Wireless Networks introduction

1. Wireless Networks
Lecture 1
Introduction
(2025-2026)

2. Midterm exam 20 marks
Presentation 10 marks
Optional (activities)
(questions during lectures)
10 marks

3. Wireless networks
Feature Wired Network Wireless Network
Medium Uses cables (Ethernet, fiber optic) Air
Data Rate High (up to Tbps) Lower (up to several Gbps)
Reliability Very stable and consistent
Affected by interference and
obstacles
Mobility Limited High
Installation Requires physical cabling Easy to set up, no cables
Cost Higher initial installation cost Lower setup cost
Security
More secure (physical access
needed)
Needs strong encryption
Interference Minimal Can be high (other devices, walls)
Maintenance Easy to control and manage Harder due to signal issues
Use Cases Data centers, offices Homes, mobile devices.

4. Wireless Impact
• Shrinks the world
• Always on
• Always connected
• Changes the way people communicate
– Social networking
• Global wireless network
Introduction 1-4

5. Some Milestones in Wireless Communications
Introduction 1-5
AM

6. 1930s–1950s: The Beginning of Wireless Broadcasting
Introduction 1-6
• Technologies: Shortwave radio → AM radio
→ FM radio → Black-and-
white TV
low frequencies (HF–VHF)
and analog signals.
• Frequencies :
• The main purpose was broadcasting—one
transmitter sending programs to many
receivers at home.
• It was the radio and early television age, with
centralized broadcast networks.

7. 1960s–1970s: The Start of Mobile and Satellite
Communication
Introduction 1-7
• Technologies:
Mobile two-way radios, Color TV,
Communication satellites, Terrestrial
microwave links
• Mobile two-way radios: ~30–300 MHz
(VHF) and 300–900 MHz (UHF).
• Microwave and satellite links: 1–10 GHz
(SHF band).
• Frequencies :
• First professional mobile radios (used by police, taxis, etc.).
• Color television became common.
• Satellite experiments began, allowing international
communication.
• Microwave links were used for long-distance transmission
between cities.

8. 1980s: The Birth of Personal Wireless Devices
Introduction 1-8
• Technologies: Cordless phones, Early cellular phones
• Cordless phones: around 900 MHz
(UHF).
• Early cellular networks: around 800–
900 MHz.
• Frequencies :
• Wireless communication personal use.
• The first cellular systems were developed, introducing the
cell concept (dividing areas into smaller zones).
• This allowed mobile users to move between areas using a
process called handoff (switching from one cell tower to
another).

9. 1990s: The Rise of Digital and Wireless Internet
Introduction 1-9
• Technologies: Early Wi-Fi, Advanced cellular
networks
• Frequencies :
• Digital communication replaced analog systems,
improving quality and efficiency.
• Wi-Fi appeared, creating local wireless networks for
computers.
• Cell phones became smaller and more popular, and
mobile Internet began to grow.
•Wi-Fi: 2.4 GHz (ISM band).
•Cellular (2G/3G): 800 MHz to 2.1 GHz.

10. 2000s: The Mobile Internet
Introduction 1-10
• Technologies: 3G (CDMA/UMTS), 4G LTE,
ZigBee
• Frequencies :
• Focus on mobile data services—browsing, video, email, and
apps.
• Networks became faster and more complex, using OFDM and
MIMO technologies for high-speed communication.
• ZigBee appeared for low-power IoT devices such as sensors
and smart homes.
• 3G (CDMA/UMTS): 800 MHz to 2.1
GHz.
• 4G LTE: 700 MHz to 2.6 GHz.
• ZigBee (IoT): 2.4 GHz (low-power ISM
band).

11. 2010s–2020s: High-Speed, Smart, and Connected
World
Introduction 1-11
• Technologies: LTE-Advanced, 5G, mmWave,
IoT, Terahertz, Optical links
• Frequencies :
• 5G introduced mmWave frequencies for ultra-fast
connections and very low delay (latency).
• Massive MIMO and dense small-cell networks improved
performance in cities.
• The Internet of Things (IoT) became common—many devices
connected using different protocols.
• 4G LTE-Advanced: 700 MHz – 3.5 GHz.
• 5G mmWave: 24 GHz – 100 GHz.
• IoT: 700 MHz – 2.4 GHz (varies by protocol)

12. 2021–Present: The Era of Intelligent and Ultra-Fast
Connectivity
Introduction 1-12
• Technologies:
5G Advanced, 6G, AI-driven
networks, Growth of satellite Internet
systems like Starlink
• Frequencies :
• 5G Advanced: 3.5–7 GHz and mmWave bands (24–100
GHz).
• Wi-Fi 6/7: 2.4 GHz, 5 GHz, and 6 GHz bands.
• Future 6G research: 100 GHz–1 THz range (sub-
terahertz).
• LEO satellites: 12–30 GHz (Ku/Ka bands).

13. Summary
Period Key Technologies Frequency Range Main Features
1930s–1950s
AM/FM Radio, Black &
White TV
3–300 MHz (HF–
VHF)
Analog broadcasting,
wide coverage
1960s–1970s
Two-way radio, Color
TV, Microwave,
Satellites
30 MHz–10 GHz
Start of mobile &
satellite links
1980s
Cordless phones, Early
Cellular
800–900 MHz
First personal wireless
devices, cellular
concept
1990s Wi-Fi, 2G/3G Cellular 800 MHz–2.4 GHz
Digital communication,
wireless Internet begins
2000s 3G, 4G LTE, ZigBee 700 MHz–2.6 GHz
Mobile Internet, IoT
emerges
2010s–2020s 4G LTE-A, 5G, IoT
700 MHz–100
GHz
High speed, low
latency, mmWave
2021–Present
5G Advanced, 6G
research, Wi-Fi 7, Smart
IoT
3.5 GHz–1 THz
Intelligent, ultra-fast,
AI-based networks

14. Wireless Comes of Age
• Guglielmo Marconi invented the wireless telegraph in
1896
– Communication by encoding alphanumeric characters in
analog signal
– Sent telegraphic signals across the Atlantic Ocean
• Communications satellites launched in 1960s
• Advances in wireless technology
– Radio, television, mobile telephone, mobile data,
communication satellites
• More recently
– Wireless networking, cellular technology, mobile apps,
Internet of Things
Introduction 1-14

15. Cellular telephone
• Started as a replacement to the wired telephone
• Early generations offered voice and limited data
• Current third and fourth generation systems
– Voice
– Texting
– Social networking
– Mobile apps
– Mobile Web
– Mobile commerce
– Video streaming
Introduction 1-15

16. Classification of wireless networks
• Wireless body area networks (BAN)
• Wireless personal area networks (PAN)
• Wireless local area networks (LAN)
• Wireless metropolitan area networks (MAN)
• Wireless wide area networks such as GSM and CDMA
cellular networks (WAN)
• Satellite networks and access networks broadband

17. Classification of wireless networks
(Contd..)

18. Wireless Body Area Network (WBAN)
⚫ Max. signal range 2 meters
Interconnecting respective devices within the surface of the body

19. Wireless Personal Area Network (WPAN)
• Max signal range
(around 10 m).
• Used for personal
devices: phones,
headsets, watches.
• Examples:
Bluetooth, ZigBee,
Infrared, Ultra-Wide
Band (UWB), Laser,
Free Space Optics
(FSO).

20. Wireless Local Area Network (WLAN)
• Signal range is
≈100 meters.
• Used in homes,
schools, and
offices.
• Example: Wi-Fi
(IEEE 802.11
standards).

22. An example of wireless LAN
Work
Station
Work
Station
Work
Station
Work
Station
Work
Station
Printer
Server
Access
Point
Access
Point
Access
Point
Access
Point
Access
Point
Access
Point
Laptop Laptop Laptop
Laptop
Laptop
Work
Station

23. Wireless Metropolitan Area Network
(WMAN)
• Signal range of
approximately 5 km
to 20 km (recently up
to 50 km)
• Often called
Worldwide for
Microwave Access
(WiMAX or IEEE
802.16)
• Use cellular
network
technologies such
as WI-MAX, GSM,
GPRS, 3G

24. Wireless network architecture
• Logical architecture
Introduction 1-24
• Physical architecture
: describes the abstract,
invisible structure of how data is exchanged.
: describes the details of
the hardware components and their real-world
connections.

