Chapter five

Introduction to Wireless
Communication Systems and
Technologies

By Workie G.
 Outline
 Wireless communication

 Evolution of wireless communications

 Trends in wireless communications - 1st, 2nd,

and 3rd, 4th, 5th generation systems
 Cellular network

 Sensor network

 Ad hock network

 Design issues and challenges

 Design factor
 What is communication
 Communication is a field of study that involves the
transmission and the reception of information
between people or group of individuals.
 The term communication can be used to refer to the
transfer of any kind of information from one person to
another.
 This includes verbal, non-verbal, written or electronic
message.
 what is wireless
communication?
 Wireless communications is the transmission of voice
and data without cable or wires.
 In place of a physical connection, data travels through
electromagnetic signals broadcast from sending facilities
to intermediate and end-user devices.
 Wireless Communication is a method of transmitting
information from one point to other, without using any
connection like wires, cables or any physical medium.
 Cont.…
 A communication system is a combination of
devices and techniques used to transmit information
from one place to another.
 Generally, in a communication system, information is
transmitted from transmitter to receiver that are
placed over a limited distance.
 Examples of communication technologies include
wired phones, radios, televisions, computer
networks and mobile phones.
 Cont…

 Communication Systems can be Wired or

Wireless and the medium used for communication
can be Guided or Unguided.
 In Wired Communication, the medium is a
physical path like Co-axial Cables, Twisted Pair
Cables and Optical Fiber Links etc.
 which guides the signal to propagate from one point
to other. Such type of medium is called Guided
Medium.
 Cont..
 Wireless Communication doesn’t require any
physical medium but propagates the signal through
space.
 Since, space only allows for signal transmission
without any guidance, the medium used in Wireless
Communication is called Unguided Medium.
 Cont…
 If there is no physical medium, then how does wireless
communication transmit signals? Even though there are
no cables used in wireless communication, the
transmission and reception of signals is accomplished with
Antennas.
 Antennas are electrical devices that transform the
electrical signals to radio signals in the form of
Electromagnetic (EM) Waves and vice versa.
 These Electromagnetic Waves propagates through space.
Hence, both transmitter and receiver consists of an
antenna.
 Evolution of wireless
communications

 The history of the wireless communications

started with the understanding of magnetic
and electric properties observed during the
early days by the Chinese, Roman and Greek
cultures and experiments carried out in the
17th and 18th centuries.
 A short history of wireless communication:
 Trends in wireless communications -
1st, 2nd, and 3rd, 4th, 5th generation
systems
 The trends in wireless communication are focused
on:
expanding connectivity, increasing speeds, and
enabling new technologies such as
 5G,
 IoT,
 AI,
 edge computing, and
 augmented reality.
 From private 5G networks to the exploration of
quantum communication.
 cellular network

 A cellular network referred to as a mobile network,

is a type of communication system that enables
wireless communication between mobile devices.
 The cellular network is a wireless digital that is
made up of cells that are served by transceivers
called base stations.
 The final stage of connectivity is achieved by
segmenting the comprehensive service area into
several compact zones, each called a cell.
 Cellular network

 A stationary transceiver, known as a cell

site or base station, provides service in
each cell.
 The cell site links to the primary network
infrastructure, employing either a wireless or
wired connection.
Cont.…
 Sensor Networks
A sensor network is a system of spatially
distributed sensors that collect data from the
environment and transmit it to a central
processing unit for analysis.
 These networks are designed to monitor physical or
environmental conditions such as temperature,
humidity, pressure, motion, or light intensity.
 Sensor Networks
 Sensor networks are a core component of the
Internet of Things (IoT), enabling devices to collect
and exchange data, often wirelessly, to make
informed decisions in real-time.
 They can be used in a wide range of applications,
from industrial monitoring to environmental
sensing and health applications.
 Types of Sensor Networks
1. Wireless Sensor Networks (WSNs):
WSNs consist of sensor nodes that communicate
wirelessly to exchange data.
These networks are particularly useful in remote or
difficult-to-access environments where wiring is not
feasible.
Applications: Environmental monitoring (e.g., forest
fires, air quality), industrial monitoring (e.g., machine
health), agricultural monitoring (e.g., soil moisture), and
smart cities.
 Types of Sensor Networks
2. Body Area Networks (BANs):
A Body Area Network is a type of sensor network designed to
monitor and collect data from the human body.
This often includes devices like wearable sensors,
smartwatches, and health-monitoring devices.
Applications: Healthcare (e.g., heart rate monitoring, glucose
levels, activity tracking), fitness monitoring, and elderly care.
 Types of Sensor Networks
3.Smart Home and Building Sensor Networks
Smart homes utilize sensor networks to improve comfort,
security, and energy efficiency.
These networks include sensors for temperature, lighting,
security (e.g., cameras, motion detectors), and even smart
appliances.
Applications: Home automation (e.g., lighting, HVAC control),
security systems, energy management, and home health
monitoring.
 Types of Sensor Networks
4.Industrial Sensor Networks:
Industrial sensor networks are used in manufacturing
environments for monitoring equipment, detecting faults, and
ensuring efficient operations.
Applications: Predictive maintenance, equipment monitoring,
energy consumption monitoring, and safety systems (e.g., gas
leak detection).
 Applications of Sensor Networks
1. Environmental Monitoring
2. Healthcare
3. Smart Agriculture
4. Industrial IoT (IoT)
5. Military and Defense
 Challenges in Sensor Networks
1. Power Consumption:
2. Data Overload:
3. Network Scalability:
4. Security and Privacy:
5. Interference and Reliability:
 Ad hoc Network
 An ad hoc network is a type of network that is formed
temporarily without a central infrastructure or pre-
existing setup.
 It allows devices to communicate with each other directly,
often in situations where traditional network infrastructure (like
routers, access points, or servers) isn't available or feasible.
 The primary advantage of ad hoc networks is flexibility
and ease of setup without the need for external
infrastructure, but they can also face challenges in terms of
stability, scalability, and security.
 Characteristics of Ad hoc Network

