Lecture Notes: 802.11 Wireless Networks and Bluetooth

Key Concepts of 802.11 Networks

• Frequency Bands:
  • 2.4 GHz and 5 GHz Bands:
    • Various 802.11 standards use these frequency ranges.
    • Some standards can utilize both ranges for communication.
• Channels:
  • Within the frequency ranges, there are specific channels.
  • IEEE assigns numbers to these channels for easier identification.
  • Important to use different channels for multiple access points in the same area to avoid interference.

Regulatory Considerations

• Government Regulations:
  • Different countries/regions have specific regulations for wireless spectra.
  • Regulations may include:
    • Permitted frequencies.
    • Maximum power usage.
    • Interference limits.

Comparison of 2.4 GHz and 5 GHz Networks

• 2.4 GHz Networks:
  • Common channels: 1, 6, and 11.
  • Bandwidth: 20 MHz ranging from 2412 MHz to 2482 MHz.
  • Limited to three non-overlapping channels, leading to congestion in dense areas like apartment complexes.
• 5 GHz Networks:
  • Offer more channels than 2.4 GHz.
  • Support for larger bandwidths (20 MHz, 40 MHz, 80 MHz, 160 MHz).
  • 160 MHz channels require non-contiguous areas for operation.

Bluetooth Technology

• Usage:
  • Commonly used for wireless peripherals (headsets, speakers, keyboards).
  • Operates in the 2.4 GHz ISM band, which is unlicensed and freely usable.
• Personal Area Network:
  • Typical range: 10 meters for consumer devices.
  • Industrial Bluetooth can extend range beyond 100 meters.

Summary

• 802.11 networks primarily operate on 2.4 GHz and 5 GHz frequencies, with various channels within these ranges.
• Governmental regulations impact the usage and limitations of these networks.
• The 5 GHz spectrum offers more flexibility and bandwidth options compared to 2.4 GHz, which is often congested.
• Bluetooth operates on a part of the 2.4 GHz band and is used for short-distance communication, typically around 10 meters for consumer devices.