Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
1
Microelectronic Solutions for
Water Metering and Monitoring
Prof. Dr.-Ing. Axel Sikora, Dipl.-Ing. Dipl. Wirt.-Ing.
Dipl.-Inform. (FH) Manuel Schappacher
Lab Embedded Systems and Kommunikationselektronik
HS Offenburg
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
2
Table of Contents
1. introduction & requirements
2. MAC layer approaches
3. network layer approaches
4. application layer approaches
5. water monitoring example
6. status & outlook
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
3
ch.1.1: introduction – motiviation
• Cyber Physical
Systems (CPS)
• Internet of Things
(IoT)
• Ambient Intelligence
• in practically all
applications
– interesting: vertical
and horizontal (!)
integration
– TeleX Applications
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
4
ch.1.1: introduction – motiviation
• need of embedded low cost and
low energy communication
• does wireless mean
– „less wires“?
– or „no wires“?
• energy provision is of key
importance for many use cases
• requirement: freedom of maintenance
at least 5 – 10 years
– battery lifetime
– energy harvesting systems
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
5
ch.1.2: introduction – layer split
• protocol development for energy autarkic systems affects all layers
• L1 (physical layer):
– energy efficient transceivers
– energy efficient modulation schemes
– wakeup technologies
– silicon technologies
• including circuit design (e.g., PLL, wakeup circuits, …)
• L2 (data link layer):
– frame formats
• synchronisation
• sleep modes
– topologies
– network registration & administration
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
6
ch.1.2: introduction – layer split
– L3 (network layer):
• energy aware / energy efficient routing
– L4 (transport layer) :
• energy efficient retransmissions / reliability
– L7 (application layer):
• data formats
– CoAP or alike
• network administration
• operation schemes
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
7
ch.2.1: MAC – energy consumption
• energy consumption is of key importance
• power consumption
– practically modern RF transceiver allow „low“ power consumption
– for SRWN mostly identical in TX and RX (!!!) mode
• minimum around 10 mA @ 1,5 … 1.8V
• typical 15 … 20mA @ 1,5 … 1.8V
– TI CC1125: 46 mA @ 3 V @ output power of 16 dBm.
» nearly 29 % efficiency from electrical input power to radiated power at antenna
– Si446x transceivers draw 30 nA in shutdown mode and 50 nA in standby
– TI CC1120 transceivers draw 0.5 µA in timer mode
• reduction of energy consumption with extensive sleeping
– student approach
actstdbyactopmean rIrII 1
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
8
ch.2.2: MAC – energy consumption – sensor / sender sleeping
• sleeping modes are very practical for many sensor applications – wakeup device by own interrupt
• i/o interrupt
• timer interrupt
– application examples:
• regular sensing, e.g. temperature sensor
– event driven sensing, e.g. light switch
– requires receiver, which is „always on“
• necessity to be mains powered
• receiver can be end or forwarding node
– coordinator, router, „mailbox“
– examples
• EnOcean Radio Protocol
• ZigBee PRO Green Power
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
9
ch.2.3: MAC – energy consumption – actuator / receiver sleeping –
synchronisation
• problematic use cases: – polled sensors
– actuators
• fire detector & alarm
• access systems
• medical implants
• routing nodes
• in case of sleeping period T – worst case latency T
– average latency T/2
• both sides of the network can sleep – synchronisation
• examples: – Wireless M-Bus EN13757-4 Q-mode (precision timing)
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
10
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sniffing /eWOR – RX sniff mode
RX sniff mode
For battery operated systems the RX current is an important parameter and to increase battery lifetime. RX Sniff Mode
can be used to sniff for RF activity using an ultra-low-power algorithm. By increasing the preamble of the transmitted packet, the
receiver can implement RX Sniff Mode and wake up at an interval that ensures that at least 4 bits of preamble is received. RX
termination based on CS greatly reduces the time in RX and forces the radio back in SLEEP if there is no signal on the air.
Que
lle: C
C112X
/C
C1175 L
ow-P
ower
Hig
h P
erfo
rman
ce
Sub
-1 G
Hz
RF
Tra
nsce
iver
/T
rans
mitte
r –
Use
r‘s
Gui
de
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
11
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sniffing /eWOR – RX termination
RX termination to save current
When implementing the RX Sniff Mode, the radio should
terminate RX as fast as possible if there is no signal on the
air to minimize the current consumption. The radio can
terminate the RX mode in lack of a carrier or in lack of
preamble.
basic RX termination methods
Which RX termination to use (CS or PQT) depends on the
system requirements and the environment the system is
operating in.
