string value is returned with the reason.
 error_type<std::string>
 is_ul_arfcn_valid_given_band(nr_band band, uint32_t arfcn_f_ref, bs_channel_bandwidth bw = bs_channel_bandwidth::MHz10);

lib/ran/band_helper.cpp

@@ -51,7 +51,7 @@ struct nr_band_raster {
 // lower-bound and upper-bound. (FDD, TDD or SDL).
 //
 // NOTE: It only includes FDD, TDD, and SDL bands.
-// NOTE: Band 2 is a subset of band 25
+// NOTE: Band 2 is a subset of band 25.
 // NOTE: Band 41 has two different Freq raster, we only consider raster 15kHz.
 // NOTE: FR2 bands have two different Freq raster, we only consider raster 120kHz.
 const uint32_t                                               nof_nr_DL_bands = 83;
@@ -81,6 +81,9 @@ static constexpr std::array<nr_band_raster, nof_nr_DL_bands> nr_band_table   = {
     {nr_band::n40,   delta_freq_raster::kHz100, 460000, 20,  480000,  460000, 20,  480000},
     {nr_band::n41,   delta_freq_raster::kHz15,  499200,  3,  537999,  499200,  3,  537999},
     {nr_band::n41,   delta_freq_raster::kHz30,  499200,  6,  537996,  499200,  6,  537996},
+    // Band n46 has a raster definded in Table 5.4.2.3-1, TS 38.104, but according to the table notes, only a few ARFCN
+    // values are valid. This range is reported below for completeness, but only the applicable ARFCN given in the
+    // notes will be used.
     {nr_band::n46,   delta_freq_raster::kHz15,  743334,  1,  795000,  743334,  1,  795000},
     {nr_band::n48,   delta_freq_raster::kHz15,  636667,  1,  646666,  636667,  1,  646666},
     {nr_band::n48,   delta_freq_raster::kHz30,  636668,  2,  646666,  636668,  2,  646666},
@@ -117,12 +120,18 @@ static constexpr std::array<nr_band_raster, nof_nr_DL_bands> nr_band_table   = {
     {nr_band::n93,   delta_freq_raster::kHz100, 176000, 20,  183000,  285400, 20,  286400},
     {nr_band::n94,   delta_freq_raster::kHz100, 176000, 20,  183000,  286400, 20,  303400},
     {nr_band::n95,   delta_freq_raster::kHz100, 402000, 20,  405000,       0,  0,       0},
+    // Band n96 has a raster definded in Table 5.4.2.3-1, TS 38.104, but according to the table notes, only a few ARFCN
+    // values are valid. This range is reported below for completeness, but only the applicable ARFCN given in the
+    // notes will be used.
     {nr_band::n96,   delta_freq_raster::kHz15,  795000,  1,  875000,  795000,  1,  875000},
     {nr_band::n97,   delta_freq_raster::kHz100, 460000, 20,  480000,       0,  0,       0},
     {nr_band::n98,   delta_freq_raster::kHz100, 376000, 20,  384000,       0,  0,       0},
     {nr_band::n99,   delta_freq_raster::kHz100, 325300, 20,  332100,       0,  0,       0},
     {nr_band::n100,  delta_freq_raster::kHz100, 174880, 20,  176000,  183880, 20,  185000},
     {nr_band::n101,  delta_freq_raster::kHz100, 380000, 20,  382000,  380000, 20,  382000},
+    // Band n102 has a raster definded in Table 5.4.2.3-1, TS 38.104, but according to the table notes, only a few
+    // ARFCN values are valid. This range is reported below for completeness, but only the applicable ARFCN given in
+    // the notes will be used.
     {nr_band::n102,  delta_freq_raster::kHz15,  796334, 1 ,  828333,  796334,  1,  828333},
     {nr_band::n104,  delta_freq_raster::kHz15,  828334, 1 ,  875000,  828334,  1,  875000},
     {nr_band::n104,  delta_freq_raster::kHz30,  828334, 2 ,  875000,  828334,  2,  875000},
@@ -446,12 +455,8 @@ static nr_raster_params get_raster_params(double freq)
 
 static bool is_valid_raster_param(const nr_raster_params& raster)
 {
-  for (const nr_raster_params& fr : nr_fr_params) {
-    if (fr == raster) {
-      return true;
-    }
-  }
-  return false;
+  return std::any_of(
+      nr_fr_params.begin(), nr_fr_params.end(), [raster](const nr_raster_params& fr) { return fr == raster; });
 }
 
