Bluetooth Low Energy Channels & Frequencies

The RF channels used for Bluetooth Low Energy, LE consist of Primary Advertising Channels and Data Channels / Secondary Advertising channels and they are ordered to avoid clashes with Wi-Fi.

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Bluetooth Low Energy, BLE uses the 2.4 GHz ISM, Industrial, Scientific and Medical band which does not require a transmitting licence for its use.

The actual Bluetooth LE frequency range extends from 2402 to 2480 MHz for the centre frequencies of the channels, and this means it utilises the whole of the internationally agreed 2.4GHz allocation.

The Bluetooth uses frequency hopping techniques, utilising the different Bluetooth LE channels which are all spaced 2 MHz apart in frequency from each other and this gives sufficient bandwidth to carry the BLE signals.

The concept of frequency hopping
The concept of frequency hopping

There is a total or 40 channels - less than the 79 used for Bluetooth Classic, but the frequency spacing for LE is wider - Bluetooth Classic has a 1 MHz bandwidth against Bluetooth LE which uses 2 MHz.

There are two types of channel, namely the Primary Advertising Channels and the Data Channels which can also be used as a Secondary Advertising Channel.

In order to avoid clashes with Wi-Fi the Primary Advertising channels, which are numbered 37, 38 and 39 are placed at frequencies of 2402 MHz, 2426, and 2480 MHz.

The reason for this is to avoid clashes with Wi-Fi and ensure that the advertising channels are not compromised.

However it does lead to the channel numbering looking a little out of order. The Data Channels are numbered from 0 to 36, and the advertising channels 37, 38, and 39. However they are not all arranged in frequency order because of the interference issues.

Bluetooth LE channels & frequencies list

A list of the Bluetooth Low Energy channel numbers, their frequencies and functions are given in the table below:

Bluetooth LE Channel Listing
 
Channel Frequency (MHz) Channel Number Channel Application
2402 37 P.Adv
2404 0 Data Ch
2406 1 Data Ch
2408 2 Data Ch
2410 3 Data Ch
2412 4 Data Ch
2414 5 Data Ch
2416 6 Data Ch
2418 7 Data Ch
2420 8 Data Ch
2422 9 Data Ch
2424 10 Data Ch
2426 38 P.Adv
2428 11 Data Ch
2430 12 Data Ch
2432 13 Data Ch
2434 14 Data Ch
2436 15 Data Ch
2438 16 Data Ch
2440 17 Data Ch
2442 18 Data Ch
2444 19 Data Ch
2446 20 Data Ch
2448 21 Data Ch
2450 22 Data Ch
2452 23 Data Ch
2454 24 Data Ch
2456 25 Data Ch
2458 26 Data Ch
2460 27 Data Ch
2462 28 Data Ch
2464 29 Data Ch
2466 30 Data Ch
2468 31 Data Ch
2470 32 Data Ch
2472 33 Data Ch
2474 34 Data Ch
2476 35 Data Ch
2478 36 Data Ch
2480 39 P.Adv

Where:
    P.Adv = Primary Advertising Channel
    Data Ch = Data Channel / Secondary Advertising Channel



The Bluetooth Low Energy system uses 40 channels which are different to those used for Bluetooth Classic with the channel centre frequencies ranging from 2402 MHz to 2480 MHz.

The way in which the channel numbers are selected and numbered with respect to the frequencies may seem a little counter-intuitive, but this results from the fact that the advertising channels need to remain clear of the interference that might be caused by nearby Wi-Fi routers and devices.


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