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wlan wifi

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WLAN (Wireless Local Area Network) and Wi-Fi.

  1. WLAN Basics:
    • A WLAN is a type of local area network that uses wireless communication to connect devices within a limited area such as a home, office, or campus.
    • It provides the same functionalities as a traditional wired LAN but eliminates the need for physical cables.
  2. Wi-Fi:
    • Wi-Fi, short for Wireless Fidelity, is a set of standards for wireless LAN communication.
    • The Wi-Fi standard is defined by the Institute of Electrical and Electronics Engineers (IEEE) under the 802.11 family of standards.
  3. Frequency Bands:
    • Wi-Fi operates in the 2.4 GHz and 5 GHz frequency bands.
    • 2.4 GHz provides better coverage but may suffer from interference, while 5 GHz offers higher data rates and is less crowded.
  4. Modulation and Data Rates:
    • Wi-Fi uses various modulation techniques to transmit data. Commonly used modulations include Quadrature Amplitude Modulation (QAM).
    • Higher-order QAM schemes allow for higher data rates. For example, 802.11ac supports up to 256-QAM.
  5. Channels:
    • Wi-Fi networks are divided into channels to avoid interference. In the 2.4 GHz band, there are 14 channels, while the 5 GHz band has more channels.
    • Adjacent channels must be separated to prevent interference. The channel width can vary, with 20 MHz and 40 MHz being common options.
  6. Access Points (APs):
    • An Access Point is a device that allows Wi-Fi devices to connect to a wired network using Wi-Fi.
    • Multiple access points can be used to create a Wi-Fi network with extended coverage, forming a Wireless Distribution System (WDS).
  7. Security:
    • Wi-Fi networks can be secured using encryption protocols such as WEP, WPA, and WPA2/WPA3.
    • WPA3 is the latest and most secure Wi-Fi security standard, offering enhanced protection against various attacks.
  8. Authentication and Association:
    • Devices need to authenticate with the Wi-Fi network using a pre-shared key or other authentication methods.
    • After authentication, a device associates with an access point to establish a connection.
  9. Multiple-Input Multiple-Output (MIMO):
    • MIMO technology uses multiple antennas for both the transmitter and receiver to improve communication performance.
    • It enables the use of spatial multiplexing, increasing data rates and reliability.
  10. Quality of Service (QoS):
    • QoS mechanisms prioritize certain types of data traffic, ensuring that time-sensitive applications like voice and video receive higher priority for smoother performance.
  11. Evolution of Wi-Fi Standards:
    • Wi-Fi standards have evolved over the years, with improvements in data rates, range, and efficiency. Examples include 802.11b, 802.11g, 802.11n, 802.11ac, and 802.11ax.