Wireless¶
| Generation / Standard | Technical Name | PHY Mode (Full Name) | Release Year | Key Bands | Max Speed (2.4 GHz) | Max Speed (Total / Main) | Best Used For / Notes |
|---|---|---|---|---|---|---|---|
| Legacy | IEEE 802.11a | OFDM | 1999 | 5 GHz | N/A (5 GHz only) | 54 Mbit/s | Early enterprise 5 GHz Wi-Fi |
| Legacy | IEEE 802.11b | DSSS/HR-DSSS | 1999 | 2.4 GHz | Single band | 11 Mbit/s | Early mainstream consumer Wi-Fi |
| Legacy | IEEE 802.11g | ERP-OFDM | 2003 | 2.4 GHz | Single band | 54 Mbit/s | Mid-2000s standard home networks |
| WiMAX | IEEE 802.16 | WirelessMAN | 2004 | 2–11 GHz | N/A (Non-Wi-Fi protocol) | 70 Mbit/s | Early fixed/mobile broadband wireless |
| Wi-Fi 4 | IEEE 802.11n | High Throughput | 2009 | 2.4 GHz, 5 GHz | 150–600 Mbit/s | 600 Mbit/s | Basic browsing, smart home devices |
| WiGig | IEEE 802.11ad | Directional Multi-Gigabit | 2011 | 60 GHz | N/A (60 GHz only) | 7.14–7.2 Gbit/s | Ultra-short-range multi-gigabit line-of-sight |
| Wi-Fi 5 | IEEE 802.11ac | Very High Throughput | 2012 | 5 GHz | N/A (Uses 802.11n on 2.4G) | 6.8–6.93 Gbit/s | HD streaming, moderate home networks |
| Wi-Fi 6 | IEEE 802.11ax | High Efficiency | 2019 | 2.4 GHz, 5 GHz | ~287x4 Mbit/s | ~9.6 Gbit/s | High-density smart homes & public spaces |
| Wi-Fi 6E | IEEE 802.11ax | High Efficiency | 2021 | 2.4 GHz, 5 GHz, 6 GHz | ~1,148 Mbit/s | ~9.6 Gbit/s | Low-interference 6 GHz connectivity |
| Wi-Fi 7 | IEEE 802.11be | Extremely High Throughput | 2024 | 2.4 GHz, 5 GHz, 6 GHz | ~1,376 Mbit/s (4096-QAM) | ~46 Gbit/s | 4K/8K streaming, AR/VR, ultra-low latency |
Modulation and Coding Scheme¶
Dynamic MCS Adaptation: Wi-Fi constantly monitors signal quality and shifts MCS up or down in real time - Close to the Router (High SNR): The device selects a high MCS index
| Generation | Standard | PHY Mode | MCS Index Range | Highest Modulation | Highest Coding Rate | Max Spatial Streams | Max Channel Width |
|---|---|---|---|---|---|---|---|
| Wi-Fi 4 | 802.11n | HT | 0–31 (0–7 per stream) | 64-QAM | 5/6 | 4 | 40 MHz |
| Wi-Fi 5 | 802.11ac | VHT | 0–9 | 256-QAM | 5/6 | 8 | 160 MHz |
| Wi-Fi 6 / 6E | 802.11ax | HE | 0–11 | 1024-QAM | 5/6 | 8 | 160 MHz |
| Wi-Fi 7 | 802.11be | EHT | 0–15 (0–13 main) | 4096-QAM (4K-QAM) | 5/6 | 16 | 320 MHz |
Key Takeaways:
- Higher QAM = More Data Density: BPSK/QPSK transfers 1–2 bits per symbol, 64-QAM transfers 6 bits, 256-QAM transfers 8 bits, 1024-QAM transfers 10 bits, and 4096-QAM transfers 12 bits.
- SNR Requirement: Higher MCS numbers require a cleaner, stronger signal (higher Signal-to-Noise Ratio). If interference occurs, the device automatically drops to a lower MCS index to prevent packet loss.