zero-energy mtc
TRANSCRIPT
Zero-Energy MTC
© 2020 InterDigital, Inc. All Rights Reserved.1
Ravi Pragada
Sr. Director & Sr. Principal Engineer
Research & Innovation, InterDigital
Nov 11th, 2020
2 © 2020 InterDigital, Inc. All Rights Reserved.
Beyond 5G / 6G – Device proliferation challenge!
2G
100,000x vs.
GSM Phase 1
WCDMAHSPA
HSPA+LTE
LTE-A
2012+
GSM-EDGE
1990+
9.6 kbpsGSM Phase 1
Downlink Peak Data Rate
Spectral Efficiency
Carrier Bandwidth
Round Trip Latency
NR
240 kbps 384 Kbps 14 Mbps 42 Mbps 150 Mbps 1 Gbps 20 Gbps
0.17-0.33 bps/Hz 0.51 bps/Hz 2.9 bps/Hz 12.5 bps/Hz 16.3 bps/Hz 30 bps/Hz 40 bps/Hz
200 kHz 5 MHz 5 MHz 5 MHz Up to 20 MHz Up to 100 MHz 400 MHz
300 ms 250 ms ~70 ms ~40 ms ~30 ms ~20 ms ~1 ms
3G 4G 5GMillions of
voice users
Billions of mobile
broadband users100’s of Billions
of devices
Broadband Era … for the few
For B5G and 6G - a key challenge is to support up to 1 Trillion connected and mobile things
2,000,000x vs.
GSM Phase 1
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Challenges in Scaling to 1T Devices – Battery Capacity
❖ Less than a 10x improvement in battery
energy density from 1990 to 2015
compared to 105 &106 increase in storage
density and peak wireless data rate
❖ Assuming 1T devices with 10-year battery
life results in 274 million battery changes
per day
❖ For some future deployments battery
swapping will be difficult if not impossible
❖ Significant need to enable IoT device
operations that are less reliant on its
battery 1
10
100
1000
10000
100000
1990 1995 2000 2005 2010 2015
Gro
wth
Mu
ltip
les
Battery Energy Density
CPU Speed
DRAM Density
HDD Capacity
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Challenges in Scaling to 1T Devices – Latency vs Battery Life
❖ DRX & PSM based approaches in 3GPP MTC & NB-IoT suffer from an inherent
tradeoff between device reachability & battery life
❖ Longer DRX cycles result in extended battery life at the cost of latency
❖ Devices are not reachable during periods of deep sleep in PSM
❖ Furthermore, mobile devices must make periodic measurements thereby
limiting the maximum achievable battery life
How do we scale to 1T devices?
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Power-Save Enhancements in 3GPP to date
❖ There is a need to develop novel techniques in order to
❖ Break power-save latency vs battery life tradeoff and
❖ Eliminate the need to change battery throughout the useful life of the device
Zero-Energy Air-Interface - Overview
© 2020 InterDigital, Inc. All Rights Reserved.6
What is Zero-Energy Air-interface?
• An air interface that does not draw power from the IoT
device’s battery
• Addresses the Beyond 5G & 6G energy efficiency
challenges and today’s drawbacks in power
consumption versus DRX and PSM latency tradeoffs
How do we get there?
• Ultra-low power RF receivers capable of operating under
1uW budget
• Enable zero-energy radio operation with simultaneous
power and information delivery thereby facilitating battery-
less operation of devices
• A scalable system framework that can support a diverse set
of deployment scenarios with on-demand features
Zero-Energy (ZE) Receiver Arch
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ZE Receiver
• An ultra-low power receiver (ULP-RX) path used to decode information and
• An energy harvester path used to harvest energy
ULP-RX: Employs a rectification-first architecture consisting of
• A piezo-electric passive gain stage
• A multi-stage e.g. Dickson charge-pump rectifier
• An ultra-low power comparator and a set of ultra-low power correlators
Exemplary ZE Receiver Arch
Energy Harvester:
• Employs an impedance transformer followed by a rectifier and a large
capacitor for charge storage
• The output of the energy harvester is used to drive a boost type DC-to-
DC converter
• The output of the DC-to-DC converter is used to power the comparator
and the bank of correlators in the ULP-RX
Zero-Energy Air-Interface - Operation
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How does it work?
• Network transmits a power-optimized preamble (POP)
followed by higher layer data
• Devices use passive receiver to harvest energy from
the received in-band waveform and use it to run the
necessary circuitry to process received signals
• POP may be constructed using a single un-modulated
RF carrier or a multi-tone power optimized waveform
• The information sequence may be transmitted using
simple modulation techniques (e.g., Manchester-
encoded on-off keying)
• To ensure zero-energy operation the energy harvested
from the POP must be greater than that required to
decode the information in the body
Zero-Energy Air-Interface – On demand features
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On-demand Features
• Use the zero-energy (ZE) interface to introduce
on-demand features to the 3GPP system
framework
• Transmit on-demand wakeup signals that
deliver power and information on the ZE
interface
• Move mobility management related e.g. RSSI
measurements to the ZE interface
• Dynamically control the device’s UL
transmission repetition behavior using the ZE
interface
• Transfer wireless power to devices using the ZE
interface to compensate for the leakage
power of the device in deep sleep mode
Urban macro deployment with supplemental Zero-Energy Downlink (ZE-DL) for IoT devices
Proposed IoT device architecture with ZE Rx
Zero-Energy Air-Interface – Battery Life Impact
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Battery Life Comparison (PSM/DRX vs. ZE-WUS)
• In transaction cycle limited regime - Battery life of Type 2 UEs can still last for much longer
than Type 1 UEs
• For transaction cycles beyond 2 days - Battery life of Type 1 UE is limited by DRX cycle
whereas Type 2 UE’s battery life can reach a 35-40 year target!!
Estimated battery life of a mobile IoT device leveraging the
proposed WUS transmissions for wireless power delivery, on-
demand paging and RSSI measurements on the ZE-DL interface
Applications enabled by Zero-Energy Technology
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IoT, Wearables & other novel form-factors:
❖ Enable up to three-decade increase in battery life of IoT devices with sub-second network access latency as opposed to today’s long DRX cycle/paging latencies
❖ Huge value-add to Industrial IoT and other verticals such as asset monitoring, infrastructure monitoring, smart-cities, smart-transportation, smart oil & gas, etc. as well as connected home.
❖ Enables a host of new use-cases for Connected Home, enterprise IoT, smart-buildings, with “true wireless sensors” that go can go behind walls, embedded during construction, etc.
❖ Game changer for wearables and implants enabling new classes of devices allowing massive leaps in fluid interfaces such as smart-ring, wearables, etc.
High growth area with transformational impact and market opportunities
Infrastructure Monitoring
Asset MonitoringIndustrial IoT
Enterprise IoT
Connected Home Wearables / Battery-less Implants
12© 2020 InterDigital, Inc. All Rights Reserved.
Concluding Remarks
❖ Scaling to 1T devices will require us to re-imagine the radio transceiver, the air-interface and the overall system
❖ Not all IoT verticals are created equal – we will need to break through the power-save latency vs battery life tradeoffs in existing 3GPP duty-cycling approaches
❖ Need to develop Ultra-low power receivers that consume few 10s of nanowatt power and capable of macro-like link budgets
❖ On-demand features will have to be introduced to the cellular system framework using a new class of “zero-energy” air-interfaces that concurrently deliver power and information
❖ Using these PHY & MAC concepts a scalable system framework will have to be developed and integrated into future cellular networks!!