(6) For the figure (2), WLAN in ad-hoc network mode where stations A, B and C are within the range of each other, while stations A and D are within the range of each other. A starts its transmission to D at time slot (t = 33). Assume 802.11 CSMA with ACK; slot time = 1; backoff interval (rB, rC) = (6, 4); SIFS = 1; ACK = 1; DIFS = 3 and the data frame is 4 slots. Answer the following questions: a) At what time will station A finish its transmission? b) Assume that at slot time (t = 35), B has a frame ready to be transmitted to A. At what slot time will B be able to start its transmission? c) Assume that at slot time (t = 40), B has a frame ready to be transmitted to A. At what slot time will B be able to start its transmission? d) If B has a frame ready to be transmitted to A at (t = 35). Assume that at slot time (t = 37), C has a frame ready to be transmitted to A. At what slot time will C be able to start its transmission? Why no collision expected between the transmission of B and C? e) Based on part (d); assume that at slot time (t = 53), D has a frame ready to be transmitted to A. At what slot time will D be able to start its transmission? Does this frame collide with another frame?

Figure (2) Figure (2)