Adaptive Sampling Receiver for IoT Energy Efficiency

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Solution Overview

Problem

Existing short-range wireless receivers face challenges in achieving high energy efficiency due to their high power consumption, which is critical for miniaturized smart sensors in IoT applications that require battery lifetime of 10+ years or batteryless operation, especially when sensitivity is traded off for power reduction.

Innovation Solution

A fully integrated 2.4 GHz receiver with an RF front-end, analog-to-digital converter, and digital baseband processor that adapts sampling and processing rates based on link quality, reducing power consumption by lowering sampling rates when link quality is high, while maintaining compatibility with IEEE 802.15.4 packets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the sampling rate is reduced to lower power consumption, then energy efficiency is improved, but sensitivity and link reliability deteriorate

Engineering Contradiction:
Improvepower consumptionVSAvoidlink reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The receiver dynamically adjusts the sampling rate based on real-time link quality conditions. When link quality is good, the sampling rate is reduced to save power; when link quality degrades, the sampling rate is increased to maintain reliability. This dynamic adaptation resolves the contradiction between power consumption and link reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the sampling rate parameter according to link quality metrics. By monitoring link conditions and adjusting the sampling rate parameter accordingly, the system achieves energy efficiency under good conditions while maintaining sensitivity and reliability when conditions deteriorate.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If the sampling rate is reduced to extend battery life, then duration of operation is improved, but measurement precision and detection capability worsen

Engineering Contradiction:
Improvebattery lifeVSAvoidsignal detection precision
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The receiver employs dynamic sampling rate adjustment where the sampling rate is changed based on link quality assessments. During periods of good link quality, lower sampling rates extend battery life while maintaining adequate detection precision. When link quality degrades, the system increases sampling rates to preserve signal detection precision, thus resolving the contradiction between battery life and measurement precision.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If adaptive sampling is implemented to reduce power consumption, then energy efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidprocessing complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The adaptive sampling process is segmented into distinct functional blocks: link quality assessment module, sampling rate determination module, and variable rate sampling module. This segmentation manages complexity by organizing the adaptive sampling function into modular, manageable components with clear interfaces between them.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary link quality assessment before adjusting sampling rates. By evaluating link conditions in advance and determining appropriate sampling rates beforehand, the system reduces the complexity of real-time decision-making during signal processing.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9444515B2Short-range zigbee compatible receiver with near-threshold digital baseband
Publication Date: 2016.09.13 THE RGT UNIV OF MICHIGAN
  • US9444515B2 patent drawing
  • US9444515B2 patent drawing
  • US9444515B2 patent drawing

AI summary

An 8.1 nJ/bit 2.4 GHz receiver with integrated digital baseband supporting Q-QPSK DSSS modulation compliant with the IEEE 802.15.4 standard is presented that targets short-range, Internet of Things applications (IoTs). The sensitivity of a wireless communication receiver in general trades with power consumption. This receiver exploits this tradeoff to achieve a total power consumption of 2.02 mW including ADCs and digital baseband processing, at a sensitivity of −52.5 dBm at 250 Kbps. The energy-efficiency of the radio frequency (RF) front-end alone is nearly two times better than the prior art. The receiver was fabricated in 65 nm CMOS with an area of 0.86 mm2.