diff --git a/lib/frame_equalizer_impl.cc b/lib/frame_equalizer_impl.cc
index 97a1a53..dbe7288 100644
--- a/lib/frame_equalizer_impl.cc
+++ b/lib/frame_equalizer_impl.cc
@@ -337,7 +337,7 @@ frame_equalizer_impl::parse_signal(uint8_t *decoded_bits) {
 	return true;
 }
 
-int
+const int
 frame_equalizer_impl::interleaver_pattern[48] = {
 	 0, 3, 6, 9,12,15,18,21,
 	24,27,30,33,36,39,42,45,
diff --git a/lib/frame_equalizer_impl.h b/lib/frame_equalizer_impl.h
index 86ea4dc..e5f9e65 100644
--- a/lib/frame_equalizer_impl.h
+++ b/lib/frame_equalizer_impl.h
@@ -79,7 +79,7 @@ private:
 	constellation_16qam::sptr d_16qam;
 	constellation_64qam::sptr d_64qam;
 
-	static int interleaver_pattern[48];
+	static const int interleaver_pattern[48];
 };
 
 } // namespace ieee802_11