Thus, any occurrence of {HEAD ~ a combination} of {TAIL ~ sequences} that causes large interference may reduce the communications quality 
of
Thus , any occurrence of { HEAD ~ a combination } of { TAIL ~ sequences } that causes large interference may reduce the communications quality
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH