CSEM Scientific and Technical Report 2008

Wireless Sensor Networks Built Using the Ultralow-power WiseNET SoC
E. Le Roux, P. Volet, V. Peiris, A. Vouilloz, P. Dallemagne, M. Séneclauze, A. J. Restrepo Zea, C. Henzelin, D. Manic
CSEM engineered the ultralow-power System-on-Chip and WiseMAC protocol, the two basic building blocks for the realization of autonomous
wireless sensor networks, which is demonstrated in conjunction with in-house developed data visualization and management tools.
Ultralow-power consumption is a key requirement of Wireless
Sensor Networks (WSN) that sustain applications running for
several years without changing or recharging their batteries.
WSN built using the CSEM WiseNET platform demonstrate
such ultra low-power performance.
The WiseNET system includes an ultralow-power
System-on-Chip (SoC) hardware platform (called WiseNET
SoC [ 1] ), and a low power medium access control protocol
(MAC), called WiseMAC [ 2 ] . Both elements have been
designed to meet the specific requirements of WSN and are
particularly well suited to ad-hoc and hybrid networks. The
combination of the WiseNET SoC and WiseMAC protocol
consumes 250 times less power than comparable solutions
based on the IEEE 802.15.4 standard.
The WiseNET SoC radio [1] offers 434 MHz as well as
868 MHz band and runs from a single 1.5 V battery [ 3] . It
consumes only 2.5 mW in receive mode with a sensitivity
smaller than –108 dBm at a BER of 10 −3 and for a 100 kb/s
data rate. In addition to this low-power radio, the WiseNET
SoC also includes all the functions required for data
acquisition, processing and storage of the information
provided by the sensors.
The WiseNET system is illustrated in Figure 1. Embedding the
WiseMAC protocol on the WiseNET SoC, a demonstrator has
been developed including the following items:
• WiseNET modules (presented in Figure 1) with SR44
silver oxide button cell batteries. The size of such a
WSN node is 46x25x12 mm.
• Larger modules with low-cost alkaline AA battery
allowing very long lifetime without human intervention
(i.e. changing the batteries).
• Gateway USB module for interconnecting the WSN
with a PC.
• A database to store and manage the data sent and
received from the WSN.
• A graphical PC application for the visualization of data
and control of the network, connected to the database.
The modules have integrated temperature and pressure
sensors, but can be adapted for other sensors. The
visualization software is used to observe the network topology
and control it (see Figure 2).
The resulting networks achieve unprecedented low-power
performances with long range and ad-hoc meshed behaviour
with the following characteristics:
• Several years of autonomy with an AA alkaline cell
• 25 kbit/s peak data rate
• 1 km range outside & over 10 m in-building range
• Self-routing and re-organizing meshed architecture.
The WiseNET SoC, co-developed and industrialized through
Semtech, is currently in production and available from
Semtech (SX1282 part number [3] ).
Figure 1: WSN built using the ultra low-power WiseNET SoC. A large
number of nodes could be for example implemented on large
constructions for structural monitoring.
Figure 2: Visualization of a WiseNET network, along with sampled
data display
[1] V. Peiris, et al., “A 1V 433/868MHz 25kb/s-FSK 2kb/s-OOK
RF Transceiver SoC in Standard Digital 0.18µm CMOS”, in Int.
Solid-State Circ. Conf. Dig. of Tech. Papers, Feb. 2005, 258-259
[2] A. El-Hoiydi, et al., “Implementation of an Ultra Low-Power
Self-Organizing Multi-Hop Wireless Sensor Network”, CSEM
Scientific Report 2004, page 74
[3] http://www.semtech.com/pc/downloadDocument.do?id=2792
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