Bluetooth Low Energy (LE)
Bluetooth Low Energy (LE), introduced with Bluetooth 4.0 in 2010, is a wireless communication protocol optimized for short-range, low-power data exchanges. Unlike Bluetooth Classic, LE is tailored for battery-powered devices and intermittent transmissions, making it ideal for wearables, sensors, and IoT applications.
Frequency & Modulation
Bluetooth LE operates in the 2.4 GHz ISM band, using 40 channels with 2 MHz spacing:
Data Channels: 37
Advertising Channels: 3
The modulation scheme is GFSK (Gaussian Frequency Shift Keying). Several physical layer (PHY) options are defined:
LE 1M PHY: 1 Mbit/s data rate (default)
LE 2M PHY: 2 Mbit/s for faster throughput
LE Coded PHY: 125 kbit/s (S=8) or 500 kbit/s (S=2) for extended range, using forward error correction (FEC)
These PHYs provide flexibility between speed and range, while maintaining energy efficiency.
Typical Applications
Bluetooth LE is used in applications that require minimal power consumption and short, burst-type communication:
Health & Fitness: Heart rate monitors, temperature sensors, fitness trackers
Industrial & Smart Home: BLE beacons, occupancy sensors, lighting control
Peripherals: BLE HID for keyboards and mice
Broadcasting: Beaconing and extended advertising (Bluetooth 5 and later)
The main protocol used for data exchange is the Generic Attribute Profile (GATT), enabling structured communication via predefined services and characteristics.
Differences from Bluetooth Classic
Compared to BR/EDR, Bluetooth LE offers:
Significantly lower power consumption
Optimized connection procedures and sleep modes
No support for legacy profiles like A2DP or SPP
Native support for one-to-many advertising and GATT-based services
While LE does not match Bluetooth Classic in continuous data throughput, it excels in efficient short exchanges.
Relevance for Testing & Certification
Bluetooth LE devices must comply with regional radio requirements. The key approval paths are listed below.
| Region / Authority | Approval Path |
|---|---|
| EU (CE / RED) | EN 300 328 (Self-Declaration) |
| USA (FCC) | FCC §15.247 via TCB |
| Canada (ISED) | RSS-247 + IC ID |
| Brazil (ANATEL) | ANATEL SRD |
| Japan (MIC / Telec) | MIC / Telec Certification |
| China (SRRC) | SRRC / CMIIT-ID |
| Region / Authority | Approval Path |
|---|---|
| EU (CE / RED) | EN 300 328 (Self-Declaration) |
| USA (FCC) | FCC §15.247 via TCB |
| Canada (ISED) | RSS-247 + IC ID |
| Brazil (ANATEL) | ANATEL SRD |
| Japan (MIC / Telec) | MIC / Telec Certification |
| China (SRRC) | SRRC / CMIIT-ID |
Although Bluetooth LE operates in the same 2.4 GHz band as Bluetooth Classic, its channel structure, timing behavior, and PHY characteristics require separate evaluation during regulatory testing.
In addition to regulatory approval, Bluetooth SIG Qualification is mandatory for any product using Bluetooth technology and intended to use the Bluetooth name or logo. The qualification covers protocol, interoperability, and listing requirements and can be completed only by registered SIG members.