4. The method as claimed in claim 2 , wherein said step (A) generates said discrimination result, on the basis of a frame size contained in a frame within said first code sequence.
4. The method as claimed in claim 2 , wherein said step (A) generates said discrimination result, on the basis of a frame size contained in a frame within said first code sequence. 5. The method as claimed in claim 4 , wherein said frame size is represented by a size of payload in this frame.