diff --git a/src/wifi/model/he/he-ppdu.cc b/src/wifi/model/he/he-ppdu.cc
index 5d2e17248..7e0747735 100644
--- a/src/wifi/model/he/he-ppdu.cc
+++ b/src/wifi/model/he/he-ppdu.cc
@@ -664,7 +664,7 @@ HePpdu::GetHeSigBContentChannels(const WifiTxVector& txVector, uint8_t p20Index)
     std::optional<HeSigBUserSpecificField> cc2Central26ToneRu;
 
     const auto& orderedMap = txVector.GetUserInfoMapOrderedByRus(p20Index);
-    std::optional<HeRu::RuType> prevRuType;
+    HeRu::RuType prevRuType{HeRu::RuType::RU_TYPE_MAX};
     std::size_t prevRuIndex{0};
     std::size_t prevCcIndex{0};
     for (const auto& [ru, staIds] : orderedMap)
@@ -688,9 +688,9 @@ HePpdu::GetHeSigBContentChannels(const WifiTxVector& txVector, uint8_t p20Index)
         }
 
         const auto ruIndex = ru.GetPhyIndex(channelWidth, p20Index);
-        if (prevRuType && (*prevRuType != ruType))
+        if ((prevRuType < HeRu::RuType::RU_TYPE_MAX) && (prevRuType != ruType))
         {
-            prevRuIndex *= HeRu::GetBandwidth(*prevRuType) / HeRu::GetBandwidth(ruType);
+            prevRuIndex *= HeRu::GetBandwidth(prevRuType) / HeRu::GetBandwidth(ruType);
         }
         if (ruType >= HeRu::RU_484_TONE)
         {
@@ -725,7 +725,7 @@ HePpdu::GetHeSigBContentChannels(const WifiTxVector& txVector, uint8_t p20Index)
             {
                 ccIndex = ((prevRuIndex / numRus) % 2 == 0) ? 0 : 1;
             }
-            const auto central26TonesRus = HeRu::GetCentral26TonesRus(channelWidth, *prevRuType);
+            const auto central26TonesRus = HeRu::GetCentral26TonesRus(channelWidth, prevRuType);
             const auto isCentral26ToneRu =
                 std::none_of(central26TonesRus.cbegin(),
                              central26TonesRus.cend(),
diff --git a/src/wifi/model/he/he-ru.h b/src/wifi/model/he/he-ru.h
index 62f4ec4ef..d73c7e389 100644
--- a/src/wifi/model/he/he-ru.h
+++ b/src/wifi/model/he/he-ru.h
@@ -36,7 +36,8 @@ class HeRu
         RU_242_TONE,
         RU_484_TONE,
         RU_996_TONE,
-        RU_2x996_TONE
+        RU_2x996_TONE,
+        RU_TYPE_MAX
     };
 
     /// (lowest index, highest index) pair defining a subcarrier range
diff --git a/src/wifi/model/spectrum-wifi-phy.cc b/src/wifi/model/spectrum-wifi-phy.cc
index 495a77141..dfcc6c75e 100644
--- a/src/wifi/model/spectrum-wifi-phy.cc
+++ b/src/wifi/model/spectrum-wifi-phy.cc
@@ -152,7 +152,7 @@ SpectrumWifiPhy::GetHeRuBands(Ptr<WifiSpectrumPhyInterface> spectrumPhyInterface
     {
         for (uint32_t i = 0; i < (channelWidth / bw); ++i)
         {
-            for (uint32_t type = 0; type < 7; type++)
+            for (uint32_t type = 0; type < HeRu::RuType::RU_TYPE_MAX; type++)
             {
                 auto ruType = static_cast<HeRu::RuType>(type);
                 std::size_t nRus = HeRu::GetNRus(bw, ruType);