3. Consider a wireless LAN with an access point and 10 stations (station 1, station 2, station 3, ..., and station 10). There is no hidden station in the network. At time instant 0 microsecond, the channel becomes idle, and station 1 and station 2 (each with one and only one DATA frame to be sent to the access point) start to contend for channel access, while other stations (including the access point) do not have data to send. The backoff timers of station 1 and station 2 are 10 and 30, respectively. How long is the duration from time instant 0 microsecond to the time instant when the first successful transmission starts (i.e., when the corresponding transmitter sends the first bit of its RTS)? How long is the duration from the time instant when the first successful transmission starts to the time instant when the second successful transmission starts? Assume DIFS=50 microseconds; SIFS=10 microseconds; a backoff time slot=20 microseconds; RTS transmission time=CTS transmission time=ACK transmission time=100 microseconds; A DATA frame transmission time = 800 microseconds. (10 points) 3. Consider a wireless LAN with an access point and 10 stations (station 1, station 2, station 3, ..., and station 10). There is no hidden station in the network. At time instant 0 microsecond, the channel becomes idle, and station 1 and station 2 (each with one and only one DATA frame to be sent to the access point) start to contend for channel access, while other stations (including the access point) do not have data to send. The backoff timers of station 1 and station 2 are 10 and 30, respectively. How long is the duration from time instant 0 microsecond to the time instant when the first successful transmission starts (i.e., when the corresponding transmitter sends the first bit of its RTS)? How long is the duration from the time instant when the first successful transmission starts to the time instant when the second successful transmission starts? Assume DIFS=50 microseconds; SIFS=10 microseconds; a backoff time slot=20 microseconds; RTS transmission time=CTS transmission time=ACK transmission time=100 microseconds; A DATA frame transmission time = 800 microseconds. (10 points)