Wireless Data Networks, TLEN 5520/ECEN 5032Homework #1M. Heusse, Spring 2009Due in class: january 231 ARQWe consider a wireless channel with a CRC error detection: the sender adds to thepackets (typically) 4 bytes that are effectively a signature of the packet content. Thereceiver does the same computation and thus checks that the packets is not corrupt.If there is no error, the receiver replies with an acknowledgment packet. Thesender will re-send the frame if it does not get an ACK or if the ACK is corrupt.We consider a simple AWGN channel with a bit error probability PBER.1. What is the probability that a packet (resp. ACK) is received with error(s):Ppkterr(resp. Packerr).2. What is the probability PP Eto receive a single corrupt packet and falsely acceptit (so the CRC still matches the packet content, by chance)?3. What are the probability of having a successful exchange (Psucc) and the prob-ability that there is a retransmission (PEE), because the sender considers thatthe exchange failed?4. How many attempts are made for each frame, on average?5. What is the probability that a corrupt frame is accepted, after several at-tempts?6. What is the probability of experiencing more than Nmaxattempts for a givenframe?7. Setting Packerr= 0, plot the probability of successfully sending a frame in lessthan 10 attempts as a function of Ppkterr. Comments?12 First steps with linux and wireless LANYou should have a working linux install at hand now! Make your WLAN card work,this may require a little more effort after the installation! (If your card is Atheros,you may have to install the madwifi driver.)1. Install wireshark2. Associate to the campus wireless network, register your computer.3. Capture packets in promiscuous and monitor mode (not necessarily traffic thatyou generate yourself). What is the difference between these two
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