From 7ba5099bee74a8013a49e5b2d87abfc7efa222ab Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier.arteaga@softwareradiosystems.com>
Date: Mon, 20 Sep 2021 10:53:09 +0200
Subject: [PATCH] Implement CSI-RS resource mapping validation

---
 .../srsran/phy/ch_estimation/csi_rs_cfg.h     |  2 ++
 lib/src/asn1/rrc_nr_utils.cc                  | 17 ++++++++++++++
 lib/src/phy/ch_estimation/csi_rs.c            | 23 +++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/lib/include/srsran/phy/ch_estimation/csi_rs_cfg.h b/lib/include/srsran/phy/ch_estimation/csi_rs_cfg.h
index 3da47d268..1be7edf90 100644
--- a/lib/include/srsran/phy/ch_estimation/csi_rs_cfg.h
+++ b/lib/include/srsran/phy/ch_estimation/csi_rs_cfg.h
@@ -128,4 +128,6 @@ typedef struct SRSRAN_API {
   uint32_t                    count;                                        ///< Number of resources in the set
 } srsran_csi_rs_zp_set_t;
 
+SRSRAN_API bool srsran_csi_rs_resource_mapping_is_valid(const srsran_csi_rs_resource_mapping_t *res);
+
 #endif // SRSRAN_CSI_RS_CFG_H
diff --git a/lib/src/asn1/rrc_nr_utils.cc b/lib/src/asn1/rrc_nr_utils.cc
index 32c386a74..679b38067 100644
--- a/lib/src/asn1/rrc_nr_utils.cc
+++ b/lib/src/asn1/rrc_nr_utils.cc
@@ -1070,6 +1070,15 @@ bool make_phy_zp_csi_rs_resource(const asn1::rrc_nr::zp_csi_rs_res_s& zp_csi_rs_
   }
   zp_csi_rs_resource.resource_mapping.freq_band.nof_rb   = zp_csi_rs_res.res_map.freq_band.nrof_rbs;
   zp_csi_rs_resource.resource_mapping.freq_band.start_rb = zp_csi_rs_res.res_map.freq_band.start_rb;
+
+  // Validate CSI-RS resource mapping
+  if (not srsran_csi_rs_resource_mapping_is_valid(&zp_csi_rs_resource.resource_mapping)) {
+    asn1::json_writer json_writer;
+    zp_csi_rs_res.res_map.to_json(json_writer);
+    asn1::log_error("Resource mapping is invalid or not implemented: %s", json_writer.to_string());
+    return false;
+  }
+
   if (zp_csi_rs_res.periodicity_and_offset_present) {
     switch (zp_csi_rs_res.periodicity_and_offset.type()) {
       case csi_res_periodicity_and_offset_c::types_opts::options::slots4:
@@ -1228,6 +1237,14 @@ bool make_phy_nzp_csi_rs_resource(const asn1::rrc_nr::nzp_csi_rs_res_s& asn1_nzp
   csi_rs_nzp_resource.resource_mapping.freq_band.nof_rb   = asn1_nzp_csi_rs_res.res_map.freq_band.nrof_rbs;
   csi_rs_nzp_resource.resource_mapping.freq_band.start_rb = asn1_nzp_csi_rs_res.res_map.freq_band.start_rb;
 
+  // Validate CSI-RS resource mapping
+  if (not srsran_csi_rs_resource_mapping_is_valid(&csi_rs_nzp_resource.resource_mapping)) {
+    asn1::json_writer json_writer;
+    asn1_nzp_csi_rs_res.res_map.to_json(json_writer);
+    asn1::log_error("Resource mapping is invalid or not implemented: %s", json_writer.to_string());
+    return false;
+  }
+
   csi_rs_nzp_resource.power_control_offset = asn1_nzp_csi_rs_res.pwr_ctrl_offset;
   if (asn1_nzp_csi_rs_res.pwr_ctrl_offset_ss_present) {
     csi_rs_nzp_resource.power_control_offset_ss = asn1_nzp_csi_rs_res.pwr_ctrl_offset_ss.to_number();
diff --git a/lib/src/phy/ch_estimation/csi_rs.c b/lib/src/phy/ch_estimation/csi_rs.c
index cfe490705..6c7c3920b 100644
--- a/lib/src/phy/ch_estimation/csi_rs.c
+++ b/lib/src/phy/ch_estimation/csi_rs.c
@@ -232,6 +232,29 @@ static int csi_rs_nof_cdm_groups(const srsran_csi_rs_resource_mapping_t* resourc
   return SRSRAN_ERROR;
 }
 
+bool srsran_csi_rs_resource_mapping_is_valid(const srsran_csi_rs_resource_mapping_t* res)
+{
+  if (res == NULL) {
+    return false;
+  }
+
+  if (csi_rs_nof_cdm_groups(res) < 1) {
+    return false;
+  }
+
+  uint32_t l_list[CSI_RS_MAX_SYMBOLS_SLOT] = {};
+  if (csi_rs_location_get_l_list(res, 0, l_list) < SRSRAN_SUCCESS) {
+    return false;
+  }
+
+  uint32_t k_list[CSI_RS_MAX_SUBC_PRB] = {};
+  if (csi_rs_location_get_k_list(res, 0, k_list) < SRSRAN_SUCCESS) {
+    return false;
+  }
+
+  return true;
+}
+
 uint32_t csi_rs_count(srsran_csi_rs_density_t density, uint32_t nprb)
 {
   switch (density) {