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CWNA-109 · Question #42

You are evaluating access points for use in the 5 GHz frequency band. What PHY supports this band and supports 80 MHz channels?

The correct answer is B. VHT. VHT stands for Very High Throughput, which is a physical layer (PHY) specification that supports the 5 GHz frequency band and supports 80 MHz channels. VHT is used by the IEEE 802.11ac standard, which is also known as Wi-Fi 5. VHT allows for higher data rates and more spatial…

Wireless Standards and Organizations

Question

You are evaluating access points for use in the 5 GHz frequency band. What PHY supports this band and supports 80 MHz channels?

Options

  • AHT
  • BVHT
  • CERP
  • DOFDM

How the community answered

(43 responses)
  • A
    5% (2)
  • B
    91% (39)
  • C
    2% (1)
  • D
    2% (1)

Explanation

VHT stands for Very High Throughput, which is a physical layer (PHY) specification that supports the 5 GHz frequency band and supports 80 MHz channels. VHT is used by the IEEE 802.11ac standard, which is also known as Wi-Fi 5. VHT allows for higher data rates and more spatial streams than the previous HT (High Throughput) PHY, which is used by the IEEE 802.11n standard, also known as Wi-Fi 4. HT supports the 2.4 GHz and 5 GHz bands, but only supports up to 40 MHz channels The other options are not correct because: ERP (option C) stands for Extended Rate PHY, which is a physical layer specification that supports the 2.4 GHz frequency band and supports up to 20 MHz channels. ERP is used by the IEEE 802.11g standard, which is also known as Wi-Fi 3. ERP allows for higher data rates than the previous DSSS (Direct Sequence Spread Spectrum) PHY, which is used by the IEEE 802.11b standard, also known as Wi-Fi OFDM (option D) stands for Orthogonal Frequency Division Multiplexing, which is a modulation technique that divides a signal into multiple subcarriers that are spaced orthogonally to each other. OFDM is not a physical layer specification, but a common feature of many PHY specifications, including ERP, HT, and VHT. OFDM allows for higher spectral efficiency and robustness against multipath interference than the previous CCK (Complementary Code Keying) modulation technique used by DSSS.

Topics

#VHT#5 GHz band#80 MHz channels#802.11ac

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