 // Validates band n28, which has an additional ARFCN value to the given interval, as per Table 5.4.2.3-1, TS 38.104,
@@ -489,41 +494,35 @@ static error_type<std::string> validate_band_n28(uint32_t arfcn, bs_channel_band
 // version 17.8.0.
 static error_type<std::string> validate_band_n46(uint32_t arfcn, bs_channel_bandwidth bw)
 {
-  const std::array<unsigned, 2>  n46_b_10_dlarfnc = {782000, 788668};
-  const std::array<unsigned, 32> n46_b_20_dlarfnc = {
+  constexpr std::array<unsigned, 2>  n46_b_10_dlarfnc = {782000, 788668};
+  constexpr std::array<unsigned, 32> n46_b_20_dlarfnc = {
       // clang-format off
       744000, 745332, 746668, 748000, 749332, 750668, 752000, 753332, 754668, 756000, 765332, 766668, 768000, 769332,
       770668, 772000, 773332, 774668, 776000, 777332, 778668, 780000, 781332, 783000, 784332, 785668, 787000, 788332,
       789668, 791000, 792332, 793668
       // clang-format on
   };
-  const std::array<unsigned, 18> n46_b_40_dlarfnc = {
+  constexpr std::array<unsigned, 18> n46_b_40_dlarfnc = {
       // clang-format off
       744668, 746000, 748668, 751332, 754000, 755332, 766000, 767332, 770000, 772668, 775332, 778000, 780668, 783668,
       786332, 787668, 790332, 793000
       // clang-format on
   };
-  const std::array<unsigned, 17> n46_b_60_dlarfnc = {
+  constexpr std::array<unsigned, 17> n46_b_60_dlarfnc = {
       // clang-format off
       745332, 746668, 748000,  752000, 753332, 754668, 766668, 768000, 769332, 773332, 774668, 778668, 780000, 784332,
       785668, 791000, 792332
       // clang-format on
   };
-  const std::array<unsigned, 10> n46_b_80_dlarfnc = {
+  constexpr std::array<unsigned, 10> n46_b_80_dlarfnc = {
       746000, 747332, 752668, 754000, 767332, 768668, 774000, 779332, 785000, 791668};
-  const std::array<unsigned, 4> n46_b_100_dlarfnc = {746668, 753332, 768000, 791000};
-
-  const nr_band_raster band_raster = fetch_band_raster(nr_band::n46, {});
-  if (band_raster.band == srsran::nr_band::invalid or arfcn < band_raster.dl_nref_first or
-      arfcn > band_raster.dl_nref_last) {
-    return make_unexpected(fmt::format("Band n46 channel raster not found"));
-  }
+  constexpr std::array<unsigned, 4> n46_b_100_dlarfnc = {746668, 753332, 768000, 791000};
+  const char*                       error_msg = {"Only a restricted set of DL-ARFCN values are allowed in band n46"};
 
   auto dl_arfcn_exist = [](span<const unsigned> band_list, unsigned dl_arfcn) {
     return std::find(band_list.begin(), band_list.end(), dl_arfcn) != band_list.end();
   };
 
-  const char* error_msg = {"Only a restricted set of DL-ARFCN values are allowed in band n46"};
   switch (bw) {
     case bs_channel_bandwidth::MHz10: {
       return dl_arfcn_exist(span<const unsigned>(n46_b_10_dlarfnc), arfcn) ? error_type<std::string>{}
@@ -558,7 +557,7 @@ static error_type<std::string> validate_band_n46(uint32_t arfcn, bs_channel_band
 // version 17.8.0.
 static error_type<std::string> validate_band_n96(uint32_t arfcn, bs_channel_bandwidth bw)
 {
-  const std::array<unsigned, 59> b_20_dlarfnc = {
+  constexpr std::array<unsigned, 59> b_20_dlarfnc = {
       // clang-format off
       797000, 798332, 799668, 801000, 802332, 803668, 805000, 806332, 807668, 809000, 810332, 811668, 813000, 814332,
       815668, 817000, 818332, 819668, 821000, 822332, 823668, 825000, 826332, 827668, 829000, 830332, 831668, 833000,
@@ -567,38 +566,32 @@ static error_type<std::string> validate_band_n96(uint32_t arfcn, bs_channel_band
       871668, 873000, 874332
       // clang-format on
   };
-  const std::array<unsigned, 29> b_40_dlarfnc = {
+  constexpr std::array<unsigned, 29> b_40_dlarfnc = {
       // clang-format off
       797668, 800332, 803000, 805668, 808332, 811000, 813668, 816332, 819000, 821668, 824332, 827000, 829668, 832332,
       835000, 837668, 840332, 843000, 845668, 848332, 851000, 853668, 856332, 859000, 861668, 864332, 867000, 869668,
       872332
       // clang-format on
   };
-  const std::array<unsigned, 29> b_60_dlarfnc = {
+  constexpr std::array<unsigned, 29> b_60_dlarfnc = {
       // clang-format off
       798332, 799668, 803668, 805000, 809000, 810332, 814332, 815668, 819668, 821000, 825000, 826332, 830332, 831668,
       835668, 837000, 841000, 842332, 846332, 847668, 851668, 853000, 857000, 858332, 862332, 863668, 867668, 869000,
       873000
       // clang-format on
   };
-  const std::array<unsigned, 14> b_80_dlarfnc = {
+  constexpr std::array<unsigned, 14> b_80_dlarfnc = {
       // clang-format off
       799000, 804332, 809668, 815000, 820332, 825668, 831000, 836332, 841668, 847000, 852332, 857668, 863000, 868332
       // clang-format on
   };
-  const std::array<unsigned, 17> b_100_dlarfnc = {
+  constexpr std::array<unsigned, 17> b_100_dlarfnc = {
       // clang-format off
       799668, 803668, 810332, 814332, 821000, 825000, 831668, 835668, 842332, 846332, 853000, 857000, 863668, 867668,
       869000, 870332, 871668
       // clang-format on
   };
 
