This document discusses the design and operation of low-power wake-up receivers for wireless sensor networks. It describes how wake-up receivers can reduce the power consumption of sensor nodes by keeping transmitters and receivers in sleep mode until a wake-up signal is received. The document outlines the key components of wake-up receivers, including an envelope detector, baseband amplifier, and clock and data recovery circuit. It also summarizes research on implementing wake-up receivers using subthreshold CMOS circuits to achieve very low power consumption. Potential applications of wireless sensor networks using wake-up receivers include environmental monitoring, detecting oil leaks, and predicting drought conditions.

1. Riyas Ahammed C
Govt Model eng College, cochin
riyasahammedc@gmail.com
+91 9995574935
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2.  Used for Wireless Sensor Networks (WSN).
 WSN :- A set of sensor nodes deployed on a
specific location to gather intelligence.
 Challenges in WSN are
• Power
• Cost
• Communication protocol
• Size
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3.  Transmitter & Receiver consumes more power.
Ref : Design of an Ultra-Low Power Wake-Up Receiver: Master's Thesis
performed in Electronics systems, Fikre Tsigabu Gebreyohannes, 2012/06/12.
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4.  To reduce power we are using wake up
receivers.
 Txr & Rxr are in sleep mode or shut down
entirely.
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5.  WUR is an additional circuitary.
 Low power circuit.
 Active for extended period of time.
 Continuously listen to wireless channel.
 When a wake up signal is recieved it activates
other circuits.
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6.  Very low power consumption
 Minimise the false wake up signals
 Addressing Capability
 Flexibility and Usability
• Antenna and Frequency Re-use
• Use Existing Transmitter
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7.  An Envelope detector.
 High-gain baseband amplifier
 Clock and Data Recovery(CDR) circuit
 A wake up signal recognition circuit
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8.  A high-gain baseband amplifier with offset
canceller.
 An all-digital, clock and data recovery (CDR)
circuit.
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9. 9
Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida Masayuki
Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012

10. 10
Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida
Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012

11.  The feedback circuit consists of op amps.
 The input-/output- voltages are fixed to Vcm.
 The subthreshold op amps operate very slowly.
 The differential amplifier operates as a HP filter.
 Amp ouput has no DC offsets.
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12.  MOSFETs in the input stage are biased in the
subthreshold region.
 Envelope detection was performed with non-
linearity of drain current.
 M2 was used as driving MOSFET.
 M2 reduces 1/f noise.
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13.  The Id responds instantaneously to variation of
the gate- voltage VGS of the MOSFET M2.
 The high gain amplifier with this offset cancellation
circuit has no DC gain.
 Amplifies AC input signals.
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14. 14

15. 15
Ref : Low-power wake-up receiver with subthreshold CMOS circuits for
wireless sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki
Iida Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July
2012

16.  Three stage amplification is used.
 MOSFET M8 was used as a current mirror circuit.
 M8 determines the drain current of the drive
MOSFET (M2) in the detector.
 The VCM2 of the 3-stage Amp. was determined
by the ratio of the R3 and R4 resistors.
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17.  External resistors were used for R2–R4 to vary the
current in the gain stages and VCM2.
 The circuit performance is affected by variations
in fabrication parameters and ambient
temperature.
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18. 18
Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida
Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012

19.  When a wake-up signal arrives at the CDR,
 the turn- on detection circuit activates the ring OSC
 resets the counter
 transfers the content of the counter to the register.
 The ring oscillator frequency is at least four times
higher than the baseband frequency.
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20.  A 1-bit shifted value of the counted number is
transferred to the register.
 When the contents of the counter and the register
coincide with each other, the clock becomes ‘‘high.’’
 The clock turns on at the center position of the time
slot.
 At this moment, the data is read by using the clock
and a value of ‘‘1’’ or ‘‘0’’ is registered in the D–F/F.
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21.  When the wake-up signal stops and the counter
overflows, the ring oscillator is turned off.
 No exact relationship is required between the
oscillation frequency and the baseband frequency.
 It is an all-digital circuit.
 Average power consumption is almost 0.
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22.  Sensing of wildfires
 Drought prediction
 Sensing oil leakage
 Environmental Monitoring
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23.  Proposed wake up receiver operating in the
subthreshold region consumes only less
power.
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24.  Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida
Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July
2012.
 Design of an Ultra-Low Power Wake-Up Receiver: Master's Thesis
performed in Electronics systems, Fikre Tsigabu Gebreyohannes,
2012/06/12.
 Low Power Wake up Receiver for Wireless Sensor Networks: Vikas Kumar
and Rajender Kumar.Electronics & Comm. Engineering Deptt., National
Institute of Technology, Kurukshetra.
 www.wikipedia.com.
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25. THANK YOU
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