High Efficiency Rectifier for a Quasi-Passive Wakeup Radio

Abstract

The ubiquity of wireless sensor networks (WSN), as well as the rapid development of the Internet of Things (IoT), impel new approaches to reduce the energy consumption of the connected devices. The wake-up radio receivers (WuRx) were born in this context to reduce as much as possible the energy consumption of the radio communication part. This article aims at proposing a lowcost, high-efficiency rectifier to improve a quasi-passive WuRx performance in terms of communication range. By optimizing the wideband matching circuit and the proposed rectifier's load impedance, the sensitivity was increased by 5 dB, corresponding to an increase of the communication range (13 meters in free space). I.

Rural Healthcare IoT Architecture Based on Low-Energy LoRa

“…WuRx is a very low-power secondary radio that allows the main radio to remain powered off. As soon as some information should be transmitted, the WuRx receives a wake-up signal from the device initiating the communication and then decides to switch on the main radio receiver [ 52 ]. As a result, WuRx consumes power orders of magnitude lower than the radio hardware utilized by the wireless sensor [ 28 ].…”

“…In contrast, the duty cycle mode periodically activates the radio receiver, requiring the wake-up signal to be at least active for the receiver’s entire power cycle duration. When the communication is sporadic, this method is inefficient for energy consumption and latency, and it cannot be used for critical applications that require high-reliability [ 52 ]. The low duty cycle approach also suffers from network latency and the need for complex protocols to achieve synchronization while power is wasted during periods of no transmission [ 53 ].…”

“…To reach the ideal case of zero DC power consumption in standby mode, the passive wake-up receivers have been proposed [ 54 ]. Passive wake-up radios are those which are using the wake-up signal itself as the energy source [ 52 ]. They are also known as energy harvesting receivers because the wake-up signal is also powering the receiver, usually by charging a capacitor sufficient time to react to the signal.…”

“…This paper presents orthogonal frequency-division multiplexing (OFDM) transmitter which can generate an identifier without any additional hardware. When the identifier is sent as a frequency spectrum pattern, a simple analog circuit may be used for device selection [ 52 ].…”