{TAIL ~ A communications channel} comprises a buffer that receives {HEAD ~ user data} that includes a plurality of m bit symbols 
{ TAIL ~ A communications channel } comprises a buffer that receives { HEAD ~ user data } that includes a plurality of m bit symbols
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH