4.2Wireless LAN and mobile

A network designer introducing wireless LAN into an office or factory cannot simply "pick the newest standard"—they must combine the standard, frequency band, channel design, and authentication method to optimize for concrete conditions such as the number of users, device density, sources of radio interference, and security requirements. This section builds the judgment needed to decide what wireless environment design is appropriate, grounded in the characteristics of wireless LAN standards and mobile communication.

4.2.1IEEE 802.11 standards and Wi-Fi 6

• The IEEE 802.11 standards have grown faster and more efficient generation by generation: 802.11a/g (max 54 Mbps) -> 802.11n (adopts MIMO, max 600 Mbps) -> 802.11ac (5 GHz band, MU-MIMO, multi-Gbps) -> 802.11ax (Wi-Fi 6) (2.4/5 GHz bands, adopts OFDMA, dramatically improving simultaneous-connection efficiency for many devices).
• The core advantage of Wi-Fi 6 (802.11ax) is not simply a higher peak rate but improved efficiency when many devices connect simultaneously, achieved via OFDMA (orthogonal frequency-division multiple access). By dividing a single channel into multiple resource units (RUs) and assigning them to several devices at once, it shows its true value in dense environments such as offices or stadiums packed with IoT devices and smartphones. Wi-Fi 6E extends this into the 6 GHz band, providing access to clean spectrum that avoids the congested 2.4/5 GHz bands.