AN ARCHITECTURE FOR ENVIRONMENTAL MONITORING

AND CONTROL IN MUNICIPAL SCALE

Felipe Marques Pires, Rodrigo Sanches Miani and Leonardo de Souza Mendes

Department of Communication, School of Electrical and Computer Engineering, State University of Campinas

Av. Albert Einstein, 400, Cidade Universitária ”Zeferino Vaz”, Distrito Barão Geraldo, Campinas, SP, Brazil

Keywords:

Wireless sensor networks, IEEE 802.15.4, Metropolitan broadband access networks, Municipal monitoring

and control, ZigBee.

Abstract:

Advances in smart sensors, communication technologies and embedded computing allow to have an inter-

action between digital and physical worlds. This paper presents an architecture of combining ZigBee with

Metropolitan broadband access networks in order to build an architecture for monitoring and control in a mu-

nicipal scale. A prototype alarm system was implemented based on this architecture as a proof of concept.

However there is a wider range of applications that can be designed using this architecture to provide reliable

services for government and communities.

1 INTRODUCTION

City environments monitoring and control represent a

class of municipal services with huge beneﬁts for city

management, government administration and society

as a whole. The focus of this work is to present an

architecture to integrate physical characteristics from

the real world with computing systems through sen-

sor and actuator networks, and devices connected in

a metropolitan broadband access network (MBAN) to

reach municipal scale.

Our proposed architecture uses the ZigBee stan-

dard for implementing sensor and actuator networks

in a small scale that are connected through a gate-

way to the metropolitan broadband access network

enabling to gather information and send commands

to devices inside the environments from anywhere in

the city.

ZigBee is a wireless technology for inexpensive,

short range networks, ideal for control of a large num-

ber of devices and machine to machine communica-

tion over a network. Traditional sensors are not able

to obtain particulars inputs and reporting the data in

real time and with high spatial density as sensor net-

works are able to do (Horton and Suh, 2005). Due

to these characteristics mentioned, ZigBee is largely

used into ﬁeld of automatic control, energy monitor,

light control, home security, remote control and smart

environments creation.

In this paper we present an architecture for mon-

itoring and control in the city environments. We also

describe some possible services that could be applied

in city environments. An alarm system implementa-

tion based on our architecture is also presented, which

is being developed in the city of Pedreira, Brazil.

The next section presents related works and success-

ful case studies. Section 3 introduces a background

of metropolitan broadband access networks and the

structure of the ZigBee standard. Section 4 describes

in more detail the proposed architecture. Section 5

presents the implementation of an alarm system as a

proof of concept. Finally, the last section presents the

conclusions and the future works.

2 RELATED WORKS

Other works such as (Gniadek et al., 2008), (Mor-

reale, 2008) and (Mainwaring et al., 2002) also imple-

ment sensor networks for environmental monitoring.

Gniadeck (2008) presented their experience in build-

ing an infrastructure of combining ZigBee with Web

Services for remote accessing and control of a net-

work. A framework was developed based on above

infrastructure to implement a trafﬁc monitoring sys-

tem.

Other implementation for trafﬁc monitoring can

be found in (Morreale, 2008), Street Corners network

was deployed on the Kean University campus, which

Marques Pires F., Sanches Miani R. and de Sousa Mendes L. (2009).

AN ARCHITECTURE FOR ENVIRONMENTAL MONITORING AND CONTROL IN MUNICIPAL SCALE.

In Proceedings of the International Conference on Wireless Information Networks and Systems, pages 27-31

DOI: 10.5220/0002227700270031

 SciTePress

is a network architecture to integrate active and pas-

sive sensors information gathered from urban envi-

ronmental sensing networks. Their implementation

uses sensors from Crossbow Technology, Inc., that in-

cludes IEEE 802.15.4/ZigBee compliant processors.

Mainwaring (2002) presented a system architec-

ture for real-world habitat monitoring, specially to

monitor seabird nesting environment and behavior in

a small island off the coast of Maine called Great

Duck Island.

Discussions about design and metropolitan broad-

band access network implementation can be found in

(Alexiou et al., 2005) and (Balhoff and Rowe, 2005).

Case studies and successful deployment results of

MBANs are presented in (Ford and Koutsky, 2005)

and (Kramer et al., 2006).

