Understanding WiFi Standards: A Complete Guide


WiFi technology has come a long way since it first started. Each new standard has brought better speed, capacity, and reliability. Let's explore how WiFi standards have evolved and what makes each one unique through this image and understand some of the key Technology improvements offered by each Standard:




Legacy Standards (802.11 Legacy)

The journey began with the original IEEE 802.11 standard in 1997. This early version offered:


802.11-Prime (DSSS)

  • Data rates: 1 and 2 Mbps
  • Frequency band: 2.4 GHz
  • Modulation: FHSS (Frequency Hopping Spread Spectrum) or DSSS (Direct Sequence Spread Spectrum)

802.11b (1999) 

The first widely used WiFi standard brought big improvements:
  • Data rates: Up to 11 Mbps
  • Frequency band: 2.4 GHz
  • Modulation: DSSS
  • Range: Up to 100 meters indoors
  • Compatibility: Worked with the original 802.11 standard

802.11a (1999)

Released at the same time as 802.11b but with different features and the operational band:
  • Data rates: Up to 54 Mbps
  • Frequency band: 5 GHz
  • Modulation: OFDM (Orthogonal Frequency Division Multiplexing)
  • Interference: Less interference due to 5 GHz operation
  • Range: Shorter range compared to 802.11b 

802.11g (2003)

Combined the best of both worlds of 802.11b and 802.11g:
  • Data rates: Up to 54 Mbps
  • Frequency band: 2.4 GHz
  • Modulation: OFDM
  • Compatibility: Worked with 802.11b
  • Adoption: Widely adopted due to better speed and compatibility

802.11n (WiFi 4, 2009)

  • Technology: MIMO (Multiple Input Multiple Output)
  • Capability: Channel bonding
  • Data rates: Up to 600 Mbps
  • Operation: Dual-band (2.4 GHz and 5 GHz)
  • Compatibility: Worked with previous standards
  • Efficiency: Frame aggregation

802.11ac (WiFi 5, 2014)

  • Band: 5 GHz
  • Technology: MU-MIMO (Multi-User MIMO)
  • Channels: Wider channels (up to 160 MHz)
  • Modulation: Higher order modulation (up to 256-QAM)
  • Speeds: Theoretical speeds up to 3.5 Gbps

802.11ax (WiFi 6, 2019)

The latest major standard with revolutionary features: 
  • Technology: Extension of Wi-Fi 6 using the 6 GHz band with features like OFDMA, MU-MIMO, and 1024-QAM.
  • Bands: Operates on 2.4 GHz, 5 GHz, and the new 6 GHz band (5.925-7.125 GHz) providing additional 59, 20MHz channels.
  • Modulation: Supports 1024-QAM for higher data density and throughput.
  • Efficiency: Features like OFDMA, MU-MIMO, and TWT enhance multi-user efficiency and reduce interference.
  • Speeds: Theoretical speeds up to 9.6 Gbps, with real-world speeds typically 2-3 Gbps.

802.11ax (WiFi 6E, 2021)

In addition to WiFi6 features, such as 1024-QAM, Multi-User MIMO (MU-MIMO) and Orthogonal Frequency-Division Multiple Access (OFDMA), WiFi ^E introduced 
  • WiFi 6E introduced, new 6 GHz band, offering up to 1,200 MHz of additional spectrum.
  • Speeds: Theoretical speeds up to 9.6 Gbps

802.11be (WiFi 7, 2023)

The latest major standard with revolutionary features:
  • Technology:  Wi-Fi 7 introduces Multi-Link Operation (MLO), 4096-QAM,Enhanced MU-MIMO, Preamble Puncturing and Supports up to 16 spatial streams.
  • Bands: Operates on 2.4 GHz, 5 GHz, and 6 GHz bands, supports channels up to 320 MHz
  • Modulation: Supports 4096-QAM, offering 20% higher data rates compared to 1024-QAM in Wi-Fi 6.
  • Speeds: Theoretical speeds of up to 46 Gbps.

Key Technological Improvements Across 802.11 Standards and different generations:


Channel Width Evolution 
  • 802.11b/g: 20 MHz
  • 802.11n: 20/40 MHz
  • 802.11ac: 20/40/80/160 MHz
  • 802.11ax: 20/40/80/160 MHz 
  • 802.11be: 20/40/80/160/320 MHz with more efficient use
Modulation Advancements
  • Legacy: BPSK, QPSK
  • 802.11ac: Up to 256-QAM
  • 802.11ax: Up to 1024-QAM
  • 802.11be: Up to 4096-QAM
MIMO Development
  • 802.11n: Introduction of MIMO
  • 802.11ac: MU-MIMO (downlink only)
  • 802.11ax: MU-MIMO (uplink and downlink)
  • 802.11be: Enhanced MU-MIMO
Conclusion

WiFi standards keep evolving, bringing better speed, capacity, and efficiency with each generation. Understanding these standards is crucial for designing, implementing optimal wireless solutions and troubleshooting issues related to these aspects. WiFi 7 (802.11be) promise even more impressive capabilities, ensuring that wireless technology continues to meet growing connectivity demands.

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