 Temporary and Spontaneous: Devices in an ad hoc network

can form and dissolve the network dynamically, based on need.
 No Centralized Control: There is no central server or router
controlling the network. Devices communicate with one another
in a peer-to-peer fashion.
 Self-organizing: The devices in an ad hoc network can
automatically discover other devices, manage routing, and
adjust as devices join or leave the network.
 Mobile: Ad hoc networks are particularly useful in mobile or
wireless environments, where devices such as smartphones,
laptops, or sensors can communicate directly without needing
fixed infrastructure.
 Examples of Ad Hoc Networks

 Mobile Ad Hoc Networks (MANETs): These are networks of

mobile devices (like smartphones or laptops) that communicate
directly with each other.
 Wireless Sensor Networks: A collection of sensors or devices
that communicate with each other for data collection and
monitoring without needing centralized control.
 Emergency Communication Networks: In scenarios like
natural disasters or military operations, ad hoc networks are
quickly set up to provide communication among responders.
 Design issues and challenges
 Designing a wireless communication system involves various
challenges and issues due to the nature of wireless
transmission.
 Unlike wired systems, wireless communication systems
must contend with environmental factors, interference,
mobility, and bandwidth constraints.
 Here are some of the main issues and challenges in wireless
communication design:
 Design issues and challenges
1. Signal Propagation and Path Loss Challenge:
 Wireless signals degrade as they travel through space,
leading to path loss.
 This loss can be affected by distance, obstacles (such as
buildings or trees), terrain, and atmospheric conditions.
 Design Consideration:
 Designing efficient transmission power and coverage areas is
crucial to reduce path loss.
 Smart antennas and beamforming can help improve signal
strength and coverage.
 Design issues and challenges
2.InterferenceChallenge:
Wireless communication systems often face interference from
other devices operating on the same or overlapping frequency
bands.
This can lead to degraded performance, dropped connections,
and poor signal quality.
Design Consideration:
Frequency planning, channel allocation, and error-correcting
codes can help mitigate interference.
Using spread spectrum techniques like CDMA (Code Division
Multiple Access) also helps reduce interference.
 Design issues and challenges
3. Multipath Propagation Challenge:
In wireless communication, signals often take multiple paths to
reach the receiver due to reflections off buildings, trees, or other
objects.
This can lead to multipath interference, where multiple versions
of the signal arrive at slightly different times, causing distortion.
Design Consideration:
Diversity techniques, such as spatial diversity (multiple
antennas) and frequency diversity, can help combat multipath
effects.
Equalizers and adaptive modulation also play a role in handling
these issues.
 Design issues and challenges
4. Limited Bandwidth
 Challenge: Wireless communication systems operate over a
limited amount of frequency spectrum, which is shared among
multiple users and devices.
This results in bandwidth limitations and congestion in high-
density environments.
Design Consideration:
Efficient use of bandwidth is critical.
Techniques like frequency reuse, dynamic spectrum allocation,
and compression are employed to maximize bandwidth
efficiency.
 Design issues and challenges
5. Mobility
Challenge: In mobile wireless networks (e.g., cellular
networks, vehicular networks), devices are constantly moving,
leading to changes in signal strength and quality.
Handovers between different network cells or access points
can cause interruptions in service.
Design Consideration:
Handover management and location management protocols
are needed to maintain uninterrupted communication while
ensuring that devices can switch seamlessly between network
coverage areas.
 Design issues and challenges
6. Security
Challenge: Wireless networks are more vulnerable to
eavesdropping, unauthorized access, and interference than
wired networks. Security becomes a major concern, especially in
public networks.
Design Consideration:
Robust encryption, authentication, and access control
mechanisms are essential to secure communication.
Virtual private networks (VPNs) and secure protocols such as
SSL/TLS and WPA3 for Wi-Fi also help safeguard data.
 Design issues and challenges
7. Power Consumption
Challenge: Mobile and wireless devices, such as sensors,
smartphones, and IoT devices, often rely on battery power.
Efficient power usage is a critical challenge, especially in energy-
constrained devices.
Design Consideration:
Power-efficient protocols, energy harvesting, sleep modes, and
low-power hardware design are important to extend battery life
and reduce energy consumption.
 Design issues and challenges
8. Latency
Challenge: Wireless communication can experience higher
latency compared to wired systems due to factors like
propagation delay, signal processing time, and network
