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L'optimisation des consommations de puissance
IRCICA
19 Juin 2018
Challenges in a very dynamic and demanding market environment
Power Consumption Analysis with CMW/RTO 2
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Power Consumption Analysis with CMW/RTO
Up to10 years battery life?
3
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It‘s all about connecting everything – wireless & cordlessbattery
Battery
capacity
5 Ah
0 Ah
10 Ah
15 Ah
101100 102 103 104 105
Day Week Month Year 10 years
High demand for cordless IoT devices using energy storage and/or harvesting technologies
• Battery is a cost factor: • Battery costs depend on
capacity
• Cost of battery replacement
• Design for replacement
• In some cases the battery lifetime defines the lifetime of the device
m3
P
Smart meter
Park sensor
Plant monitor
Container tracking
Phone
66
Watch Health monitor
Battery lifetime in hours
Power Consumption Analysis with CMW/RTO 4
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The low-power design challenge
• Low power architecture
• Low power components
• Sleep power minimization
• Active power optimization
• …..
Low-power hardware design
• Operating system
• Communication protocol
• Operational model
• Maintenance model (upgrade)
• ……
Low-power software design
Low-power wireless communication
LP-PAN
Bluetooth, …
LP-LAN
Wi-Fi HaLow, .., ZigBee, Thread, ..
LP-WAN
Sigfox, LoRa, …LTE Cat M1/NB1…
Considering/modelling all relevant aspects impacting power consumption
Power Consumption Analysis with CMW/RTO 5
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Basic principles to realize low power communication networks
Streamlined signaling
• Minimize the necessary signaling (e.g. resume connections, connectionless)
• Optimize communication (e.g. IP header compression)
Receiver optimization
• Implement application for an
uplink-only communication
• Minimize time spend in
receiving mode
Efficient transmission
• Apply reliable communication (lower order modulation, repetitions, frequency hoping)
• Use power efficient transmission modes (single tone transmission)
• Functional limitations
• Responsiveness
• Quality of service
• Security
• Delay
• Data rate (power)
Power Consumption Analysis with CMW/RTO 6
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3GPP ecosystem is addressing the LP-WAN market as well
LTE Cat M1 NB-IoT (Cat NB1)
DeploymentIn-band LTE
In-band LTE
Guard-band LTE
Standalone
Downlink OFDMA [15 kHz] OFDMA [15 kHz]
UplinkSC-FDMA [15 kHz]
Single-tone [15/3.75 kHz]
SC-FDMA [15 kHz]
Peak rate DL: 1 Mbps
UL: 1 Mbps
DL: 250 kbps
UL: 20 kbps (ST)
UE receiver BW 1.4 MHz 200 kHz
UE TX power 23 or 20 dBm 23 or 20 dBm
Power saving PSM, eDRX PSM, eDRX
Power Consumption Analysis with CMW/RTO 7
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Optimized RRC signaling
CIoT-Uu
Optimized network architecture to minimize signaling efforts
MME
HSS
S-GW
SCEF
App
App
P-GW
T6a
S5
S1-U
S1-MMEMME
SMS
GW
REST API
IPv4/v6
CIoTBS
UE
Non-IP messages via C-plane
IP messages via C-plane
IP/non-IP messages via User Plane
Data transmission over control plane
Power Consumption Analysis with CMW/RTO 8
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Power Saving Mode (PSM) for deep sleep operation
activ
e
Tx
activ
e
I-DRX (<2.56 s) TAU
T3324
T3412…; 54 min;....; 310 hours; … Send data
Pow
er c
onsu
mpt
ion
PSM ModeIdle
UE remains registered with the network and there is no need to re-attach or re-establish
PDN connections – saves power, but UE isn’t reachable in PSM Mode
Attach / TAU Request
(T3324, T3412 ext. value)
Attach / TAU Accept
(T3324, T3412 ext. value)
RRC Connection Release
PSM Mode [T3412]
Idle Mode [ T3324]
MMEUE1 eNB
Power Consumption Analysis with CMW/RTO
Tx
Rx
sleep
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Extended discontinuous reception (eDRX) to save power
activ
e
Tx
activ
e
eMTC: 5.12 s; 10.24 s … 2621.44 sSend data
I-eDRX I-eDRX I-eDRX I-eDRX
Idle Mode
Pow
er c
onsu
mpt
ion
Energy consumption can be reduced significantly with longer cycles for discontinuous
reception (DRX), if certain degree of mobile terminating services reachability is acceptable.
Attach / TAU Request
(Extended DRX parameters)
Attach / TAU Accept
(Extended DRX parameters)
Idle Mode
MMEUE1 eNBExample: extended DRX in Idle Mode
NB-IoT: 20.48 s; 40.96 s … 10 486.76 s
RRC Connection Release
Power Consumption Analysis with CMW/RTO 10
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It becomes more complex to optimize the power consumption
Extended DRX(Idle Mode)
UE power class
UE categoryPower saving mode (PSM)
Coverage enhancement
Conditions
Data exchange architecture
Cat NB1
Cat M1
Cat 0
Cat 1
20 dBm
23 dBm
U-Plane
Non-IP
IP
5.12 s
10.24 s
43.69* min
6 min
12 min
310 h
Level 0
Level 1
Level 2
Design decision Negotiation w/ network
* eDRX timer for eMTC; for NB-IoT up to 175 min
Power Consumption Analysis with CMW/RTO
14 dBm
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Need for precise power measurements and detailed views
on all relevant aspects under reproducible network conditions
IoT
app.