We also propose an architecture for environmental

monitoring which has some relations with mentioned

works. However, our proposal presents considerable

differences and beneﬁts such: Two way communica-

tion system, where monitoring and also control over

the environment can exist. Municipal scale monitor-

ing and control, the area covered by this infrastruc-

ture is highly large. Diversity of services that can be

offered to cities, the proposed architecture can be de-

ployed in a wide range of environments, bringing to

cities technology and comfort to its society.

3 TECHNICAL OVERVIEW

3.1 Metropolitan Broadband Access

Network

A Metropolitan broadband access network can be de-

ﬁned as the integration of services, applications and

the infrastructure of a communications network of

a city. It works with high bandwidth transmission

capacity and can support information from a wide

range of services, all based on the Internet protocol

(Mendes, 2006).

A MBAN can be classiﬁed according to the three

layers model presented in Figure 1 (Miani et al.,

2008).

A Metropolitan broadband access network can be

based on four technologies: optic, wireless, dedicated

access (e.g. ADSL, cable network and frame relay) or

hybrid. The limitation of resources and the demand

for transmission capacity are some factors that can

be used to choose one of these technologies. A

MBAN can also be classiﬁed according to the type of

the points connected. There are three categories of

connections: i) public buildings (schools, hospitals,

Network

Structure

ADSL, Optical fiber, Wireless

and Hybrid

Interconnection

Points

Public buildings, private

buildings and residences.

Services

VoIP, E-government,

Internet distribution

Layer

Name

Examples

Figure 1: MBAN classiﬁcation model.

etc); ii) private buildings (companies, industries); and

iii) residences.

Once the infrastructure is ready, several services

can be made available for the metropolitan network

users, as shown in (Ford and Koutsky, 2005) and

(Bauer et al., 2002). Some of these are: Internetdistri-

bution, VoIP, e-government systems, information pro-

grams for education departments, and video sharing

systems.

3.2 ZigBee and IEEE 802.15.4

ZigBee is a wireless communications standard man-

aged by ZigBee Alliance, a group over 170 companies

creating ZigBee related semiconductors, developing

tools and products. Solutions adopting the ZigBee

standard are embedded in consumerelectronics, home

and building automations, industrial control, sensor

networks and so on. The ZigBee stack architecture is

separated in a set of blocks called layers. Each layer

performs a speciﬁc set of services for the layer above

(ZigBee-Alliance, 2008).

The IEEE 802.15.4 standard deﬁnes the respon-

sibilities of the physical (PHY) layer and medium

access control (MAC) sub-layer. IEEE 802.15.4

has two physical layers that operate in two different

frequency ranges, 868/915 MHz and 2.4 GHz. The

MAC sub-layer controls access to the radio channel

using a Carrier Sense Multiple Access/Collision

Avoidance (CSMA-CA) mechanism. MAC layer

responsibilities may also include transmitting beacon

frames, synchronization, and providing a reliable

transmission mechanism. The ZigBee speciﬁcation

WINSYS 2009 - International Conference on Wireless Information Networks and Systems

deﬁnes the network (NWK) and application (APL)

layers (Gutiérrez, 2007). Figure 2 brieﬂy describes

relevant layers and related information.

Figure 2: ZigBee stack architecture.

ZigBee was designed for low power applications

and it ﬁts well into embedded system and those mar-

kets where reliability and versatility are important but

high bandwidth is not. Low power consumption en-

ables to deploy ZigBee devices and sensors in wider

areas where power supply is not presented offering

extended battery life. ZigBee also offers support of

large network size comparing to other technologies,

it has the capacity of supporting over 64000 devices

within a network, which makes it possible to deploy

sensor at a very high density, which is essential to cer-

tain applications such as monitoring and control in a

large scale.

4 SYSTEM ARCHITECTURE

Interfacing to the physical world involves exchanging

energy between embedded devices and their environ-

ments. Usually, each device is either a sensor node or

an actuator node. Sensor nodes translate a particular

form of energy or a phenomena (light, heat, vibration)

into information. Actuator nodes convert information

into action over the environment around them (Estrin

et al., 2002).