-  const nr_band_raster band_raster = fetch_band_raster(nr_band::n96, {});
-  if (band_raster.band == srsran::nr_band::invalid or arfcn < band_raster.dl_nref_first or
-      arfcn > band_raster.dl_nref_last) {
-    return make_unexpected(fmt::format("Band n96 channel raster not found"));
-  }
-
   auto dl_arfcn_exist = [](span<const unsigned> band_list, unsigned dl_arfcn) {
     return std::find(band_list.begin(), band_list.end(), dl_arfcn) != band_list.end();
   };
@@ -634,24 +627,24 @@ static error_type<std::string> validate_band_n96(uint32_t arfcn, bs_channel_band
 // version 17.8.0.
 static error_type<std::string> validate_band_n102(uint32_t arfcn, bs_channel_bandwidth bw)
 {
-  const std::array<unsigned, 24> b_20_dlarfnc = {
+  constexpr std::array<unsigned, 24> b_20_dlarfnc = {
       // clang-format off
       797000, 798332, 799668, 801000, 802332, 803668, 805000, 806332, 807668, 809000, 810332, 811668, 813000, 814332,
       815668, 817000, 818332, 819668, 821000, 822332, 823668, 825000, 826332, 827668
       // clang-format on
   };
-  const std::array<unsigned, 12> b_40_dlarfnc = {
+  constexpr std::array<unsigned, 12> b_40_dlarfnc = {
       // clang-format off
       797668, 800332, 803000, 805668, 808332, 811000, 813668, 816332, 819000, 821668, 824332, 827000
       // clang-format on
   };
-  const std::array<unsigned, 12> b_60_dlarfnc = {
+  constexpr std::array<unsigned, 12> b_60_dlarfnc = {
       // clang-format off
       798332, 799668, 803668, 805000, 809000, 810332, 814332, 815668, 819668, 821000, 825000, 826332
       // clang-format on
   };
-  const std::array<unsigned, 6> b_80_dlarfnc  = {799000, 804332, 809668, 815000, 820332, 825668};
-  const std::array<unsigned, 6> b_100_dlarfnc = {799668, 803668, 810332, 814332, 821000, 825000};
+  constexpr std::array<unsigned, 6> b_80_dlarfnc  = {799000, 804332, 809668, 815000, 820332, 825668};
+  constexpr std::array<unsigned, 6> b_100_dlarfnc = {799668, 803668, 810332, 814332, 821000, 825000};
 
   const nr_band_raster band_raster = fetch_band_raster(nr_band::n102, {});
   if (band_raster.band == srsran::nr_band::invalid or arfcn < band_raster.dl_nref_first or
@@ -850,8 +843,11 @@ uint32_t srsran::band_helper::get_ul_arfcn_from_dl_arfcn(uint32_t dl_arfcn, std:
   // Derive UL ARFCN for FDD bands.
   for (const nr_band_raster& b_it : nr_band_table) {
     if (b_it.band == operating_band) {
-      const uint32_t offset = (dl_arfcn - b_it.dl_nref_first) / b_it.dl_nref_step;
-      return (b_it.ul_nref_first + offset * b_it.ul_nref_step);
+      const uint32_t offset             = (dl_arfcn - b_it.dl_nref_first) / b_it.dl_nref_step;
+      const uint32_t candidate_ul_arfcn = b_it.ul_nref_first + offset * b_it.ul_nref_step;
+      // For band n65, n66, n70, n92, n94, the UL spectrum is smaller than the corresponding DL spectrum, therefore we
+      // need to cap the UL ARFCN to its upper-bound.
+      return std::min(candidate_ul_arfcn, b_it.ul_nref_last);
     }
   }