Overview
This lecture covers the evolution of small wireless networks, focusing on major Wi-Fi standards, frequency bands, and factors affecting network performance and reliability.
Wireless Networking Standards
- The IEEE 802.11 standards define wireless network protocols, including speed, frequency, and range.
- 802.11n (Wi-Fi 4) supports both 2.4 GHz and 5 GHz bands with speeds up to 600 Mbps and uses MIMO technology.
- 802.11ac (Wi-Fi 5) operates mainly on 5 GHz, supports up to 3.5 Gbps, and introduces MU-MIMO for simultaneous device data delivery.
- 802.11ax (Wi-Fi 6) increases speeds up to 9.6 Gbps, uses OFDMA for efficient multi-device management, and supports 2.4, 5, and 6 GHz bands.
- Wi-Fi 6E extends Wi-Fi 6 features to the 6 GHz band for more bandwidth and less interference.
Factors Affecting Performance
- Speed improves with newer standards: Wi-Fi 4 (600 Mbps), Wi-Fi 5 (3.5 Gbps), Wi-Fi 6 (9.6 Gbps), but actual speeds may be less due to interference or congestion.
- Interference occurs when multiple devices share a frequency (e.g., microwaves and Bluetooth use 2.4 GHz).
- Attenuation is signal weakening, increased by distance and obstacles; higher frequencies (5/6 GHz) have shorter range and are more attenuated.
Wireless Frequency Bands
- 2.4 GHz: Longer range, penetrates walls, but slower and more crowded.
- 5 GHz: Faster, less interference, shorter range.
- 6 GHz: Fastest, lowest interference, shortest range, and supported by Wi-Fi 6E.
Comparison: Older vs. Newer Standards
- Older standards (802.11a/b/g) had lower speeds (max 54 Mbps) and single-band operation.
- Newer standards (n/ac/ax) offer dual/triple-band, faster speeds, better device handling, and more efficient spectrum use.
- Modern standards like Wi-Fi 5/6 are recommended for future-proof, high-performance networks.
Key Terms & Definitions
- 802.11n (Wi-Fi 4) — Supports dual-band, up to 600 Mbps, uses MIMO.
- 802.11ac (Wi-Fi 5) — Operates on 5 GHz, up to 3.5 Gbps, uses MU-MIMO.
- 802.11ax (Wi-Fi 6) — Up to 9.6 Gbps, uses OFDMA, supports 2.4/5/6 GHz.
- MIMO — Multiple Input Multiple Output, uses multiple antennas for better performance.
- MU-MIMO — Multi-User MIMO, serves multiple devices at once.
- OFDMA — Orthogonal Frequency Division Multiple Access, enables efficient multi-device data sharing.
- Attenuation — Loss of signal strength over distance or through obstacles.
Action Items / Next Steps
- Review and memorize the differences between Wi-Fi 4, 5, and 6 standards.
- Know which frequency bands provide what advantages.
- Study for CompTIA Tech Plus exam focusing on wireless standards and network design.