Carrier Detection Detecting a carrier takes less time compared to detecting a
preamble and therefore the wake-up timeout may be
shorter. However this can only be applied to a “non-
noisy” network
PQT Detection Detecting a PQT takes longer time compared to detecting
a carrier and the wake-up timeout must be shorter when
RX termination is based on PQT compared to CS.
Que
lle: C
C112x
/C
C120x
RX
Sni
ff M
ode
– s
wra
428a
– O
ctob
er 2
013
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
12
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sniffing /eWOR – RX termination
MCU based RX termination
The MCU terminates RX after a timeout equal to the length
of the preamble and sync word. As seen from the figure, this
leads to an even lower current consumption on the radio, but
the MCU will draw some more current compared to case A
and case B.
Que
lle: C
C112x
/C
C120x
RX
Sni
ff M
ode
– s
wra
428a
– O
ctob
er 2
013
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
13
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sniffing /eWOR – Smart Preamble
decrease power consumption
RX Sniff Mode functionality may dramatically decrease
the average power consumption of a receiver by using
long preamble sequences. Long preamble allows the
receiver to sleep for longer periods of time and still
reliably receive the data payload. When the radio wakes
up and goes into RX it uses CS or PQT termination to
detect if there is a signal. If a signal is found, the radio
waits in RX until the sync word is detected.
Smart-Preamble
While using long preamble sequences allows the radio to
sleep longer, it also means that if it wakes up early in the
preamble it has to stay a long time in RX before sync is
found. Smart-Preamble allows the radio to sleep while
waiting for sync, which greatly reduces the current
consumption
Que
lle: C
C112x
/C
C120x
RX
Sni
ff M
ode
– s
wra
428a
– O
ctob
er 2
013
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
14
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sniffing
• key elements
– fast power up / settling time
• including frequency offset compensation (AFC)
• including automatic gain control (AGC)
• latest transceivers reach tidle → rx = 100 … 200 µs
– partial power up
• e.g. for energy detection only
• e.g. for address detection
– selective wakeup might decrease activity rate and reduce attack possibilities
• example 1:
– Wireless M-Bus EN13757-4 S-mode (stationary mode)
• preamble length 576 bits
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
15
ch.2.4: MAC – energy consumption – actuator / receiver sleeping –
sample calculation
• sample calculation use sniffing modes
• AMI53000 has activation time < 100µs
– sniffing time can be reduced to ~ 130µs
Iquiescent [A] Itransmission [A] Isniff [A]
AMI53000 2,00E-06 1,74E-02 1,20E-02
MSP430 @1MHz, 3V, 85°C 2,80E-06 3,00E-04 2,80E-06
additional components 5,00E-03 5,00E-03
sum 4,80E-06 2,27E-02 1,70E-02
sniff cycle [s] average current [A]
2 5,90E-06
5 5,24E-06
10 5,02E-06
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
16
ch.2.5: Mobile Communication
• P2P smart metering
(gas & water)
– 5-8a
• measurement and
optimization of
GPRS & UMTS
communication
– indoor / outdoor
– roaming
– daytime
• achieved
optimization of
around 50%
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
17
ch.3.1: NWL – MAC approaches
• all nodes (intermediate &
end) nodes except the
sender are receivers
• the MAC problem is
scaled to routed networks
– overall synchronisation
– hop by hop
synchronisation
• example Wireless HART
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
18
ch.3.1: NWL – MAC approaches – example 2
• 6LoWPAN
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
19
ch.3.1: NWL – MAC approaches – example 2
• hop by hop sniffing
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
20
ch.3.1: NWL – MAC approaches – example 2
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
21
ch.3.2: NWL – energy aware routing – example 3
• practically all legacy routing protocols perform optimization
of a cost function
• typical parameters for SRWNs
– SNR
– # of hops
– ressources
• energy aware routing includes energy state of the nodes
• In most cases, the following five parameters are regarded:
1. node residual energy,
2. energy for transmission process,
3. energy for reception process,
4. replenishment rate, and
5. activity rate Source: L. Longbi, N.B. Shroff, R. Srikant, Asymptotically optimal energy-aware routing for multihop
wireless networks with renewable energy sources, IEEE/ACM Trans. Netw. 15(5): 1021-1034 (2007).
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
22
ch.3.3: NWL – energy aware routing – project example
• Remote wireless water meter
reading solution based on the
EN 13757 standard, providing
high autonomy, interoperability
and range.
