Why CDMA can make users communicate at the same time using the same frequency band without interference? Explain the advantages and disadvantages of CDMA. Why ADSL can achieve the transmission rate of...

Each question is a judgment question. Write down your answer with T for True, F for False, and give the explanation if the answer is False.

• Consider a system of bandwidth 10Mbps, with multiple users, each is active (i.e., have data to transmit at rate 1Mbps) with a low probability, e.g. 0.1. From the capacity perspective, packet switching is better than circuit switching because the former can support more users.


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  Denial of Service (DoS) attack can be generated by a large number of (legitimate) TCP connection requests to the same targeted server at the same time. These TCP requests can be originated from different hosts in a botnet, which is controlled by the attacker.

  
  


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  In VSAT systems the micro-stations do not have sufficient power to communicate directly with one another; hence, they use a ground station called a hub with a high gain antenna to relay traffic.

  
  


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  In the current Internet, communication across the Atlantic Ocean between the USA and Europe is mostly done by wireless communication using satellites.

  
  


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  Coaxial cable provides larger bandwidth than the twisted pair cable, and fiber provides larger bandwidth than the coaxial cable.