MME
S-GW
SCEF
P-GW
MMECIoTBSDUTPMIC LTE
µP
GPIO1.8 V
3.3 V
2.8 V
• Communication behavior
• Timer (eDRX, PSM)
• Power modes
V
I
• Feature support (PSM,…)
• Coverage conditions
• Communication modes
• Throughput
• Delay, jitter
• Loss
• Communication behavior
• Device triggering
• Maintenance actions
• Power monitoring and analysis of whole system incl. battery, without specific power supply and on multiple channels
• Very high dynamic range and high time resolution of I, V and P measurements
• Possibility to correlate with signaling/network events
Power Consumption Analysis with CMW/RTO 12
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The demo test setup
Power Consumption Analysis with CMW/RTO
3.8V
RF
The evaluation board drives the module per USB, which
needs power.
Additional components (LEDs) needs also power.
Other interface, e.g. USB to COM converter needs power.
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The functions of the instruments and DUT
Power Consumption Analysis with CMW/RTO
Voltage(V)
Current(I)
Power = V x I
Tx signal at antenna
3.8V
RF
System emulator for Cat-M1
network
Message logging
DL/UL power control
Power Save Mode
Paging cycle and eDRX
connected/idle
…
DUT is configured by AT
commands before attach
DUT is tested without additional
interface (USB, COM)
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Multi-channel power probe designed for large range measurements
Power Consumption Analysis with CMW/RTO 15
l Digital control of range, amplification/attenuation
l Input voltage range: ±15 V to GND (CM + differential), not floating
l Variable gain and attenuation in the same signal path
R&S®RT-ZVCxxAHigh dynamic range, 18bit resolution
3 internal shunts and external shunt
1MHz bandwidth, 5Msample/s
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Auto-Ranging for High-Dynamic Current Sensing
Power Consumption Analysis with CMW/RTO 16
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Instead a power supply, this setup is using a real 3.8V lithium
battery
Power Consumption Analysis with CMW/RTO
3.8V
GND
RF
Analyse the embedded system incl. battery is
more close to the reality.
As key part of the whole embedded system,
the battery has impact on the power
consumption behaviour.
The internal resistance of batteries is a non-
LTI (linear time invariant) systems. The value
is changed with temperature, charging etc.
3.8V
0.1- 0.3Ω
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Power consumption v.s. time
Power Consumption Analysis with CMW/RTO
Tx/Rx Rx
Idle modeConnected mode
Rx at paging cycle 2.56s
The behaviour of battery voltage is related to the internal
resistance.
435
mW390
mW56 mW
168
mW
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Power consumption v.s. UL transmission power
Power Consumption Analysis with CMW/RTO
Tx power -2dBm 3dBm 8dBm 13dBm 18dBm
Consumption 435.68mW 441.39mW 447.68mW 468.68mW 498mW
(Base Station) Cell power and power control setting has impact on the DUT UL(Tx)
power at area tracking update.
The UL transmission has impact on system power consumption.
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Power consumption v.s. Connected DRX
Power Consumption Analysis with CMW/RTO 20
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Power consumption v.s. Connected DRX
UE listen to PDCCH
Power Consumption Analysis with CMW/RTO 21
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Power consumption v.s. Paging cycle
Power Consumption Analysis with CMW/RTO
The UE active the Rx and listen the PDCCH channel at paging cycle.
Paging 640ms Paging 2560ms
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Power Consumption v.s. eDRX (Idle)
Power Consumption Analysis with CMW/RTO
eDRX disable eDRX enable
Paging 2.56s Paging 5.12s
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Power consumption v.s. Power Save Mode
Power Consumption Analysis with CMW/RTO
DUT waking up
consume power
T3324 is initiated by
UE (AT command)
The sleep period has extreme low power consumption (52uW)
The DUT goes this mode, only when T3412 > 120s.
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Take away
Battery internal resistance UL TX
DRX (connected)
eDRX (Idle)
Power Save Mode
For 10 years?Other features
Coverage enhancement (CE)
U-Plane/C-Plane IP/non-IP
...
Power Consumption Analysis with CMW/RTO 25
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Power consumption measurement solution from Rohde & Schwarz
Power Consumption Analysis with CMW/RTO 26
Channel 2
PMIC GPIO
µP
LTE
1.8 V
3.3 V
2.8 V
MinMaxAvgRMS
X
Current
Voltage
Power V
I Dec
imin
atio
nA/D
A/D
Channel 1
Device under test (DUT)R&S®CMW500 network emulator
R&S®RT-ZVC power probe
to Ch.#2
R&S®CMWrune.g. LTE-Cat1
IoT
app.
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R&S®CMWrun: power consumption monitor with signaling events
Power Consumption Analysis with CMW/RTO 27
Test sequencertool
Power consumption monitor
Voltage
Power
Current
UL Power: 0 dBm
UL Power: 10 dBm
UL Power: 23 dBm
Event Marker
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CMWrun power consumption and IP monitoring testplan
Power Consumption Analysis with CMW/RTO 28
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Both, deep-dive multi-domain measurements and long-run analysis/
optimization with a universal power probe R&S®RT-ZVCxxA
Power Consumption Analysis with CMW/RTO 29
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Your Partner in testing the Internet of Things
Power Consumption Analysis with CMW/RTO 30
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