As stated earlier, the proposed architecture com-

bines ZigBee wireless technology with Metropolitan

broadband access network in order to create a large

sensor/actuator network to monitor and control city

environments such as hospitals, schools, health cen-

ters, government buildings, streets and other public

spaces. This architecture allows an interaction be-

tween physical characteristics from real cities with

computational tools, resulting in a system where in-

formation from real environments can be accessed

and manipulated by speciﬁc communities, govern-

ment employees, and also to be used to create smart

environments.

The architecture lowest level consists of the

sensor/actuator nodes that interact directly to the

environment based on their physical characteristics.

Nodes may be deployed around the environment

in a large number. The sensor nodes transmit their

data through the ZigBee network to the network

gateway. The gateway is responsible for trans-

mitting sensor data from the sensor patch through

the Metropolitan broadband access network to the

remote base station where a software application

processes the data and ﬁnally such information is

displayed to the users through an user interface.

The same happens with the actuator nodes, however

in an opposite way, data is transmitted by user

commands from remote base stations to the actuator

nodes which respond the request with actions over the

environment. The architecture is depicted in Figure 3.

Figure 3: Architecture model.

The number of remote base stations probably will

increase in parallel with new services. This reason is

because different environments should be monitored

and controlled by different people or companies. For

example, informations about all health centers should

be concentrated in a base station where people are ca-

pable to monitor and control these environments. In-

formation about trafﬁc monitoring should be transmit-

ted to its speciﬁc base station and so on.

AN ARCHITECTURE FOR ENVIRONMENTAL MONITORING AND CONTROL IN MUNICIPAL SCALE

4.1 Services

A wide range of services can be developed using the

proposed architecture, and the most of them can be

used for government administration proposal. De-

pending on the cities needs new environmental mon-

itoring and control solutions can be developed, im-

provements in existing infrastructures can be made to

achieve a high spatial resolution, artiﬁcial intelligence

can be applied in some cases creating smart environ-

ments with a certain level of autonomy.

5 CASE STUDY: ALARM SYSTEM

In our deployment, we are using XBee OEM RF

Modules from Digi International, Inc. to develop an

alarm system in Pedreira, a city localized in south

east of Brazil. Pedreira has a Metropolitan broadband

access network since 2007, it was a project developed

in agreement between the State University of Camp-

inas (UNICAMP) and the government of Pedreira.

The network infrastructure is constituted by a optical

backbone and wireless digital radio communication

as presented in Figure 4, which connects the city

health centers, hospitals, schools and other important

buildings.

Figure 4: MBAN of Pedreira.

The XBee OEM RF Module was engineered to

meet IEEE 802.15.4 standards and support low-cost,

low-power wireless communication. The module op-

erates within the ISM 2.4 GHz frequency band. It

can operate in different topologies either point-to-

multipoint or ZigBee/Mesh topologies, depending on

the ﬁrmware conﬁguration inside the module and for

what application is destined (Digi, 2008).

The gateway was developed using the same mod-

ule described above using an USB interface board,

which takes all data collected from nodes around the

environment and by a computer software transmits

all information through a TCP connection over

the MBAN to a remote base station. For software

implementation was used JAVA language. The OEM

RF Module and the USB interface board is presented

in Figure 5.

Figure 5: USB interface board.

The nodes embedded around the environment use

the same OEM RF Module to communicate with

the gateway. The module is mounted in a manager

board presented in Figure 6, which is used to imple-

ment sensor and actuator nodes, this solution also

enables to collect information from other instruments

through serial interfaces RS232, TTL 5V and TTL

3.3V, where data gathered is transmitted via ZigBee

network to the gateway.

Figure 6: Sensor and actuator board.

The alarm system is being implemented as a proof

of concept which consists of two motion sensors that

monitor intrusion in a public building from the city

of Pedreira. The sensors are spread through the en-

vironment, when a minimal motion is sensed by one

of the sensors a signal is sent to the gateway. The

gateway collects the signal and forwards a message

over the MBAN to a base station localized in other

building inside the city. The user interface receives

the message, processes it and alerts the user that one

of the sensors was activated. Also the user has the

possibility to control a device inside the environment

in anytime.

WINSYS 2009 - International Conference on Wireless Information Networks and Systems

6 CONCLUSIONS

City environments monitoring and control represents

an important class of municipal services and an inter-

esting application of sensor/actuator networks in mu-

nicipal environments. Our proposal differs from other

works specially for offering control over the environ-

ment instead of just monitoring. Another beneﬁt is the

large scale infrastructure provided to cover city areas

and the diversity of services that can be integrated in

municipal scenario.

