# Bluetooth LE, Wi-Fi and 802.15.4

Common radios in home and wearable devices, and how each one trades range, speed and battery life.

Page: https://dharanova.com/learn/short-range-radio · Track: Talk · Level: Foundation · Facts last checked 6 October 2026

Diagram: Three rows. Bluetooth LE: the 2.4 GHz band as 40 channels 2 MHz apart, with the 3 primary advertising channels highlighted; three PHYs, LE 1M (the original), LE 2M (higher throughput) and LE Coded (longer range, 125 or 500 kbit/s), the last two added in Bluetooth 5.0; Core 6.0 (2024) added Channel Sounding. Wi-Fi: Wi-Fi 4 is 802.11n, 5 is 802.11ac, 6 is 802.11ax, 7 is 802.11be; with Target Wake Time a device sleeps and wakes to exchange data at times agreed with the access point; HaLow (802.11ah) runs below 1 GHz. IEEE 802.15.4: Zigbee and Thread use its 250 kbit/s radio at 2.4 GHz.

## Key points

1. Bluetooth Low Energy uses the 2.4 GHz band, divided into 40 channels 2 MHz apart; 3 of them are the primary advertising channels used for discovery. [1]
2. Bluetooth 5.0 added the LE 2M PHY for higher throughput and the LE Coded PHY (125 or 500 kbit/s) for longer range, alongside the original LE 1M PHY. [1][2]
3. Bluetooth Core 6.0, adopted in 2024, introduced Channel Sounding, which measures the distance between two devices using phase-based ranging and round-trip time. (as of 6 October 2026) [3][4]
4. Wi-Fi generation names map to IEEE standards: Wi-Fi 4 is 802.11n, Wi-Fi 5 is 802.11ac, Wi-Fi 6 is 802.11ax and Wi-Fi 7 is 802.11be. [5][6]
5. Target Wake Time lets a device agree with the access point when it will next wake to exchange data, so battery-powered clients can sleep longer. It was first defined for Wi-Fi HaLow (802.11ah) and Wi-Fi 6 brought it to mainstream Wi-Fi. [7][8]
6. Wi-Fi HaLow (802.11ah) runs below 1 GHz for longer range and better wall penetration at lower data rates; which sub-GHz frequencies it may use depends on each country's spectrum rules. [9][8][10]
7. IEEE 802.15.4 is a low-rate, low-power radio standard; in the 2.4 GHz band it carries 250 kbit/s. Zigbee and Thread are both built on it. [11][12][13]

## Where to go next

- [Mapping the Bluetooth stack](https://dharanova.com/mapping-the-bluetooth-stack.md): an engineering note from our team
- [Device-to-app sync for VAHA: architecture, and the integrity and security of the current build](https://dharanova.com/whitepapers/vaha-device-to-app-sync-integrity-security.md): a whitepaper from our lab
- [BLE application-layer authentication with ECDSA certificate chains on ESP32-C3](https://dharanova.com/whitepapers/ble-certificate-authentication.md): a whitepaper from our lab
- [LoRa, LoRaWAN, NB-IoT and LTE-M](https://dharanova.com/learn/long-range-radio.md): Low-power wide-area networks trade data rate for range and battery life. They suit small, infrequent messages from devices that sleep most of the time.
- [Matter, Thread and Zigbee](https://dharanova.com/learn/smart-home-standards.md): How smart-home devices from different brands are meant to work together, and which part of the job each standard covers.

## Sources

1. [Bluetooth Core Specification](https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core_v6.3/out/en/low-energy-controller/radio-physical-layer-specification.html), Bluetooth SIG
2. [Exploring Bluetooth 5: Going the distance](https://www.bluetooth.com/blog/exploring-bluetooth-5-going-the-distance/), Bluetooth SIG
3. [Bluetooth Core 6.0 feature overview](https://www.bluetooth.com/core-specification-6-feature-overview/), Bluetooth SIG
4. [Bluetooth SIG introduces true distance awareness](https://www.bluetooth.com/press/bluetooth-channel-sounding/), Bluetooth SIG
5. [Wi-Fi Alliance introduces Wi-Fi 6](https://www.wi-fi.org/news-events/newsroom/wi-fi-alliance-introduces-wi-fi-6), Wi-Fi Alliance
6. [Wi-Fi 7: Advanced connectivity for the next generation](https://www.wi-fi.org/beacon/the-beacon/wi-fi-7-advanced-connectivity-for-the-next-generation), Wi-Fi Alliance
7. [Wi-Fi CERTIFIED 6](https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6), Wi-Fi Alliance
8. [Wi-Fi CERTIFIED HaLow Technology Overview (Nov 2021)](https://www.wi-fi.org/system/files/Wi-Fi_CERTIFIED_HaLow_Technology_Overview_20211102.pdf), Wi-Fi Alliance
9. [Wi-Fi HaLow](https://www.wi-fi.org/discover-wi-fi/wi-fi-halow), Wi-Fi Alliance
10. [IEEE 802.11ah-2016: Sub 1 GHz License Exempt Operation](https://standards.ieee.org/ieee/802.11ah/4960/), IEEE
11. [IEEE 802.15.4: Low-Rate Wireless Networks](https://standards.ieee.org/ieee/802.15.4/11041/), IEEE
12. [Thread Network Fundamentals (May 2020)](https://www.threadgroup.org/Portals/0/documents/support/Thread%20Network%20Fundamentals_v3.pdf), Thread Group
13. [Matter FAQs](https://csa-iot.org/all-solutions/matter/matter-faq/), Connectivity Standards Alliance