From 1a6e5cdee5f52451c85221b08e10b82865c99848 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier@softwareradiosystems.com>
Date: Fri, 9 Apr 2021 18:18:26 +0200
Subject: [PATCH] Demodulator sets LLR to zero for 0.0 symbols

---
 lib/src/phy/modem/demod_soft.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/src/phy/modem/demod_soft.c b/lib/src/phy/modem/demod_soft.c
index dac7a5f09..a81bf1eaf 100644
--- a/lib/src/phy/modem/demod_soft.c
+++ b/lib/src/phy/modem/demod_soft.c
@@ -928,5 +928,15 @@ int srsran_demod_soft_demodulate_b(srsran_mod_t modulation, const cf_t* symbols,
       ERROR("Invalid modulation %d", modulation);
       return -1;
   }
+
+  uint32_t nof_bits_x_symbol = srsran_mod_bits_x_symbol(modulation);
+  for (uint32_t i = 0; i < nsymbols; i++) {
+    if (!isnormal(__real__ symbols[i]) || !isnormal(__imag__ symbols[i])) {
+      for (uint32_t j = 0; j < nof_bits_x_symbol; j++) {
+        llr[i * nof_bits_x_symbol + j] = 0;
+      }
+    }
+  }
+
   return 0;
 }