MAC Protocols & Multiple Access Methods : MCQs & PYQs with Explanation

Option D

IEEE 802.11ac is a wireless networking standard used in Wi-Fi technology that operates primarily in the 5 GHz frequency band. It provides higher data rates, better bandwidth, and less interference compared to older standards like 802.11n.
It is commonly known as Wi-Fi 5 and supports advanced features like MIMO (Multiple Input Multiple Output) and wider channel bandwidth.

Option D

The statement (I) is true, CDMA spreads the signal over the entire available spectrum using spread-spectrum technology.
The statement (II) is true, every user has a unique pseudo-random code, which allows multiple users to share the same frequency simultaneously.
The statement (III) is false, CDMA technology offers more security compared to GSM because it uses spread spectrum technology and encryption, making signal interception and detection harder. 
The statement (IV) is false, A SIM card is not always required for CDMA devices. CDMA phones traditionally do not rely on SIM cards, unlike GSM phones.

Option C

In computer networks, multiple devices share a common communication medium. To avoid conflicts when two devices try to transmit simultaneously, access control mechanisms are used. These mechanisms can be Collision-Prone or Collision-Free:

• Collision-prone protocols allow the possibility that two devices transmit at the same time, causing a collision, and then require retransmission. ALOHA,  CSMA/CD, CSMA/CA are example of collision-prone protocols.
• Collision-free protocols use a structured approach to ensure only one device transmits at a time, preventing collisions entirely. Token Passing (Token Ring or Token Bus) is collision-free mechanism, only the station holding the token may transmit, so concurrent transmissions cannot occur.