The challenge with classic Bluetooth is fast battery drain and frequent connection drops, requiring frequent pairing and re-pairing. Being able to successfully solve these problems is one of the reasons for the rapid growth of BLE. Bluetooth Low Energy is the smarter, power-saving version of Bluetooth wireless technology. It’s already playing a major role in turning smart gadgets into smarter ones, making them compact, affordable and less complicated.
So how does BLE achieve low power consumption, and what are its technical characteristics? According to the information released by the SIG official press conference, compared with the classic BT technology, the main changes are mainly reflected in the reduction of standby power consumption, the realization of high-speed connection and the reduction of peak power consumption.
- Data transfer: BLE supports very short data packets (minimum 8 octets, maximum 27 octets) at 1 Mbps. All connections use advanced sniff-sub rating (deceleration sniff mode) to achieve ultra-low duty cycle, thereby minimizing power consumption.
- Frequency Hopping: BLE uses AFH common to all Bluetooth technology versions to minimize interference from other technologies in the 2.4 GHz ISM band. Efficient multipathing benefits increase link budget and effective operating range, and optimize energy consumption.
- Host – Controller: The radio frequency band and radio frequency turn-on time are reduced. Traditional Bluetooth uses 16 to 32 frequency bands for broadcasting, while BLE only uses 3 broadcast frequency bands. The radio frequency turn-on time for each broadcast is reduced from 22ms of traditional Bluetooth to 0.6~1.2ms, faster connection (discovery happens on 3 channels). BLE puts a lot of energy in the controller, which allows HOST to sleep for a longer time (Duty-Cycle), and is only woken up by the controller when HOST needs to perform certain operations, and in Duty-Cycle, the sending data interval is also controlled increase. This saves the most current since the host processor typically consumes more power than the BLE controller.
- More “loose” RF parameters and sending very short packets: Both technologies use Gaussian Frequency Shift Keying (GFSK) modulation, but Bluetooth Low Energy uses a modulation index of 0.5 compared to 0.35 for standard Bluetooth. 0.5 The exponent is close to the Gaussian minimum shift keying (GMSK) scheme, which can reduce the power consumption requirements of wireless devices. Meanwhile, Bluetooth low energy technology uses very short data packets — which keeps the silicon cool. Therefore, Bluetooth low energy transceivers do not require power-intensive recalibration and closed-loop architectures.
- Latency: Standard Bluetooth technology is a “connection-oriented” wireless technology with a fixed connection time interval, so it is ideal for high-activity connections such as mobile phones connecting wireless headsets. In contrast, BLE can support connection establishment and data transfer as fast as 3 milliseconds. This enables applications to establish a connection and transmit authenticated data in just a few milliseconds for brief communications before quickly disconnecting.
- Range: The increased modulation index allows the maximum range of BLE to exceed 100 meters.
- Robustness: BLE uses a strong 24-bit CRC on all packets to ensure maximum immunity to interference.
- Strong Security: Full AES-128 encryption using CCM provides strong packet encryption and authentication so communications are secure.
- Topology: BLE uses a 32-bit access address on every packet for every slave device, allowing billions of devices to be connected. The technology is optimized for one-to-one connections while allowing one-to-many connections using a star topology.
Chip-level support: The low-power mode of the chip is used to limit the power consumption of the chip. The chip provides a variety of low-power controls to reduce the power consumption of the chip.
- System working mode control: The entire SOC (System on a chip) system has multiple working modes, and different working modes can be selected according to actual power consumption requirements and performance requirements.
- Clock gating and clock frequency modulation: provide a clock shutdown function, which can turn off unnecessary clocks and reduce power consumption of the chip. The clock frequency of the system can be adjusted. After meeting the frequency reduction conditions of the whole system, the system can automatically switch the clock frequency to reduce the power consumption of the chip.
- Module-level low-power consumption control: Provide module-level low-power consumption control. When BLE or DSP is not working, the power of the module can be turned off to reduce the power consumption of the chip.
The Bluetooth low energy module developed by the MuYu team helps the BLE module achieve low power consumption by combining energy-saving design, lower data rate, optimized connection parameters and other technologies, making it suitable for various battery-powered and energy-responsive limited applications, such as wearable devices, IoT sensors, and other battery-powered devices.