Application-Oriented Wireless Sensor Network Communication Protocols and Hardware Platforms: a Survey Zhongmin Pei*, Zhidong Deng, Member, IEEE, Bo Yang, Xiaoliang Cheng Department of Computer Science, Tsinghua University, Beijing 100084, China Tel: +86-10-62777704, Fax: +86-10-62796830 * E-mail:
[email protected] Abstract-With the promotion of industry community, wireless
physical interfaces, and defines the wireless communication
sensor network (WSN) has been widely applied to many fields. In
specification and interoperation for smart sensor network [4].
this paper, current research status and possible development
On October 2006, IEEE 802.15.4a wireless communication
trend of application-oriented wireless sensor network (AOWSN)
standard with 2Mbps data transmission rate is approved [5]. It
are introduced firstly. Second, we analyze and compare the short
makes multimedia WSN applications possible. Short distance
distance wireless communication protocols that can be used in
wireless communication standards, such as Bluetooth, UWB ,
WSN such as ZigBee, Wibree, Rubee, IEEE 802.15.4a, Z-Wave
ZigBee, IEEE 802.15.4a, WiBree, and Rubee bring multiple
etc. The advantage and disadvantage of these protocols are
choices for various WSN applications.
discussed. Third, AOWSN hardware core modules, including
On March 2006, Sun Corp. published a WSN development
radio frequency (RF) and micro controller unit (MCU) chips are
platform based on Java and ARM9 core, called SPOT [6]. Intel
analyzed. We then investigate the hardware components of
released the Imote2 sensor node based on PXA271 XSCAL
current popular WSN nodes such as MICAz, iMote2, SPOT, and
high performance processor. OKI and Jennic also released their
XYZ. Fourth, we describe the Cicada series of nodes that are
own hardware development platform for WSN based on 32 bit
developed in this paper. Finally, we draw conclusion.
processor. The improvement of processing and storage capacity enables WSN node to carry out complex algorithms
I.
INTRODUCTION
and network protocols.
Up to April 2007, ZigBee Alliance has counted more than
On February 2007, the Nature magazine reported an
214 members, and the standard of ZigBee-Pro version is
approach to produce nanometer biological sensors with
officially made [1]. Subsequently, semiconductor IC suppliers
traditional methods by Yale University [7]. The emergence of
such as TI, Freescale, Ember, OKI, and Microchip release their
new type sensors has greatly promoted the application process
own ZigBee solutions based on System on Chip (SoC) or
of WSN.
System in Package (SiP) single chip, respectively. The price of
These milestone events show that WSN has been
single chip falls to about 4 U.S. dollars. It leads to a new
extensively applied in industry out of library in recent years. In
opportunity to develop a variety of WSN applications based on
this paper, we focus on the following three aspects: WSN
ZigBee standard. At the same time, Z-Ware Alliance for
wireless communication protocols, WSN hardware platforms,
wireless automatic control continues developing, and there are
and the Cicada series of nodes developed by us. The remainder
more than 70 members until now [2]. ISA SP100 committee
of the paper is organized as follows: In Section 2, we analyze
has announced the formation of two new standard working
and compare the short distance and low rate wireless
groups, i.e., SP100.11 and SP100.14, in order to define various
communication protocols which can be used in WSN
kinds
industry
applications. In Section 3, AOWSN hardware platforms are
applications [3]. IEEE 1451.5 working group takes WiFi,
studied. We present our related work on the Cicada series of
BlueTooth, ZigBee wireless communication standards as
nodes in Section 4. Finally, we conclude our paper.
of wireless
connection
standards for
978-1-4244-1706-3/08/$25.00 ©2008 IEEE.
II.
AOWSN COMMUNICATION PROTOCOLS
Due to the requirement for a great diversity of applications, various wireless communication standards are prompted. In WWAN, WMAN, and WLAN areas, CDMA2000, WCDMA, WiMAX, and WiFi have aroused more and more interest. But they are not suitable for use in small, low power devices for their high power consumption. Low rate, low cost, restricted energy, and short distance transmission are main features of WSN applications. Thus, WPAN standards are widely adopted in WSN applications. In WPAN area, Bluetooth, UWB, ZigBee, Z-Wave, RFID, and IRDA standards are stepping towards a new application phase. IEEE 802.15.4a, Wibree, RuBee, IEEE 1451.5, and the other new protocols are rapidly emerging. The following gives a brief introduction of AOWSN
ZigBee stack is made up of the framework for application layer and network layer as shown in Fig. 1 [8]. Network layer responds to build a network, route frames and store neighbor information etc. This layer conceptually includes two service entities: data service and the management service. The application layer framework comprises the application support sub-layer,
the
ZigBee
manufacturer-defined
device
application
objects, objects
and to
the finish
point-to-point addressing, endpoint binding, and service discovering. 2.
Z-Wave protocol Z-Wave protocol defines a two way radio system which
operates at 908MHz. It focuses on these small amounts of data applications such as WSN [9], lighting and appliance control, HVAC, access control, intruder and fire detection etc.
wireless communication protocols.
Therefore it uses a data rate of just 9.6Kbps originally and is A. 1.
Wireless communication protocols for AOWSN ZigBee protocol
extended later to 40Kbps. Developers can setup a mesh network based on a source-routing protocol which was
ZigBee is a self-organized WPAN protocol based on IEEE
developed by Zensys Corp. on top of link layer. Zensys also
802.15.4-2003 MAC and physical layer. Up to now, ZigBee
released ZW0201 single chip which integrates a RF transceiver,
Alliance has released ZigBee 1.0
an 8051 MCU, a Flash storage [10].
and
ZigBee-2006
specifications, and ZigBee-Pro version has also been completed [1]. ZigBee protocol supports star, tree, and mesh topologies. There are three types of devices in ZigBee protocol: coordinator, router, and end device [8]. A PAN only has one coordinator which is responsible for starting the network and choosing network parameters. Two end devices can not communicate with each other. ZigBee protocol supports direct addressing with IEEE 64 bit address, indirect addressing, group addressing and broadcast addressing.
Fig. 2 Z-Wave protocol stack
As shown in Fig. 2 [10], the Z-Wave stack consists of PHY/ MAC layer, transport layer, network routing layer, and application layer. PHY/MAC layer controls access to RF media. It uses FSK modulation with Manchester channel encoding. Transfer layer controls the transfer of data between two nodes including retransmission, checksum check, and acknowledgements. Network routing layer are responsible for package routing between nodes, data retransmitting, scanning Fig.1 Outline of ZigBee stack architecture
network topology and so on. One of the key features of
Z-Wave technology is the routing capability of all the nodes in
project-Standard based on Rubee protocol [14]. IEEE P1902.1
the network. Z-Wave automatically routes the signal from one
will offer a real-time, tag-searchable protocol using IPv4
node to the next. The Z-Wave application layer is responsible
addresses that run at speeds of 300 to 9,600 Baud. Individual
for decoding and executing commands in a Z-Wave network.
tags and tag data may be viewed as a stand-alone, web server
3.
from anywhere in the world. Each enabled RuBee tag can be
Wibree protocol On October 3, 2006, Nokia introduced Wibree technology as
discovered and monitored over the World Wide Web using
an open industry initiative extending local connectivity to
popular search engines such as Google or via the Visible
small devices, which is supported by a group of leading
Asset's Tag Name Server. Interpretabilities of different Corp.’s
companies such as Broadcom , CSR, Epson , Nordic and so on
devices are also defined in specifications.
[11]. Wibree protocol is similar to Bluetooth with 0-10 m
5.
The other WSN-related communication protocols ISA SP100.14 and SP100.11 WG are working to provide a
communication range and 1 Mbps data rate.
complete and integrated set of standards for industrial wireless applications [3]. Working groups will define wireless connectivity standards optimized for industrial monitoring, logging and alerting applications. The standard will address the wireless needs in the industrial environment that includes sensors, wireless workers, first responders, and wireless
infrastructure networks. Coexistence with other wireless devices anticipated in the industrial work space, such as
Fig. 3 Wibree protocol stack
As shown in Fig. 3 [12], Nokia’s Wibree solution has two
IEEE802.15x, 802.16x, and RFID will also be addressed.
and
IEEE P802.15.4a was approved as a new amendment to
Bluetooth-Wibree Dual-Mode Chip. The stand-alone chip is
IEEE Standard 802.15.4 by the IEEE-SA Standards Board on
well suited for applications where only small quantities of data
March, 22 2007 [5]. Standard is based on Chirp Spread
are transferred such as for watches and sports sensors. The
Spectrum(CSS) technology which was jointly proposed by
Bluetooth-Wibree dual-mode chip is designed for use in
Nanotron and Orthotron with 2Mbps data rate, up to 900
Bluetooth devices. Therefore Wibree functionality can be
meters’ range in free space [15]. Currently, Nanotron has
integrated with Bluetooth for a minor incremental cost by
announced its real time location chip: nanoLOC TRX.
implementation
alternatives:
Stand-Alone
Chip
utilizing key Bluetooth components and the existing Bluetooth
The IEEE 1451.5 WG is endeavoring to develop the
RF. This type of implementation allows Bluetooth devices to
specification for a wireless smart sensor standard that will
connect to a new range of tiny battery-powered devices.
allow data interoperability among the various wireless sensor
Wibree protocol is currently in progress.
systems or networks. On March 26, 2007, IEEE 1451.5 has
4.
been approved by IEEE as a full-use standard.
RuBee protocol RuBee is a bidirectional, on-demand, peer-to-peer network
Recently, Echelon Corp. announced a media-independent
protocol that uses long wavelength transceiver mode under 450
control-networking technology that has trained its sights on an
kHz [13]. This protocol can work with networks of many
eventual role in the low cost WSN market [16]. This ‘light’
thousands of tags and has an area range of 10 to 50 feet. The
platform is called Pyxos. Pyxos networks are intended to be
battery life of tags is about 10 years. Rubee is getting support
integrated inside a sensor or actuator. It is regarded as a
from companies such as Metro, Motorola, IBM, Sony,
challenge to ZigBee and Z-Wave standard.
Panasonic and NCR for its character of working in harsh environments such as near steel or water and around corners, where RFID or ZigBee protocol is not applicable to. On June 8, 2006, the IEEE-SA Standards Board approved P1902.1
B.
Comparison of short distance wireless communication protocols Sensors exist everywhere in industry. In fact, the broad
applications of WSN associates closely with the development
of short distance wireless communication standard. Due to the
2, we can observe that SoC or SiP ZigBee single chip solutions
application-related features of WSN, wireless communication
of TI, Freescale, Radio Pulse, Ember, OkI, and Jennic Corp.
area appears a phenomenon of a hundred flowers blossoming
take main place in WSN chip market. Among these ZigBee
as mentioned above. Table 1 gives comparison of these
chips,CC2420 has the lowest TX and RX supply current while
protocols from the perspective of operating frequency brand,
JN513x chip of Jennic has a high consumption. CC2431 chip
range, bandwidth, and consumption.
of TI integrates 8051 MCU core and is designed with location
As shown in Table 1, the power consumption of WiFi is
engine. Freescale is one of the sponsors of ZigBee alliance.
larger than the other protocols. Thus, it is suitable to
Its one-stop ZigBee solutions including MC132x SiP chip and
applications with wired devices such as WLAN devices. UWB
Beekit ZigBee protocol stack software are announced lately.
can be used as a communication protocol of multimedia WSN
IEEE 802.15.4a protocol is based on Nanotron’s CSS
applications such as audio and video due to its large bandwidth.
technique. NA5TR1 is Nanotron’s real time location CSS chip.
The transmission range of Bluetooth protocol is very near and
CSR and TI’s Bluetooth chip are very popular among
the protocol is more complex. Its consumption is larger than
Bluetooth chips. Pyxos FT and ZW0201 chips are main
the other protocols except WiFi and the corresponding size of
products of Pyxos and Z-Wave standards. ZW0201 has higher
networks is restricted. Thus, it can not be used in large scale
sensitivity than the other kinds of chips.
WSN
applications.
Rubee
protocol
has
very
strong
anti-jamming ability and can work in harsh environments. Tiny
TABLE 2 WIRELESS SENSOR NETWORK CHIPS Corp.
RF
Sensitivity
Current
Module
(dbm)
(R,T,mA)
CC2420
-95
19,17.4
Transceiver
CC243x
-94
27 ,25
SoC, 8051 CPU
MC1319x
-92
37,30
Transceiver
MC132x
-92
38,31
SiP, HCS08
MG2400
-99
26,33
SoC,8051 CPU
Ember
EM250
-97.5
35.5,35.5
SoC,16bit CPU
Jennic
JN513x
-97
39, 39
SoC, 32bit CPU
OKI
ML7222
-90
26,24
SoC,8bit CPU
Nanotron
NA5TR1
-95
27,23
802.15.4a
Echelon
Pyxos FT
---
---
Pyxos
Zensys
ZW0201
-101
21,23
Z-Wave
CSR
BlueCore
-85
46,52
Bluetooth
devices or tags are their main target of application. ZigBee and Z-Wave standard are supported by a group of leading companies because of their excellent features. Currently, they
TI
are extensively adopted in WSN applications. TABLE 1 SHORT DISTANCE WIRELESS COMMUNICATION PROTOCOLS Protocol
Operating Band
Range
Bandwidth
Battery
(Hz)
(m)
(kb/s)
Life (day)
75
20-250
1000
2.4G /915M ZigBee /868M
Description
Freescale Radio Pulse
Z-Wave
908M/860M
100
9.6
3650
Wibree
2.4G
10
1000
70
Rubee