diff --git a/src/wifi/model/he/he-ppdu.cc b/src/wifi/model/he/he-ppdu.cc
index ef3d40531..f228ca4dc 100644
--- a/src/wifi/model/he/he-ppdu.cc
+++ b/src/wifi/model/he/he-ppdu.cc
@@ -217,6 +217,10 @@ HePpdu::SetHeMuUserInfos(WifiTxVector& txVector,
         auto ruAllocIndex = contentChannelIndex;
         for (const auto& userInfo : contentChannel)
         {
+            if (userInfo.staId == NO_USER_STA_ID)
+            {
+                continue;
+            }
             auto ruSpecs = HeRu::GetRuSpecs(ruAllocation.at(ruAllocIndex));
             if (ruSpecs.empty())
             {
diff --git a/src/wifi/model/wifi-tx-vector.cc b/src/wifi/model/wifi-tx-vector.cc
index 3c844eaa6..1260bc29d 100644
--- a/src/wifi/model/wifi-tx-vector.cc
+++ b/src/wifi/model/wifi-tx-vector.cc
@@ -688,22 +688,37 @@ WifiTxVector::GetContentChannels(uint8_t p20Index) const
             continue;
         }
 
-        size_t numRus{1};
-        if (ruType < HeRu::RU_242_TONE)
-        {
-            numRus = HeRu::m_heRuSubcarrierGroups.at({20, ruType}).size();
-        }
-
+        std::size_t numRus = (ruType >= HeRu::RU_242_TONE)
+                                 ? 1
+                                 : HeRu::m_heRuSubcarrierGroups.at({20, ruType}).size();
         if (((ruIdx - 1) / numRus) % 2 == 0)
         {
-            contentChannels[0].push_back({staId, userInfo.nss, userInfo.mcs});
+            contentChannels.at(0).push_back({staId, userInfo.nss, userInfo.mcs});
         }
         else
         {
-            contentChannels[1].push_back({staId, userInfo.nss, userInfo.mcs});
+            contentChannels.at(1).push_back({staId, userInfo.nss, userInfo.mcs});
         }
     }
 
+    // Add unassigned RUs
+    auto numNumRusPerHeSigBContentChannel =
+        HePpdu::GetNumRusPerHeSigBContentChannel(m_channelWidth, GetRuAllocation(p20Index));
+    std::size_t contentChannelIndex = 1;
+    for (auto& contentChannel : contentChannels)
+    {
+        const auto totalUsersInContentChannel = (contentChannelIndex == 1)
+                                                    ? numNumRusPerHeSigBContentChannel.first
+                                                    : numNumRusPerHeSigBContentChannel.second;
+        NS_ASSERT(contentChannel.size() <= totalUsersInContentChannel);
+        std::size_t unallocatedRus = totalUsersInContentChannel - contentChannel.size();
+        for (std::size_t i = 0; i < unallocatedRus; i++)
+        {
+            contentChannel.push_back({NO_USER_STA_ID, 0, 0});
+        }
+        contentChannelIndex++;
+    }
+
     return contentChannels;
 }