The IEEE 802.11 family has continuously evolved since its first release in 1997. The initial 802.11-1997 standard supported only 1–2 Mbps in the 2.4 GHz band . In 1999, 802.11b improved this to 11 Mbps using DSSS/CCK modulation in the same band . That same year, 802.11a introduced operation in the 5 GHz band with OFDM modulation, reaching up to 54 Mbps .
By 2003, 802.11g brought OFDM to 2.4 GHz as well, matching 54 Mbps while maintaining backward compatibility with 802.11b . In 2009, 802.11n (later branded Wi-Fi 4) added significant upgrades such as 40 MHz channel bonding and MIMO with up to 4 spatial streams, boosting speeds to 600 Mbps in both 2.4 and 5 GHz bands .
802.11ac (Wi-Fi 5), finalized in 2013, focused solely on 5 GHz. It introduced wider channels (80/160 MHz), 256-QAM modulation, and MIMO up to 8×8, with downlink MU-MIMO support, reaching theoretical speeds of ~3.5 Gbps .
Then came 802.11ax (Wi-Fi 6), approved around 2020/2021, which shifted focus from raw speed to efficiency in dense environments. It supports 2.4 and 5 GHz (and 6 GHz via Wi-Fi 6E) , with speeds up to 9.6 Gbps. Its innovations include OFDMA, uplink/downlink MU-MIMO, BSS Coloring for interference reduction, and 1024-QAM .
Currently under development, 802.11be (Wi-Fi 7) is expected in 2024/2025. It promises theoretical speeds up to 40 Gbps with 320 MHz channels, 4096-QAM modulation, Multi-Link Operation (MLO), and expanded MIMO, aiming for ultra-low latency and superior multi-device performance .
802.11-1997: First Wi-Fi standard, 1–2 Mbps in 2.4 GHz .
802.11b (1999): 11 Mbps, 22 MHz channels at 2.4 GHz, DSSS/CCK modulation, longer range (~140 m outdoors) .
802.11a (1999): 54 Mbps at 5 GHz, first to use OFDM (16–64-QAM), 23 non-overlapping 20 MHz channels .
802.11g (2003): 54 Mbps at 2.4 GHz, OFDM, backward compatible with b .
802.11n (2009, Wi-Fi 4): Up to 600 Mbps in 2.4/5 GHz, MIMO (4 streams), 40 MHz channels .
802.11ac (2013, Wi-Fi 5): ~3.5 Gbps in 5 GHz, 80/160 MHz channels, 256-QAM, 8×8 MIMO, downlink MU-MIMO .
802.11ax (2020, Wi-Fi 6): 9.6 Gbps in 2.4/5 GHz (and 6 GHz in Wi-Fi 6E), OFDMA, bi-directional MU-MIMO, BSS Coloring, Target Wake Time (TWT) for power savings .
802.11be (Wi-Fi 7, in progress): Target 40 Gbps, 320 MHz channels, 4096-QAM (20% more efficient than 1024-QAM), Multi-Link Operation, up to 16 spatial streams, MRU (multi-RU) enhancements .
802.11ah (Wi-Fi HaLow, 2017): Designed for IoT, sub-1 GHz operation (~900 MHz), long range (up to 1 km), low power, thousands of devices supported, speeds up to ~347 Mbps with 16 MHz channel & 4 streams .
802.11-1997: 2.4 GHz .
802.11b/g: 2.4 GHz only .
802.11a/ac: 5 GHz only .
802.11n: 2.4 and 5 GHz .
802.11ax (Wi-Fi 6): 2.4 and 5 GHz; extended to 6 GHz via Wi-Fi 6E .
802.11be (Wi-Fi 7): 2.4, 5, and 6 GHz .
802.11ah (HaLow): Sub-1 GHz (~900 MHz) .
The original 802.11 used WEP (Wired Equivalent Privacy) in 1997, but it was quickly found insecure . In 2003, WPA was introduced as an interim fix, using TKIP key mixing and MIC integrity checks .
By 2004, WPA2 (IEEE 802.11i) became mandatory, switching to AES-CCMP encryption for robust security .
In 2018, WPA3 was launched:
Replaced PSK with SAE (Simultaneous Authentication of Equals), providing forward secrecy.
Introduced AES-GCM with 192-bit security in enterprise mode.
Added OWE for encrypting open networks.
Phased out TKIP completely .
By July 2020, WPA3 support became mandatory for Wi-Fi certification .
802.11-1997/802.11b: Main focus was providing faster wireless connectivity compared to wired. But interference in 2.4 GHz from household devices was a problem, leading to 5 GHz adoption in 802.11a .
802.11a: Targeted higher speeds and less interference at 5 GHz, though with reduced range due to higher frequency .
802.11g: Solved compatibility/cost by merging 802.11a’s speed with 802.11b’s 2.4 GHz ecosystem .
802.11n: Made Wi-Fi a true Ethernet alternative, with MIMO and dual-band support .
802.11ac: Answered demand for HD video and gigabit speeds with wider channels and MU-MIMO (downlink) .
802.11ax (Wi-Fi 6): Solved dense-network inefficiency via OFDMA, MU-MIMO, and BSS Coloring .
802.11be (Wi-Fi 7): Aims to support AR/VR, 8K streaming, and ultra-low latency gaming with 40 Gbps, 320 MHz channels, 4096-QAM, and MLO .
802.11ah (HaLow): Solved IoT challenges of range, power efficiency, and high device count by using sub-1 GHz spectrum .
Wi-Fi 7 (802.11be) is expected by 2024/2025. It will deliver 320 MHz channels, 4096-QAM (20% boost over Wi-Fi 6), and Multi-Link Operation across 2.4/5/6 GHz simultaneously . It also features preamble puncturing to use partial channels even in interference. This enables up to 20–40 Gbps throughput, ultra-low latency, and scalability for hundreds of devices .
Wi-Fi HaLow (802.11ah), finalized in 2017, targets IoT. Operating at ~900 MHz, it provides kilometer-range, wall penetration, and ultra-low power consumption. It supports thousands of devices, making it ideal for smart cities, agriculture, and industry .
Overall, Wi-Fi standards have continuously adapted to demand: from modest 2 Mbps speeds in 1997 to multi-gigabit, multi-band, and IoT-focused technologies today. The upcoming Wi-Fi 8 (802.11bn) is under early study, with goals of reliability and AI-driven network management .
This comprehensive report explores the evolution of Wi-Fi technologies from the first 802.11 standard to the latest Wi-Fi 7 and Wi-Fi HaLow. Discover the key features of each generation, frequency bands, speed and security improvements, and future applications of wireless networks.
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