From 5d9d5f6e67248060fb20f253ac81e6831cfd3b3d Mon Sep 17 00:00:00 2001
From: Klaus Kuehnhammer <klaus@bitstem.com>
Date: Tue, 3 Oct 2023 21:58:24 +0200
Subject: [PATCH] Support for PDCCH format 4 with 16 CCEs

---
 .gitignore                        | 63 +++++++++++++++++++++++++++++++
 lib/include/srsran/phy/ue/ue_dl.h |  3 +-
 lib/src/phy/phch/dci.c            |  2 +-
 lib/src/phy/phch/pdcch.c          |  2 +-
 lib/src/phy/ue/ue_dl.c            |  2 +-
 5 files changed, 68 insertions(+), 4 deletions(-)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000..9487d8a205
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,63 @@
+# Doxygen output
+docs
+
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# cmake build directory
+build
+cmake-build-debug
+
+# VIM files
+# Swap
+[._]*.s[a-v][a-z]
+!*.svg  # comment out if you don't need vector files
+[._]*.sw[a-p]
+[._]s[a-rt-v][a-z]
+[._]ss[a-gi-z]
+[._]sw[a-p]
+
+# Session
+Session.vim
+Sessionx.vim
+
+# Temporary
+.netrwhist
+*~
+# Auto-generated tag files
+tags
+# Persistent undo
+[._]*.un~
+
+#Clion
+.idea
diff --git a/lib/include/srsran/phy/ue/ue_dl.h b/lib/include/srsran/phy/ue/ue_dl.h
index 48f63d7666..2673f0c482 100644
--- a/lib/include/srsran/phy/ue/ue_dl.h
+++ b/lib/include/srsran/phy/ue/ue_dl.h
@@ -57,7 +57,8 @@
 #include "srsran/config.h"
 
 #define SRSRAN_MAX_CANDIDATES_UE 16 // From 36.213 Table 9.1.1-1
-#define SRSRAN_MAX_CANDIDATES_COM 6 // From 36.213 Table 9.1.1-1
+#define SRSRAN_MAX_CANDIDATES_COM 7 // From 36.213 Table 9.1.1-1
+                                    // 6 + 1: In addition to applying the procedures described in this Subclause for determining PDCCH assignment for non-MBSFN subframes on a MBMS-dedicated cell to receive MBMS on that cell when configured by higher layers, the UE shall also monitor a common search space ( L ) k S at aggregation level L=16 with a single PDCCH candidate M(L) =1 and Yk set to 0.
 #define SRSRAN_MAX_CANDIDATES (SRSRAN_MAX_CANDIDATES_UE + SRSRAN_MAX_CANDIDATES_COM)
 
 #define SRSRAN_MAX_FORMATS 4
diff --git a/lib/src/phy/phch/dci.c b/lib/src/phy/phch/dci.c
index 39a716b7f2..9ba8c1240a 100644
--- a/lib/src/phy/phch/dci.c
+++ b/lib/src/phy/phch/dci.c
@@ -1441,7 +1441,7 @@ int srsran_dci_location_set(srsran_dci_location_t* c, uint32_t L, uint32_t nCCE)
 
 bool srsran_dci_location_isvalid(srsran_dci_location_t* c)
 {
-  if (c->L <= 3 && c->ncce <= 87) {
+  if (c->L <= 4 && c->ncce <= 87) {
     return true;
   } else {
     return false;
diff --git a/lib/src/phy/phch/pdcch.c b/lib/src/phy/phch/pdcch.c
index 0272b20e8a..7b0bb09043 100644
--- a/lib/src/phy/phch/pdcch.c
+++ b/lib/src/phy/phch/pdcch.c
@@ -308,7 +308,7 @@ uint32_t srsran_pdcch_common_locations_ncce(uint32_t nof_cce, srsran_dci_locatio
   uint32_t i, l, L, k;
 
   k = 0;
-  for (l = 2; l <= 3; l++) {
+  for (l = 2; l <= 4; l++) {
     L = (1 << l);
     for (i = 0; i < SRSRAN_MIN(nof_cce, 16) / (L); i++) {
       // Simplified expression, derived from:
diff --git a/lib/src/phy/ue/ue_dl.c b/lib/src/phy/ue/ue_dl.c
index 1622d4a090..762e4b7d3f 100644
--- a/lib/src/phy/ue/ue_dl.c
+++ b/lib/src/phy/ue/ue_dl.c
@@ -460,7 +460,7 @@ static int dci_blind_search(srsran_ue_dl_t*     q,
 {
   uint32_t nof_dci = 0;
   if (rnti) {
-    for (int l = 0; l < search_space->nof_locations; l++) {
+    for (int l = search_space->nof_locations - 1; l >= 0; l--) {
       if (nof_dci >= SRSRAN_MAX_DCI_MSG) {
         ERROR("Can't store more DCIs in buffer");
         return nof_dci;