A feedback frame receiving apparatus for receiving a feedback frame transmitted by a receiver in response to a data frame transmitted by a transmitter, wherein said data frame transmitted by said transmitter and said {HEAD ~ feedback frame} transmitted by {TAIL ~ said receiver} have an identical format, said apparatus comprising: 
A feedback frame receiving apparatus for receiving a feedback frame transmitted by a receiver in response to a data frame transmitted by a transmitter , wherein said data frame transmitted by said transmitter and said { HEAD ~ feedback frame } transmitted by { TAIL ~ said receiver } have an identical format , said apparatus comprising :
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