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