As IoT proliferation continues, billions of connected sensors will transmit data from machines, industrial facilities, living spaces, wearables, and other environments creating an enormous demand for battery power. Across a wide range of different applications, system developers and infrastructure operators who need to support high volumes of sensor connectivity face the challenge of how to manage this in an efficient way. For wireless sensors, the implications of battery usage and waste management, as well as life-cycle maintenance costs are key concerns. HaiLa’s solution solves these IoT sensor deployment and maintenance challenges in a more sustainable way.
The BSC2000 RF Evaluation Chip is based on HaiLa’s passive backscatter technology, providing an extremely efficient, low-power communication link for battery-powered sensors. HaiLa’s technology significantly extends sensor battery life, reduces IoT deployment operating costs and battery waste, and offers a path towards ubiquitous ambient IoT in the future where sensor batteries could be eliminated altogether.
Additionally, HaiLa’s technology provides a way to extend the edge connectivity capabilities of Wi-Fi beyond the current protocol definitions and gives end-users lower total cost of ownership for wireless sensor deployment in a WLAN environment.
Passive backscatter explained
Passive backscatter is a communication technique where a device reflects or modulates an existing RF signal to transmit information. Unlike active RF communication, where a device generates its own RF signal, passive backscatter devices rely on ambient RF signals or signals transmitted by other sources. In wireless IoT devices, an antenna modulates an incident RF signal by reflecting (“scattering”) a portion of the incoming signal while introducing changes to its properties such as amplitude or frequency to encode new information on the signal. These changes are then detected and decoded by a receiver.
The BSC2000 is a complete system on chip containing all of the analog and digital baseband functions to enable collection of data from a sensor which can then be backscattered into a Wi-Fi signal. It can be integrated into a sensor tag together with an antenna, a sensor with a compatible SPI interface for sensor data communication, and supporting peripheral components including external memory and clocks. The BSC2000 operates in the 2.4GHz band covering all the channels defined in the 802.11b Wi-Fi specification where it performs codeword translations of 1Mbps DSSS symbols. In the Analog Front End (AFE), the envelope of the incoming RF signal is detected in the Envelope Detector, and the input data stream is backscattered by reflecting the incident RF wave through the RF switch (backscatter modulator).
There are three modes of operation for the BSC2000:
Standby mode: The envelope detector is switched on, the baseband processor is on standby, waiting for an infrastructure message, and the modulator is not backscattering.
Listening mode: The envelope detector is switched on, the baseband processor is decoding the infrastructure message, and the modulator is not backscattering.
Backscatter mode: The envelope detector is switched off, the baseband processor is encoding the sensor data, and the modulator is backscattering.
The baseband processor decodes the incoming data stream, retrieves the information from the target sensor connected to the BSC2000 via the SPI interface, and transfers the sensor data to the backscatter modulator. Device configuration is managed from an external flash memory via the SPI interface. The flash memory is powered down when not in use.