diff --git a/lib/decode_mac.cc b/lib/decode_mac.cc
index a792b7c..3f64cfd 100644
--- a/lib/decode_mac.cc
+++ b/lib/decode_mac.cc
@@ -162,8 +162,8 @@ public:
     {
 
         int n_cbps = d_ofdm.n_cbps;
-        int first[n_cbps];
-        int second[n_cbps];
+        int first[MAX_BITS_PER_SYM];
+        int second[MAX_BITS_PER_SYM];
         int s = std::max(d_ofdm.n_bpsc / 2, 1);
 
         for (int j = 0; j < n_cbps; j++) {
diff --git a/lib/utils.cc b/lib/utils.cc
index 0561ff7..952d1c0 100644
--- a/lib/utils.cc
+++ b/lib/utils.cc
@@ -224,8 +224,8 @@ void interleave(
 {
 
     int n_cbps = ofdm.n_cbps;
-    int first[n_cbps];
-    int second[n_cbps];
+    int first[MAX_BITS_PER_SYM];
+    int second[MAX_BITS_PER_SYM];
     int s = std::max(ofdm.n_bpsc / 2, 1);
 
     for (int j = 0; j < n_cbps; j++) {
diff --git a/lib/utils.h b/lib/utils.h
index f769eed..d1481b8 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -28,7 +28,8 @@ using gr::ieee802_11::Encoding;
 #define MAX_PAYLOAD_SIZE 1500
 #define MAX_PSDU_SIZE (MAX_PAYLOAD_SIZE + 28) // MAC, CRC
 #define MAX_SYM (((16 + 8 * MAX_PSDU_SIZE + 6) / 24) + 1)
-#define MAX_ENCODED_BITS ((16 + 8 * MAX_PSDU_SIZE + 6) * 2 + 288)
+#define MAX_BITS_PER_SYM 288
+#define MAX_ENCODED_BITS ((16 + 8 * MAX_PSDU_SIZE + 6) * 2 + MAX_BITS_PER_SYM)
 
 #define dout d_debug&& std::cout
 #define mylog(msg)                      \