22-07-2014, 03:56 PM
Mote Design Supported with Remote Hardware Modifications Capability for Wireless Sensor Network applications
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ABSTRACT
Many Wireless Sensor Networks (WSNs) applications are new and their requirements may not be fully
anticipated during the sensor networks design and development stage. We are presenting a sensor network
infrastructure that support motes’ with remote hardware and software modification to match the target
applications need. Using the proposed infrastructure in next-generation WSNs will produce flexible
infrastructures that will provide over-the-air remote design modification even after the deployment of
WSNs on the sensing field.
In this paper, we are presenting the design concept and challenges of such infrastructure. Also, we present
the use of the infrastructure in one possible environmental monitoring application such as forest fire. The
development of such infrastructure will have an impac
INTRODUCTION
Recent advances in wireless communications and electronics have enabled the development of
wireless sensor networks that use low-cost, low-power, multifunctional sensor motes. These tiny
motes design consist of integrated sensing, computing, communication units, and some other
application-dependent units such as power generators and location finding units [1-3]. Such
networks offer economically viable solutions for applications that can be found in different
settings such as industry, military, environment, health, etc. [4, 5]. Sensor motes are generally
designed and programmed to match the needs of the target applications before they are released
to the field. We present WSN mote design that can provide remote software reprogramming and
hardware modification capabilities, which called throughout this paper as “RH-mote”. This type
of mote is not available in existing WSN infrastructure. Therefore, it is crucial to explore the
design and the use of such motes in next-generation WSNs, which require on-field system
modifications. The design and the development of the proposed RH-mote will provide WSNs
with dynamically adaptable feature. Such feature will provide motes with design adjusting
capability to the surrounding environment even after the deployment of the RH-mote on the
sensing field.
RH-MOTE’S DESIGN CONCEPT AND CHALLENGES
Sensor motes in some existing WSNs have the support for software reprogramming capability.
For example, the SOS project at UCLA provides software modifying on individual motes of a
sensor network after the network has been deployed and initialized. The incremental update
ability for new software modules and removed unused software module after network deployment
have been implemented in SOS project [6]. Also, the lightweight virtual machines such as Mate
and modular operating systems such as Contiki are using incremental code updates. Therefore, in
this RH-mote infrastructure project, the focus will be given to the hardware modifications
capability since it is a new feature for WSNs that has not been investigated thoroughly yet [7].
The main design challenges of supporting RH-mote infrastructure development with remote
hardware modifications are as follows:
RH-MOTE INFRASTRUCTURE DEVELOPMENT
The strategy for the RH-mote infrastructure development is based on integrating all RH-mote’s
components on on FPGA chip. The mote’s FPGA chip includes the soft components required for
the mote design such as processor, sensor interfaces, JTAG controller, memory and wireless
transceiver interfaces and controllers. In addition to these soft components, otheroff-the-shelf components such as the temperature/humidity sensor, CMOS pixels sensor,
memory, wireless transceiver, solar unit, and mote’s batteries have been integrated with the soft
components and placed on the RH-mote’s PCB board [Figure 1]. The VHDL language has been
used to design all soft cores used in the mote design such as processor and sensors interfaces.
The main components of the RH-mote are as follow:
WSN PROTOTYPE DEVELOPMENTS
We are developing a WSN prototype to provide a proof-of-concept for using remote hardware
modification and software reprogramming capability of the RH-mote infrastructure in WSN
applications. A small size WSN prototype that has few clusters of 10 motes each will be
developed [Figure 4].
A forest fire monitoring application will be used to demonstrate the use of RH-motes, which can
be modified remotely their soft processing cores on the application field. Each RH-mote has three
sensors: humidity, temperature, and CMOS pixels. The remote hardware modifications capability
of the proposed mote will be used to remotely modify the processing core of each mote to match
the needs of the surrounding application environment. There are different possible scenarios of
using the RH-motes on forest fire monitoring. However, we will use one possible scenario that
CONCLUSION
We presented the concept and the challenges in designing RH-mote that can support remote
hardware and software modifications. The development of such mote infrastructure will have an
impact on advances the research on the real-time remote sensing, heterogeneous WSN, and
WSNs applications. The RH-mote’s infrastructure can be used in Environmental monitoring such
as forest fire applications. Using FPGA chips in RH-motes will consume large power. However,
we propose using a low-cost tiny solar unit to recharge the RH-mote’s batteries. This will provide
long operation time and elevate the drawback for the large power consumption of using FPGA in
the proposed infrastructure.