From b872f84255565db017657d7c38901af571b2fc75 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier@softwareradiosystems.com>
Date: Tue, 29 Aug 2017 16:54:33 +0200
Subject: [PATCH] Improved RI selection

(cherry picked from commit 034025d)
---
 lib/src/phy/phch/pdsch.c |  2 +-
 lib/src/phy/ue/ue_dl.c   | 21 +++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lib/src/phy/phch/pdsch.c b/lib/src/phy/phch/pdsch.c
index bf50cb6ec..62f2834ae 100644
--- a/lib/src/phy/phch/pdsch.c
+++ b/lib/src/phy/phch/pdsch.c
@@ -683,7 +683,7 @@ int srslte_pdsch_pmi_select(srslte_pdsch_t *q,
                                   uint32_t pmi[SRSLTE_MAX_LAYERS], float sinr[SRSLTE_MAX_LAYERS][SRSLTE_MAX_CODEBOOKS]) {
 
   if (q->cell.nof_ports == 2 && q->nof_rx_antennas == 2) {
-    for (int nof_layers = 1; nof_layers <= cfg->nof_layers; nof_layers++ ) {
+    for (int nof_layers = 1; nof_layers <= 2; nof_layers++ ) {
       if (sinr[nof_layers - 1] && pmi) {
         if (srslte_precoding_pmi_select(ce, nof_ce, noise_estimate, nof_layers, &pmi[nof_layers - 1],
                                         sinr[nof_layers - 1]) < 0) {
diff --git a/lib/src/phy/ue/ue_dl.c b/lib/src/phy/ue/ue_dl.c
index 91116ab70..55f65ad3d 100644
--- a/lib/src/phy/ue/ue_dl.c
+++ b/lib/src/phy/ue/ue_dl.c
@@ -438,9 +438,15 @@ int srslte_ue_dl_decode_rnti_multi(srslte_ue_dl_t *q, cf_t *input[SRSLTE_MAX_POR
                                     q->sf_symbols_m, q->ce_m, 
                                     noise_estimate, 
                                     rnti, data, acks);
-      
+
+      for (int tb = 0; tb < q->pdsch_cfg.grant.nof_tb; tb++) {
+        if (!acks[tb]) {
+          q->pkt_errors++;
+        }
+        q->pkts_total++;
+      }
+
       if (ret == SRSLTE_ERROR) {
-        q->pkt_errors++;
       } else if (ret == SRSLTE_ERROR_INVALID_INPUTS) {
         fprintf(stderr, "Error calling srslte_pdsch_decode()\n");      
       }
@@ -458,8 +464,6 @@ int srslte_ue_dl_decode_rnti_multi(srslte_ue_dl_t *q, cf_t *input[SRSLTE_MAX_POR
   
   }
 
-  q->pkts_total++;
-
   if (found_dci == 1 && ret == SRSLTE_SUCCESS) { 
     return q->pdsch_cfg.grant.mcs[0].tbs;
   } else {
@@ -485,10 +489,11 @@ int srslte_ue_dl_ri_pmi_select(srslte_ue_dl_t *q, uint32_t *ri, uint32_t *pmi, f
     }
 
     /* Select the best Rank indicator (RI) and Precoding Matrix Indicator (PMI) */
-    for (uint32_t nof_layers = 1; nof_layers <= q->pdsch_cfg.nof_layers; nof_layers++ ) {
-      if (q->sinr[nof_layers][q->pmi[nof_layers]] > best_sinr + 0.1) {
-        best_sinr = q->sinr[nof_layers][q->pmi[nof_layers]]*nof_layers;
-        best_pmi = q->pmi[nof_layers];
+    for (uint32_t nof_layers = 1; nof_layers <= 2; nof_layers++) {
+      float _sinr = q->sinr[nof_layers - 1][q->pmi[nof_layers - 1]] * nof_layers;
+      if (_sinr > best_sinr + 0.1) {
+        best_sinr = _sinr;
+        best_pmi = q->pmi[nof_layers - 1];
         best_ri = nof_layers;
       }
     }