The message passing {TAIL ~ decoder} 8, wherein {HEAD ~ the LDPC codes} have a fixed column weight 
The message passing { TAIL ~ decoder } 8 , wherein { HEAD ~ the LDPC codes } have a fixed column weight
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH