The data processor 7, wherein the known data comprises {HEAD ~ the code} corresponding to {TAIL ~ a filler bit} 
corresponding to
The data processor 7 , wherein the known data comprises { HEAD ~ the code } corresponding to { TAIL ~ a filler bit }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL