Lesson 3: Wi-Fi, Bluetooth, NFC, and RFID

Core path: 42 minutes

Wireless support is not just "check the bars." Different technologies use different ranges, purposes, frequencies, channels, and security models.

Wi-Fi bands

Recognize 2.4 GHz, 5 GHz, and 6 GHz Wi-Fi use.

General tradeoffs:

• 2.4 GHz can travel farther through obstacles but is crowded and offers fewer non-overlapping channel options;
• 5 GHz commonly offers more channels and higher throughput opportunities with shorter effective range;
• 6 GHz provides additional spectrum for supported Wi-Fi generations/devices but requires compatible clients/infrastructure.

Standards

Recognize common 802.11 generations such as Wi-Fi 5 (802.11ac), Wi-Fi 6/6E (802.11ax), Wi-Fi 7 (802.11be), plus legacy a/b/g/n support context.

Channels and widths

Channel selection depends on:

• frequency band;
• local regulatory rules;
• neighboring networks/interference;
• channel width;
• client/AP capability.

A wider channel can increase potential throughput while consuming more spectrum and increasing overlap risk.

Wi-Fi security

Use WPA2 with appropriate encryption or WPA3 where supported. Treat WEP and obsolete configurations as insecure legacy choices.

Bluetooth

Short-range personal-area connectivity for accessories and device-to-device functions. Pairing state, profiles, interference, battery, and OS support can all affect service.

NFC

Very short-range tap/proximity interaction used in payments, badges, pairing assistance, and other near-field workflows.

RFID

RFID uses radio-frequency tags/readers for identification/tracking workflows. Range and operation depend on the RFID technology/design. NFC is related but should not be treated as a synonym for every RFID system.

Guided case

A classroom puts every AP on a very wide overlapping channel because "wider is faster." Throughput drops during busy periods.

The configuration ignored spectrum reuse and neighboring interference.

Student action

Build a matrix for Wi-Fi, Bluetooth, NFC, and RFID:

primary purpose:
range class:
frequency/channel concern where applicable:
security/pairing concern:
one realistic support symptom:

Then design a 2.4/5/6 GHz AP strategy using supplied fictional neighboring-channel data.

Evidence checkpoint

Strong signal strength does not prove clean spectrum, correct security, healthy upstream connectivity, or compatible client capability.