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
23
ch.3.3: NWL – energy aware routing – project example
• objectives
– energy autonomy
– P-mode & Q-mode
(incl. routing)
– energy-aware routing
– tool support
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
24
ch.3.3: NWL – energy aware routing – project example
Fig. 4: data field format for search request; (a) as standardized in [7], (b) as proposed extension
Fig. 5: data field format for search response; (a) as standardized in [7], (b) as proposed extension
Fig. 6: data field format for energy level
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
25
ch.3.4: NWL – energy aware routing – simulation example
• simulation: optimization of topologies
and output power
– including collision probability
0,0125
0,0375
0,0625
0,0875
0,1125
0,1375
0,1625
0,1875
0,2125
0,2375
0,2625
0,2875
0,3125
0,3375
0,3625
0,3875
0,4125
0,4375
0,4625
0,4875
R1
R5
R9
0,00E+00
5,00E-06
1,00E-05
1,50E-05
2,00E-05
2,50E-05
3,00E-05
3,50E-05
r/dPtx,r
0,01
0,1
0,0125
0,0375
0,0625
0,0875
0,1125
0,1375
0,1625
0,1875
0,2125
0,2375
0,2625
0,2875
0,3125
0,3375
0,3625
0,3875
0,4125
0,4375
0,4625
0,4875
R1
R5
R9
0,00E+00
5,00E-06
1,00E-05
1,50E-05
2,00E-05
2,50E-05
3,00E-05
3,50E-05
r/dPtx,r
0,01
0,1
dd
d
r r
d
r/2
r/2
d
r r
d
r/2
r/2
Source: A. Sikora, M. Ostesteanu, "Power Consumption Models for Wireless Grid Networks",
WSEAS Conf., Special Session: Intelligent Systems & Adaptive Control, Venice, 2.-4.11.2005.
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
26
ch.3.5: NWL – routing with unidirectional nodes
• practically all legacy routing protocols start routing process from
the sender node
• extension to EnOcean Radio Protocol (ERP)
– unidirectional senders
– necessity to start routing
process from the receiver
Source: F. Schmidt, W. Heller, D. Rahusen, A. Sikora, V. Groza, "Design and Implementation of a Routing Protocol for Seamless Integration of
Unidirectional Energy-Autarkic Wireless Sensor Nodes", IEEE I²MTC Int'l Instrumentation and Measurement Conference, 2010.
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
27
ch.4: APL
• objectives for energy autarkic systems
– reduce duty cycle for data transmission
→ use simple frame formats
– reduce duty cycle for network management
→ use simple management protocols / small number of simple commands
• general challenge for energy harvesting systems
– need energy for commissioning
– how to fill the reservoir at commissioning?
→ use hybrid systems
energy harvesting for prolongation of life time
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
28
ch.5.1: Wireless Sensor Development for Waterway Monitoring –
Use Case
• flooding 13.05.1999
28
• volume flow ca 3600m3 (at Breisach)
source: http://www.hhh-ev.de
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
29
ch.5.1: Wireless Sensor Development for Waterway Monitoring –
Use Case
• building reservoirs
29
mar 2011
jul 2009
jan 2009
source: http://www.hhh-ev.de
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
30
ch.5.2: Wireless Sensor Development for Waterway Monitoring –
Use Case
30
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
31
ch.5.2: Wireless Sensor Development for Waterway Monitoring –
Use Case
• topology &
transversal
profile
31
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
32
ch.5.3: System Design – Hardware
• relais station
32
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
33
ch.5.3: System Design – Hardware
• measuring point
33
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
34
ch.5.3: System Design – Hardware
34
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
35
ch.5.4: System Design – Firmware
35
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
36
ch.5.5: System Monitoring Software
36
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
37
ch.5.5: System Monitoring Software
37
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
38
ch.5.6: lab test setup
• emutator test bed
38
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
39
ch.5.6: lab test setup
39
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
40
ch.5.7: field test setup
40
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
41
ch.5.7: field test setup
41
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
42
ch.5.8: field test results
42
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
43
ch.5.8: field test results
43
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
44
ch.5.8: field test results
• Measuring point 1
– 200m LOS
44
• Measuring point 2
– 2750m NLOS
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
45
ch.6: status & outlook
• increasing experience with energy harvesters
• increasing experience with wireless network protocols
• increasing performance of semiconductor devices
• increasing opportunities for real product development
• but why are there so few products out yet ???
• major challenges:
– currently very few options for standardized solution
• mostly very application specific
– cost
• continue R&D efforts
• continue standardisation efforts
Prof. Dr.-Ing. Axel Sikora
Dipl.-Ing. Dipl. Wirt.-Ing.
Symposium on Telemetry Systems
for Water Management
46
Thank you for listening !
Thanks for your participation !
Thanks for the amicable cooperation!
Questions?
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