A subtracter subtracts the estimated wraparound speech signal ai d′ from {HEAD ~ the input speech signal “bi}” to generate {TAIL ~ an echo cancellation signal “ei}” 
A subtracter subtracts the estimated wraparound speech signal ai d′ from { HEAD ~ the input speech signal “ bi } ” to generate { TAIL ~ an echo cancellation signal “ ei } ”
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH