This document provides an overview of wireless sensor network communication architectures and their design challenges. It describes that wireless sensor networks consist of spatially distributed sensors that cooperatively monitor physical conditions. The key components of sensor nodes are described as well as common communication architectures and protocols used. Some examples of wireless sensor network applications are also mentioned such as environmental monitoring, precision agriculture, and health monitoring. Design challenges for wireless sensor networks include energy efficiency, distributed processing, and operating in harsh environments.

1. An Overview of a Wireless Sensor
Network Communication Architecture
& their Design Challenges
N. R. Pawar1, P. D. Bageshwar#, O. P. Chimankar* & Devraj
Singh$
1Department of Physics, Arts, Commerce & Science College,
Maregaon-445 303, India
#Department of Physics, M. M. College, Darwha-445 202, India
*Department of Physics, RTM Nagpur university, Nagpur-440
033, India
$Department of Applied Physics, Amity School of Engineering &
Technology, New Delhi 110 061, India
Corresponding Author: pawarsir1@gmail.com,
pdbageshwar@gmail.com, dsingh13@amity.edu

2. • Abstract
• In this paper, we investigate the importance of wireless
sensor network communication architecture and
explain the key issues that are faced in the design of
the wireless sensor network monitoring strategy. We
review the communication protocols and algorithms in
MAC layer and network layer, and examine the
standard components in the sensor network
architecture. Based on the survey, we recommend the
multi-hop and cluster based sensor network
communication architecture for the proposed
applications. We further study the MAC layer and
network layer communication protocols for wireless
sensor networks with the applications for wide area
large scale soil moisture estimation, wetlands
monitoring, etc

3. • Introduction:
• Wireless Sensor Networks (WSNs) investigates the properties of
network sensors with wireless communication. The importance of
wireless sensor networks arises from their capability for detailed
monitoring in remote and inaccessible locations where it is not
feasible to install conventional wired infrastructure. Wireless
Sensor Networks play important role in disaster prevention and
relief, environmental monitoring, navigation, logistics tracking,
medical applications, military observation and intelligence
gathering, etc. There are a number of research challenges
associated with wireless sensor communication arising from the
limited capabilities of low cost sensor node hardware and the
common requirement for nodes to operate for long time periods
[1&2]. The distributed nature of wireless sensor networks makes
energy-efficient protocol design particularly challenging. There are
unique problems in self configuration, network discovery, medium
access control and multi-hop routing. Cross-layer design is
required to bring about stable and energy-efficient solutions. The
915 MHz and 2.4 GHz industrial, scientific and medical (ISM) band
has been widely suggested for sensor networks [3].

4. • Wireless Sensor Networks Communication
Architecture:
• A wireless sensor network (WSN) is a wireless network
consisting of spatially distributed autonomous devices
using sensors to cooperatively monitor physical or
environmental conditions, such as temperature, sound,
vibration, pressure, motion or pollutants, at different
locations. Wireless Sensor Networks are networks that
consist of sensors which are distributed in an ad hoc
manner. These sensors work with each other to sense
some physical phenomenon and then the information
gathered is processed to get relevant results. Wireless
sensor networks consist of protocols and algorithms
with self-organizing capabilities.

5. • Wireless Sensor Networks Communication
Architecture:
• A wireless sensor network (WSN) is a wireless
network consisting of spatially distributed
autonomous devices using sensors to cooperatively
monitor physical or environmental conditions, such
as temperature, sound, vibration, pressure, motion
or pollutants, at different locations. Wireless Sensor
Networks are networks that consist of sensors
which are distributed in an ad hoc manner. These
sensors work with each other to sense some
physical phenomenon and then the information
gathered is processed to get relevant results.
Wireless sensor networks consist of protocols and
algorithms with self-organizing capabilities.

6. • Example of WSN:
• Outdoor: WSN Nodes & fitness parameter sensor,
WSN Nodes & fitness parameter sensor
• Indoor: WSN Nodes & vital parameter sensor, WSN
Nodes & fitness parameter sensor
• Service Centre: Operator Network, Home Gateway,
Mobile Gateway

7. • Operations in a Wireless Sensor Network Communication
Architecture:
• A basic sensor node typically comprises of five main
components and they are namely
• controller, memory, sensors and actuators, communication
device and power supply ( Fig.1). A controller is to process all
the relevant data, capable of executing arbitrary code.
Memory is used to store programs and intermediate data.
Sensors and actuators are the actual interface to the physical
world. These devices observe or control physical parameters
of the environment. The communication device sends and
receives information over a wireless channel. And finally, the
power supply is necessary to provide energy. In wireless
sensor networks, power consumption efficiency is one of the
most important design considerations. Therefore, these
intertwined components have to operate and balance the
trade-offs between as small energy consumption as possible
and also the need to fulfill their tasks [4-7].

8. • Microcontrollers used in several wireless sensor
node prototypes are Atmel processor and
• Intel Armstrong processors, etc. In this project, we
have consolidated a list of sensor nodes in the
literature (Table-1). It is noted that mica 2 mote and
mica Z mote, and mica 2 dot motes are appropriate
nodes suitable for large area wetland monitoring
application because of its characteristics. These
three motes operation range can out reached up to
500 feet (152 m), and has the lifetime up to 7 years.

9. • Communication device is used to exchange data
between individual nodes. The communication
medium between the two nodes is through radio
frequencies (wireless medium). Radio frequency-
based communication fits the requirements of most
wireless sensor applications because it provides
relatively long range and high data rates, acceptable
error rates at reasonable energy expenditure, and
does not require line of sight between sender and
receiver.
•

10. • For actual communication, both a transmitter and a
receiver are required in a sensor node.
• The essential task is to convert a bit stream coming
from a microcontroller and convert them to and
from radio waves. As half duplex operation is
recommended in wireless sensor network a
transceiver is generally used. In the transceiver,
circuitry includes modulation, demodulation,
amplifiers, filters, mixers. The table below
summarizes the frequency bands, modulation and
data parameters that could be used in the
communication medium.

11. • The transceiver must provide an interface that
allows the medium access control (MAC)
• layer to initiate frame transmissions and to hand
over the packet from the main memory of the
sensor node into the transceiver (or a byte or a bit
stream, with additional processing required on the
micro controller). In other direction, incoming
packets must be streamed into buffers accessible by
MAC protocol [8&9].
•

12. Sensor node hardware components
MEMORY
CONTROLLER SOURCE/SINKCOMMUNICATION
DEVICE
POWER SUPPLY

13. Phy ( Mhz) Frequency
band(Mhz)
Chip rate
(kchi/s)
Modulation Bit rate Symbol rate
(ksymbol/s)
868/915 868-868.6 300 BPSK 20 20
902-928 600 BPSK 40 40
2450 2400-2483.5 2000 O-QPSK 250 62.5

14. • Characteristics of Wireless Sensor Networks:
• Wireless Sensor Networks mainly consists of
sensors. These sensors are low power, limited
memory, energy constrained due to their small size,
wireless networks can also be deployed in extreme
environmental conditions and may be prone to
enemy attacks and although deployed in an ad hoc
manner they need to be self organized and self
healing and can face constant reconfiguration.

15. • Precision Agriculture: Precision agriculture aims at
making cultural operations more efficient, while
reducing environmental impact. The information
collected from sensors is used to evaluate optimum
sowing density, estimate fertilizers and other inputs
needs, and to more accurately predict crop yields.
• Monitoring Objects:
• (i) Structural Monitoring (ii) Eco-physiology (iii)
Condition-based Maintenance (iv) Medical
Diagnostics (v) Urban terrain mapping.

16. • Applications of Wireless Sensor networks:
• The applications can be divided in three categories:
• Monitoring of an area 2. Monitoring of an objects 3.
Monitoring of both area and objects.
• Monitoring Area:
• (i) Environmental and Habitat Monitoring (ii)
Precision Agriculture (ii) Indoor Climate Control (iv)
Military Surveillance (v) Treaty Verification (vi)
Intelligent Alarms

17. • Condition-based Maintenance:
• (i) Intel fabrication plants (ii) Sensors collect
vibration data, monitor wear and tear; report data
in real-time (iii) Reduces need for a team of
engineers; cutting costs by several orders of
magnitude
• Monitoring Interactions between Objects and
Space:
• (i) Wildlife Habitats (ii) Disaster Management (iii)
Emergency Response (iv) Ubiquitous Computing (v)
Asset Tracking (vi) Health Care (vii) Manufacturing
Process Flows (viii) The Zebra Net Project

18. • Design Challenges:
• Heterogeneity: The devices deployed maybe of
various types and need to collaborate with each
other.
• Distributed Processing: The algorithms need to be
centralized as the processing is carried out on
different nodes
• Low Bandwidth Communication: The data should
be transferred efficiently between sensors

19. • Large Scale Coordination: The sensors need to
coordinate with each other to produce required
results.
• Utilization of Sensors: The sensors should be
utilized in a ways that produce the maximum
performance and use less energy.
• Real Time Computation: The computation should
be done quickly as new data is always being
generated.

20. • Operational Challenges of Wireless Sensor
Networks:
• Energy Efficiency, Limited storage and computation,
Low bandwidth and high error rates, errors in
common wireless communication, noisy
measurements, node failure are expected,
scalability to a large number of sensor nodes and
survivability in harsh environments

21. • Future of WSN:
• In future we can use WSN for:
• Design smart house and office by using Sensors
controlling appliances and electrical devices.
• Health Monitors to detect Glucose, Heart rate,
Cancer detection, Chronic Diseases like artificial
retina & cochlear implants.
• Hospital Sensors to Monitor vital signs, Record
anomalies, etc

22. • Military: Remote deployment of sensors for tactical
monitoring of enemy troop movements.
• Industrial & Commercial to detect Agricultural Crop
Conditions, Inventory Tracking, In-Process Parts
Tracking, Automated Problem Reporting, RFID –
Theft Deterrent and Customer Tracing, Plant
Equipment Maintenance Monitoring, Traffic
Management & Monitoring.
• Future cars could use wireless sensors to handle
Accidents, handle Thefts, etc

23. •THANK YOU
•VERY MUCH
•HAVE A GOOD DAY