congestion.
Design Consideration:
Techniques like Quality of Service (QoS), traffic prioritization,
and low-latency routing protocols can help minimize latency and
improve the user experience.
 Design issues and challenges
9. Scalability
Challenge: Wireless networks need to support a growing
number of devices, particularly with the rise of IoT (Internet of
Things). Managing communication between millions of devices
can be challenging in terms of network congestion, interference,
and data throughput.
Design Consideration:
Network planning and hierarchical network architectures (like
5G network slicing) are necessary to ensure that the network can
scale and handle increased traffic without compromising
performance.
 Design issues and challenges
10. Channel Estimation and Equalization
Challenge: Accurate channel estimation is essential for
efficient communication, especially in environments with
multipath propagation and fading.
Errors in channel estimation can lead to poor data reception
and higher error rates.
Design Consideration:
Advanced techniques such as MIMO (Multiple Input Multiple
Output) systems, adaptive modulation and coding, and channel
equalization are used to improve reception and mitigate fading
effects.
 Design issues and challenges
11. Network Management
Challenge: Managing a wireless network, particularly in a
dynamic environment with mobile devices, requires advanced
protocols for network discovery, traffic routing, and load
balancing.
Design Consideration: Self-organizing networks, automated
optimization, and machine learning-based management systems
are emerging solutions for handling network complexities.
 Design factors
 When designing a wireless communication system,
several design factors must be carefully considered to
ensure:
 the system operates efficiently, meets user
requirements, and provides a reliable and secure service.
 Here are the primary design factors that influence wireless
communication systems:
 Design factors
1. Frequency Spectrum
Consideration: The availability of frequency bands plays a
significant role in wireless communication.
The spectrum is often limited and regulated, so efficient
usage of the available spectrum is critical.
Design Impact: The choice of frequency band impacts the
data rate, coverage area, interference levels, and propagation
characteristics.
For example, lower frequencies (like those used in 4G and 5G
networks) have better coverage but lower data rates, while
higher frequencies can support faster speeds but have shorter
range.
 Design factors
2. Transmission Power
Consideration: The transmission power determines how far
the signal can travel and how well it can penetrate obstacles.
Design Impact: High transmission power can increase the
coverage area, but it may also lead to interference with other
systems.
Power efficiency is a significant factor, particularly for mobile
and battery-powered devices.
 Design factors
3. Channel Bandwidth
Consideration: The bandwidth of the channel determines how
much data can be transmitted in a given time. Bandwidth also
influences the signal quality and interference levels.
Design Impact: Wider bandwidth supports higher data rates
and better overall performance, but it can also lead to more
interference.
The system needs to adapt to different bandwidth conditions
depending on the environment (e.g., urban, rural, or indoor).
 Design factors
4. Latency
Consideration: Latency refers to the delay in signal
transmission and reception.
For applications like real-time communication, gaming, or
autonomous vehicles, low latency is essential.
Design Impact: Reducing latency involves optimizing routing,
reducing signal processing time, and managing network
congestion.
Low-latency protocols and edge computing can help
reduce delays.
 Design factors
5. Security and Privacy
Consideration: Wireless networks are more vulnerable to
attacks such as eavesdropping, unauthorized access, and
denial of service (DoS) compared to wired networks.
Design Impact: Encryption, authentication, and secure
protocols (e.g., SSL/TLS, WPA3 for Wi-Fi) must be implemented
to protect the integrity and privacy of the data being
transmitted.
 Design factors
6. Interference Management
Consideration: Interference can come from multiple sources,
including other wireless networks, electronic devices, and
environmental factors.
Design Impact: Techniques like frequency hopping,
channel coding, interference cancellation, and spatial
filtering help manage and minimize interference in wireless
systems.
 Design factors
7. Cost and Infrastructure
Consideration: The cost of setting up and maintaining the
network infrastructure is a significant design factor, particularly
for large-scale deployments like cellular networks or IoT systems.
Design Impact: The design should balance the trade-offs
between cost, coverage, and performance.
For instance, 5G networks require significant infrastructure
investments but offer high data rates,
while LoRaWAN offers low-cost, long-range communication
for IoT with lower data rates.
Thanks
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