Fix symbol size simensioning for LTE standard rate

lib/src/phy/common/phy_common_nr.c

@@ -194,6 +194,9 @@ uint32_t srsran_min_symbol_sz_rb(uint32_t nof_prb)
   const uint32_t* symbol_table = phy_common_nr_valid_symbol_sz;
   if (srsran_symbol_size_is_standard()) {
     symbol_table = phy_common_nr_valid_std_symbol_sz;
+
+    // Add extra RE to ensure a minimum guard band and prevent 100 RB use an FFT size of 1536
+    nof_re += (3 * nof_re) / 10;
   }
 
   for (uint32_t i = 0; i < PHY_COMMON_NR_NOF_VALID_SYMB_SZ; i++) {