25. Wireless network architecture
Introduction 1-25
Logical Architecture Physical Architecture
Focus "How does the network
operate?".
Defines the communication
protocols, addressing schemes,
and data flow.
"What and how is the network built with?
Specifies the actual hardware, such as access
points, antennas, and network interface cards,
and their physical connections.
Components Includes software-based
elements like:
• Protocols: TCP/IP, UDP,
etc.
• Addressing: IP addresses
and MAC addresses.
• Services: DHCP (Dynamic
Host Configuration
Protocol), DNS (Domain
Name System).
• Security Policies: Firewalls
and access controls.
Includes hardware-based elements like:
• Access Points (APs): Transmit and receive
wireless signals.
• Antennas: Used by APs and devices to send
signals.
• Network Interface Cards (NICs): Allow end
devices (laptops, phones) to connect
wirelessly.
• Wireless Controllers: Centralized devices
for managing multiple APs in large
networks.
• Wireless Bridges/Repeaters: Extend wireless
signal range.

26. Wireless network mode
• Wireless network structure is the design and
organization of a wireless network, which can be
structured in different ways, such as:
Introduction 1-26
• The Infrastructure Mode (using access points)
– Infrastructure mode is the most common, connecting
devices to an access point.
• Ad Hoc Mode (direct peer-to-peer communication).
– Ad hoc is useful for quick, temporary connections where
no access point is available

27. Feature Infrastructure Mode Ad Hoc Mode
Definition
Devices communicate through
a central device (Access Point
or Base Station).
Devices communicate directly
with each other without any
central control.
Control
Managed and coordinated by a
central node (router or cellular
tower).
Each node acts as both a sender
and receiver; no central
coordination.
Topology Star or hierarchical structure. Mesh or peer-to-peer structure.
Range
Determined by multiple access
points
Restricted to the range of
individual devices on the network
Scalability
Easily scalable with more APs
or cells.
Harder to scale; performance
drops as more nodes join.
Reliability
More reliable (central
coordination and
authentication).
Less reliable (depends on nodes’
cooperation).
Security
Easier to secure (central
authentication).
Harder to secure; no fixed control
point.
Example
Wi-Fi networks with routers,
Cellular networks (2G–5G).
Bluetooth peer-to-peer, Ad hoc,
MANETs, VANETs, Wi-Fi Direct.

28. Cellular network
It consists of mobile hosts, fixed hosts, access stations (BS),
core network to support mobility and switching.
• 11
million
users in
1990
• Over 7
billion
today

29. Basics: Structure
Cells Different
Frequencies or
Codes
Base Station Fixed
transceiver
Mobile Station Distributed
transceivers
Downlink
Uplink
Handoff
Multiple Access

30. Cellular network Generations
• Generations
– 1G – Analog
Introduction 1-31
– 5G –Millimeter wave
(Massive MIMO)
• 20 Gbps
• Network Slicing
– 2G – Digital voice
• Voice services with some moderate rate data
services
– 3G – Packet networks
• Universal Mobile Phone Service (UMTS)
• CDMA2000
– 4G – New wireless approach (OFDM)
• Higher spectral efficiency
• 100 Mbps for high mobility users
• 1 Gbps for low mobility access
• Long Term Evolution (LTE) and LTE-
Advanced
– 6G –Space–Air–
Ground–Sea networks
• 1 Tbps
• Li-Fi

32. Ad hoc networks
An ad hoc network is one
where devices connect directly
to each other without any
dedicated network devices.
– Do not need backbone
infrastructure support
– Are easy to deploy
– Useful when infrastructure is
absent, destroyed, or
impractical

33. Mobile device revolution
• Originally just mobile phones
• Today’s devices
– Multi-megabit Internet access
– Mobile apps
– High megapixel digital cameras
– Tablets provide balance between smartphones and PCs
– Better use of spectrum
– Decreased costs
– Access to multiple types of wireless networks
• Bluetooth(Short distance), Wi-Fi(Local areas), 3G-4G (Long
distance) Introduction 1-34

34. Discussion Questions
1. What is a wireless network?
2. What advantages do wireless networks have over wired ones?
3. What are the main classifications of wireless networks based on the
range area?
4. How does a WLAN differ from a WPAN in range and use?
5. What is the role of an access point in an infrastructure mode?
6. Explain the wireless network architecture. (How do logical and
physical architectures differ?)
7. What are the wireless network modes?
8. Compare the infrastructure mode and ad hoc mode.
9. What are the main components of the cellular network?
10. Why are cellular networks considered infrastructure-based
networks?
11. What are the main features of 3G, 4G, and 5G networks?
12. How can ad hoc networks be useful during disasters?