diff --git a/DataFormats/ForwardDetId/src/HGCEEDetId.cc b/DataFormats/ForwardDetId/src/HGCEEDetId.cc
index 9b2613c8cc483..43fb8452f6201 100644
--- a/DataFormats/ForwardDetId/src/HGCEEDetId.cc
+++ b/DataFormats/ForwardDetId/src/HGCEEDetId.cc
@@ -15,6 +15,7 @@ HGCEEDetId::HGCEEDetId(ForwardSubdetector subdet, int zp, int lay, int sec, int
 
   id_ |= ((cell   & 0xfff) << 0 );
   id_ |= ((sec    & 0x3f)  << 12);
+  if(subsec<0) subsec=0;
   id_ |= ((subsec & 0x1)   << 18);
   id_ |= ((lay    & 0x1f)  << 19);
   if (zp>0) id_ |= ((zp & 0x1) << 24);
diff --git a/DataFormats/ForwardDetId/src/HGCHEDetId.cc b/DataFormats/ForwardDetId/src/HGCHEDetId.cc
index b6b6ecd89aaf8..cd67894355058 100644
--- a/DataFormats/ForwardDetId/src/HGCHEDetId.cc
+++ b/DataFormats/ForwardDetId/src/HGCHEDetId.cc
@@ -14,6 +14,7 @@ HGCHEDetId::HGCHEDetId(ForwardSubdetector subdet, int zp, int lay, int sec, int
 
   id_ |= ((cell   & 0xfff) << 0 );
   id_ |= ((sec    & 0x3f)  << 12);
+  if(subsec<0) subsec=0;
   id_ |= ((subsec & 0x1)   << 18);
   id_ |= ((lay    & 0x1f)  << 19);
   if(zp>0) id_ |= ((zp & 0x1) << 24);
diff --git a/DataFormats/ForwardDetId/src/HGCalDetId.cc b/DataFormats/ForwardDetId/src/HGCalDetId.cc
index d31119232b7ad..cfaac6eeae4e9 100644
--- a/DataFormats/ForwardDetId/src/HGCalDetId.cc
+++ b/DataFormats/ForwardDetId/src/HGCalDetId.cc
@@ -25,6 +25,7 @@ HGCalDetId::HGCalDetId(ForwardSubdetector subdet, int zp, int lay, int sec, int
   uint32_t rawid=0;
   rawid |= ((cell   & 0xffff) << 0 );
   rawid |= ((sec    & 0x7f)   << 16);
+  if(subsec<0) subsec=0;
   rawid |= ((subsec & 0x1)    << 23);
   rawid |= ((lay    & 0x7f)   << 24);
   if (zp>0) rawid |= ((zp     & 0x1)    << 31);
diff --git a/SimCalorimetry/HGCSimProducers/interface/HGCDigitizer.h b/SimCalorimetry/HGCSimProducers/interface/HGCDigitizer.h
index dafa46dd78fa9..c9f2bb22041b5 100644
--- a/SimCalorimetry/HGCSimProducers/interface/HGCDigitizer.h
+++ b/SimCalorimetry/HGCSimProducers/interface/HGCDigitizer.h
@@ -57,6 +57,9 @@ class HGCDigitizer
 
 private :
 
+  //used for initialization
+  bool checkValidDetIds_;
+
   //input/output names
   std::string hitCollection_,digiCollection_;
 
diff --git a/SimCalorimetry/HGCSimProducers/interface/HGCDigitizerBase.h b/SimCalorimetry/HGCSimProducers/interface/HGCDigitizerBase.h
index 35bd482c0f88a..7169fa18a8149 100644
--- a/SimCalorimetry/HGCSimProducers/interface/HGCDigitizerBase.h
+++ b/SimCalorimetry/HGCSimProducers/interface/HGCDigitizerBase.h
@@ -57,7 +57,6 @@ class HGCDigitizerBase {
 	it!=simData.end();
 	it++)
       {
-
 	//convert total energy GeV->keV->ADC counts
 	double totalEn(0);
 	for(size_t i=0; i<it->second.size(); i++) totalEn+= (it->second)[i];
@@ -76,8 +75,6 @@ class HGCDigitizerBase {
 
 	if(singleSample.adc()==0) continue;
 	