Our alarm system is the ﬁrst implementation for

monitoring and control in such infrastructure. How-

ever, future works are expected which includes the de-

sign and implementation of new applications, devel-

opment of new hardwares for speciﬁc tasks, creation

of a platform to group data from related environments

in order to organize the base station and the types of

monitoring and control. Pervasive computing also are

being studied to be applied in some future implemen-

tation to achieve a certain level of intelligence in pub-

lic spaces.

REFERENCES

Alexiou, A., Bouras, C., Igglesis, V., Kapoulas, V.,

Paraskeuas, M., Scopoulis, I., and Papagiannopoulos,

J. (2005). Deployment of broadband infrastructure in

the region of western greece. In Broadband Networks,

2005 2nd International Conference on, pages 1510–

1515Vol.2.

Balhoff, M. J. and Rowe, R. C. (2005). Municipal broad-

band: Digging beneath the surface. Technical report,

Balhoff & Rowe, LLC.

Bauer, J., P., G., Kim, J., Muth, A. T., and Wildman, S. S.

(2002). Broadband: Beneﬁts and policy challenges.

Technical report, Michigan State University.

Digi (2008). (online) Digi International Inc. IEEE 802.15.4

OEM RF Modules by Digi International, [Accessed

10th October 2008] Available from World Wide

Web: http://www.digi.com/products/wireless/point-

multipoint/xbee-series1-module.jsp/.

Estrin, D., Culler, D., Pister, K., and Sukhatme, G. (2002).

Connecting the physical world with pervasive net-

works. Pervasive Computing, IEEE, 1(1):59–69.

Ford, G. S. and Koutsky, T. M. (2005). Broadband and

economic development: a municipal case study from

ﬂorida. Review of Urban & Regional Development

Studies, 17(3):216–229.

Gniadek, A., Li, Y., Lung, C.-H., and Wei, Q. (2008). A

web services-based infrastructure for trafﬁc monitor-

ing using zigbee. Sensor Technologies and Appli-

cations, 2008. SENSORCOMM ’08. Second Interna-

tional Conference on, pages 562–567.

Gutiérrez, J. A. (2007). On the use of ieee std. 802.15.4 to

enable wireless sensor networks in building automa-

tion. International Journal of Wireless Information

Networks, Volume 14:295–301.

Horton, M. and Suh, J. (2005). A vision for wireless sensor

networks. Microwave Symposium Digest, 2005 IEEE

MTT-S International, pages 361–364.

Kramer, R. D. J., Lopez, A., and Koonen, A. M. J. (2006).

Municipal broadband access networks in the nether-

lands - three successful cases, and how new europe

may beneﬁt. In AcessNets ’06: Proceedings of the 1st

international conference on Access networks, page 12,

New York, NY, USA. ACM Press.

Mainwaring, A., Culler, D., Polastre, J., Szewczyk, R., and

Anderson, J. (2002). Wireless sensor networks for

habitat monitoring. In WSNA ’02: Proceedings of the

1st ACM international workshop on Wireless sensor

networks and applications, pages 88–97, New York,

NY, USA. ACM.

Mendes, L. (2006). Infovia municipal: Um novo paradigma

em comunicações. In State University of Campinas.

School of Electrical and Computer Engineering.

Miani, R. S., Zarpelão, B. B., de Souza Mendes, L., and Jr.,

M. L. P. (2008). Metrics application in metropolitan

broadband access network security analysis. In SE-

CRYPT 2008 - International Conference on Security

and Cryptography, pages 473–476.

Morreale, P. (2008). Street corners: Architecture for cor-

relation of networked environmental sensors. Systems

Conference, 2008 2nd Annual IEEE, pages 1–6.

ZigBee-Alliance (2008). (online) ZigBee

Speciﬁcation. [Accessed 15th November

2008] Available from World Wide Web:

http://www.zigbee.org/Products/Technical/Documents

Download/tabid/237/Default.aspx/. Document

053474r17.

AN ARCHITECTURE FOR ENVIRONMENTAL MONITORING AND CONTROL IN MUNICIPAL SCALE