From 3ab5f3a7e8b31fa1f2e6f2e46bca80997aa2a476 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier@softwareradiosystems.com>
Date: Tue, 10 Sep 2019 09:37:46 +0200
Subject: [PATCH] Initial wiener filter integradion in DL channel estimator

---
 .../srslte/phy/ch_estimation/chest_dl.h       |  3 ++
 lib/src/phy/ch_estimation/chest_dl.c          | 38 +++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/lib/include/srslte/phy/ch_estimation/chest_dl.h b/lib/include/srslte/phy/ch_estimation/chest_dl.h
index 0a62354ac..34aaadf08 100644
--- a/lib/include/srslte/phy/ch_estimation/chest_dl.h
+++ b/lib/include/srslte/phy/ch_estimation/chest_dl.h
@@ -45,6 +45,7 @@
 #include "srslte/phy/common/phy_common.h"
 #include "srslte/phy/resampling/interp.h"
 #include "srslte/phy/sync/pss.h"
+#include "wiener_dl.h"
 
 typedef struct SRSLTE_API {
   cf_t*    ce[SRSLTE_MAX_PORTS][SRSLTE_MAX_PORTS];
@@ -79,6 +80,8 @@ typedef struct SRSLTE_API {
   srslte_refsignal_t   csr_refs;
   srslte_refsignal_t** mbsfn_refs;
 
+  srslte_wiener_dl_t* wiener_dl;
+
   cf_t* pilot_estimates;
   cf_t* pilot_estimates_average;
   cf_t* pilot_recv_signal;
diff --git a/lib/src/phy/ch_estimation/chest_dl.c b/lib/src/phy/ch_estimation/chest_dl.c
index 75dc9d90c..ace4af1f9 100644
--- a/lib/src/phy/ch_estimation/chest_dl.c
+++ b/lib/src/phy/ch_estimation/chest_dl.c
@@ -142,6 +142,14 @@ int srslte_chest_dl_init(srslte_chest_dl_t* q, uint32_t max_prb, uint32_t nof_rx
       goto clean_exit;
     }
 
+    q->wiener_dl = calloc(sizeof(srslte_wiener_dl_t), 1);
+    if (q->wiener_dl) {
+      srslte_wiener_dl_init(q->wiener_dl, max_prb, 2, nof_rx_antennas);
+    } else {
+      ERROR("Error allocating wiener filter\n");
+      goto clean_exit;
+    }
+
     q->nof_rx_antennas = nof_rx_antennas;
   }
 
@@ -191,6 +199,10 @@ void srslte_chest_dl_free(srslte_chest_dl_t* q)
   if (q->pilot_recv_signal) {
     free(q->pilot_recv_signal);
   }
+  if (q->wiener_dl) {
+    srslte_wiener_dl_free(q->wiener_dl);
+    free(q->wiener_dl);
+  }
   bzero(q, sizeof(srslte_chest_dl_t));
 }
 
@@ -294,6 +306,11 @@ int srslte_chest_dl_set_cell(srslte_chest_dl_t* q, srslte_cell_t cell)
         fprintf(stderr, "Error initializing interpolator\n");
         return SRSLTE_ERROR;
       }
+
+      if (srslte_wiener_dl_set_cell(q->wiener_dl, cell)) {
+        fprintf(stderr, "Error initializing interpolator\n");
+        return SRSLTE_ERROR;
+      }
     }
     ret = SRSLTE_SUCCESS;
   }
@@ -628,6 +645,27 @@ static void chest_interpolate_noise_est(srslte_chest_dl_t*     q,
     q->noise_estimate[rxant_id][port_id] = estimate_noise_pilots(q, sf, port_id);
   }
 
+  if (q->wiener_dl && ch_mode == SRSLTE_SF_NORM) {
+    uint32_t nre   = q->cell.nof_prb * SRSLTE_NRE;
+    uint32_t nref  = q->cell.nof_prb * 2;
+    uint32_t shift = srslte_refsignal_cs_fidx(q->cell, 0, port_id, 0);
+    for (uint32_t m = 0, l = 0; m < 2 * SRSLTE_CP_NORM_NSYMB; m++) {
+      uint32_t k = srslte_refsignal_cs_nsymbol(l, q->cell.cp, 0);
+      srslte_wiener_dl_run(q->wiener_dl,
+                           port_id,
+                           rxant_id,
+                           m,
+                           shift,
+                           &input[nref * l],
+                           &ce[nre * m],
+                           q->noise_estimate[rxant_id][port_id]);
+
+      if (l == k) {
+        l++;
+      }
+    }
+  }
+
   if (ce != NULL) {
 
     switch (cfg->filter_type) {