-	//std::cout << totalEn << " -> Gain:" << singleSample.gain() << " #ADC:" << singleSample.adc() << std::endl;
-	
 	//no time information
 	D newDataFrame( it->first );
 	newDataFrame.setSample(0, singleSample);
diff --git a/SimCalorimetry/HGCSimProducers/src/HGCDigitizer.cc b/SimCalorimetry/HGCSimProducers/src/HGCDigitizer.cc
index 3b3e607981994..6d3e44999d6c0 100644
--- a/SimCalorimetry/HGCSimProducers/src/HGCDigitizer.cc
+++ b/SimCalorimetry/HGCSimProducers/src/HGCDigitizer.cc
@@ -16,6 +16,7 @@
 
 //
 HGCDigitizer::HGCDigitizer(const edm::ParameterSet& ps) :
+  checkValidDetIds_(true),
   theHGCEEDigitizer_(ps),
   theHGCHEbackDigitizer_(ps),
   theHGCHEfrontDigitizer_(ps),
@@ -45,7 +46,7 @@ HGCDigitizer::HGCDigitizer(const edm::ParameterSet& ps) :
 }
 
 //
-void HGCDigitizer::initializeEvent(edm::Event const& e, edm::EventSetup const& es)
+void HGCDigitizer::initializeEvent(edm::Event const& e, edm::EventSetup const& es) 
 {
   resetSimHitDataAccumulator(); 
 }
@@ -165,6 +166,22 @@ void HGCDigitizer::accumulate(edm::Handle<edm::PCaloHitContainer> const &hits, i
       if(itime<0 || itime>(int)simHitIt->second.size()) continue;
       (simHitIt->second)[itime] += ien;
     }
+  
+  //add base data for noise simulation
+  if(!checkValidDetIds_) return;
+  if(!geom.isValid()) return;
+  HGCSimHitData baseData(10,0);
+  const std::vector<DetId> &validIds=geom->getValidDetIds(); 
+  int nadded(0);
+  for(std::vector<DetId>::const_iterator it=validIds.begin(); it!=validIds.end(); it++)
+    {
+      uint32_t id(it->rawId());
+      if(simHitAccumulator_.find(id)!=simHitAccumulator_.end()) continue;
+      simHitAccumulator_[id]=baseData;
+      nadded++;
+    }
+  std::cout << "Added " << nadded << " detIds without " << hitCollection_ << " in first event processed" << std::endl;
+  checkValidDetIds_=false;
 }
 
 //
diff --git a/SimGeneral/MixingModule/python/hgcalDigitizer_cfi.py b/SimGeneral/MixingModule/python/hgcalDigitizer_cfi.py
index ca1b93ac02f74..8a9185ddaff47 100644
--- a/SimGeneral/MixingModule/python/hgcalDigitizer_cfi.py
+++ b/SimGeneral/MixingModule/python/hgcalDigitizer_cfi.py
@@ -24,9 +24,9 @@
 hgchebackDigitizer = hgceeDigitizer.clone()
 hgchebackDigitizer.hitCollection = cms.untracked.string("HGCHitsHEback")
 hgchebackDigitizer.digiCollection = cms.untracked.string("HGCDigisHEback")
-hgchefrontDigitizer.digiCfg.mipInKeV = cms.untracked.double(1498.4)
-hgchefrontDigitizer.digiCfg.lsbInMIP = cms.untracked.double(0.25)
-hgchefrontDigitizer.digiCfg.mip2noise = cms.untracked.double(5.0)
+hgchebackDigitizer.digiCfg.mipInKeV = cms.untracked.double(1498.4)
+hgchebackDigitizer.digiCfg.lsbInMIP = cms.untracked.double(0.25)
+hgchebackDigitizer.digiCfg.mip2noise = cms.untracked.double(5.0)