Nano-Power Wireless Wake-Up Receiver With a Serial Peripheral Interface - Embedded.com

Nano-Power Wireless Wake-Up Receiver With a Serial Peripheral Interface

Wireless Body Area Networks have been a very popular area of research in recent years. The main research effort in this area focuses on reducing the communication power consumption of the WBAN sensors, as the radio transceiver is one of the highest power consumers.

Accordingly, several techniques have been proposed to minimize the transceiver’s duty cycle (the percentage of time during which it is in an active state). Whilst reducing the duty cycle helps to save power, it severely limits network flexibility.

The transceiver’s power consumption while listening idly on a channel can approach, or exceed, power consumption during data transmission. Therefore, if there is a need for asynchronous events to be initiated by the network coordinator, considerable energy must be spent by individual devices on idle listening.

To avoid wasting energy in this way, WBANs can benefit significantly from utilising an ultra- low-power wireless receiver which assumes responsibility for listening to identify asynchronous signals, thereby allowing the primary transceiver to be shut down.

We designed, implemented, tested and measured an ultra low power SPI-based Wake Up Receiver (WUR), intended for use in Wireless Body Area Networks (WBAN). Gaussian On- Off Keying (GOOK) and Pulse Width Modulation (PWM) are used to modulate and encode, respectively, the preamble signal.

The receiver incorporates a decoder to enable Serial Peripheral Interface (SPI). The WUR was also comprehensively tested for power consumption and robustness to RF interference from wireless de- vices commonly found in the vicinity of persons utilising WBAN technology.

Our results and comparative evaluation demonstrate that the achieved listening power of 270nW for the Wake Up Receiver is significantly lower power consumption than for the other state-of-the-art. The proposed preamble detection scheme can significantly reduce false wake ups due to other wireless devices in a WBAN. Additionally, SPI significantly reduces the overall power consumption for packet reception and decoding.

To read this external content in full, download the complete paper from the author archives at Euclidare.

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