--- a/src/devices/wimax/simple-ofdm-wimax-phy.cc	Tue Dec 28 22:25:20 2010 -0200
+++ b/src/devices/wimax/simple-ofdm-wimax-phy.cc	Tue Dec 28 18:37:09 2010 -0800
@@ -797,7 +797,7 @@
   m_nrBlocks = GetNrBlocks (burstSize, modulationType);
   m_paddingBits = (m_nrBlocks * m_blockSize) - (burstSize * 8);
   m_nrRemainingBlocksToSend = m_nrBlocks;
-  NS_ASSERT_MSG ((m_nrBlocks * m_blockSize) >= (burstSize * 8), "Size of padding bytes < 0");
+  NS_ASSERT_MSG (static_cast<uint32_t> (m_nrBlocks * m_blockSize) >= (burstSize * 8), "Size of padding bytes < 0");
 }
 
 uint16_t