CS5530 Mobile/Wireless Systems Introduction Yanyan Zhuang - - PowerPoint PPT Presentation

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Aug 30, 2023 346 likes •657 views

CS5530 Mobile/Wireless Systems Introduction Yanyan Zhuang Department of Computer Science http://www.cs.uccs.edu/~yzhuang UC. Colorado Springs CS5530 Ref. CN5E, NT@UW Intro of Intro Yanyan Zhuang o PhD in network systems o

SLIDE 1

Ref. CN5E, NT@UW

CS5530

CS5530 Mobile/Wireless Systems

Introduction

Yanyan Zhuang

Department of Computer Science http://www.cs.uccs.edu/~yzhuang

UC. Colorado Springs

SLIDE 2

Intro of Intro

Ref. CN5E, NT@UW

2 CS5530

Yanyan Zhuang
PhD in network systems
yzhuang@uccs.edu
Office hours
M/W: an hour after class
F: 11am – 12pm
Blackboard: announcement, schedules

SLIDE 3

Outline

Ref. CN5E, NT@UW

3 CS5530

Why study mobile/wireless systems?
What will you learn?
Lectures, Assignments, Projects, Exams
Course policy
Overview

SLIDE 4

Why study mobile/wireless systems?

Ref. CN5E, NT@UW

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Where does Internet come from?
Computer center à Computer networks à Internet
Wireless
Mobility, flexibility

SLIDE 5

What will you learn?

Ref. CN5E, NT@UW

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How do wireless networks work?
WiFi, cellular, Bluetooth, etc.
No heavy math!
How to program on end-user devices?
iOS
Android

SLIDE 6

Lectures, Assignments, Project, Exams

Ref. CN5E, NT@UW

6 CS5530

Lectures
Monday and Wednesday 4:45PM – 6:00 PM
ENGR 138
Assignments (individual)
iOS/Android programming assignments
Research project (individual or in groups)
Choose a topic that interests you, talk to me before you start
Midterm and Final (online, open-book, limited time)
Midterm TBD, mid/late March (take home)
Final: 5:20 – 7:20 pm, May 10 (in class)

http://www.uccs.edu/Documents/cic/spring%202017/Final%20Exam%20Sc hedule.pdf

SLIDE 7

Course Policy

Ref. CN5E, NT@UW

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Grading scale

Percentage Grade 90 - 100 A 87 - 89 A- 84- 86 B+ 80 - 83 B 75 - 79 C+ 70 - 74 C 65 - 69 D+ 60 - 64 D Below 60 F

SLIDE 8

Course Policy (cont.)

Ref. CN5E, NT@UW

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Grading percentage
Assignments: 40%
Research project: 20%
Midterm: 20%
Final exam: 20%

SLIDE 9

Where to get help?

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Q&A in class
Office hours
M/W one hour after class 6-7pm
F: 11:00am -- 12:00pm
By appointment
ENGR 184

SLIDE 10

Ref. CN5E, NT@UW

10 CS5530

Overview

SLIDE 11

What is a Wireless Network

Ref. CN5E, NT@UW

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First, what is a network?
Computer networks

} A large number of separate but interconnected computers } The connection: via a copper wire, fiber optics, microwaves, infrared,

satellites, and so on

Internet

} The most well-known network of networks

SLIDE 12

Where did Internet come from?

Ref. CN5E, NT@UW

12 CS5530

ARPANET (1966-1967): Advanced Research Projects

Agency Network

Funded by Advanced Research Projects Agency (ARPA) of

United States Department of Defense

Goal: network academic computers (UCLA, SRI, UCSB,

Utah -- first nodes in 1969)

1971: ~20 ARPANET nodes

SLIDE 13

Where did Internet come from?

Ref. CN5E, NT@UW

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Rough sketch: late 1960s

SLIDE 14

Ref. MOS4E, OS@Austin, Columbia, UWisc
UC. Colorado Springs

CS4500/5500

1970s to 1980s: ARPANET transitioned to TCP/IP

SLIDE 15

Growth of Internet Hosts

Ref. CN5E, NT@UW

15 CS5530

SLIDE 16

What is a Wireless Network (cont.)

Ref. CN5E, NT@UW

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Use of networks
Business, home use
Mobile users

} People on the go want to do all things they do at home and in office } Mobile connectivity

¨ Cellular, WiFi (IEEE 802.11)

} Different mobile systems

¨ Smartphones/tablets/smart watch ¨ GPS ¨ RFID (Radio-Frequency IDentification)

SLIDE 17

What is a Wireless Network (cont.)

Ref. CN5E, NT@UW

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Some other wireless networks
Sensor networks

} Made up of nodes that gather and wirelessly relay information they

sense about the state of the physical world

} The nodes may be cars or phones, or may be separate devices

¨ Car’s OBD sensors ¨ Separate devices

¨ accelerometers, barometers, ocean bottom seismometers, pressure recorders

and hydrophone

SLIDE 18

Network Reference Model

Ref. CN5E, NT@UW

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A four layer model based on experience

4 Application

– Programs that use network service

3 Transport

– Provides end-to-end data delivery

2 Internet

– Send packets over multiple networks

1 Link

– Send frames over a link

3 Transport

– Provides end-to-end data delivery

SLIDE 19

Network Reference Model (cont.)

Ref. CN5E, NT@UW

19 CS5530

A four layer model based on experience

4 Application 3 Transport 2 Internet 1 Link

Ethernet 802.11 IP TCP UDP HTTP SMTP RTP DNS 3G DSL Cable

network layer Every Internet device must speak!

SLIDE 20

LAN and WLAN

Ref. CN5E, NT@UW

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The standard for wireless LANs is called IEEE 802.11, popularly known as WiFi Wireless router / Base station

SLIDE 21

Wireless vs. Wired

Ref. CN5E, NT@UW

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Link layer
Medium: open air
No wiring required
Less secure than wired networks
It’s a lot more difficult for unauthorized eavesdroppers and other

snoops to monitor data in a wired network

4 Application 3 Transport 2 Internet 1 Link

Ethernet 802.11 IP TCP UDP HTTP SMTP RTP DNS 3G DSL Cable

SLIDE 22

Wireless vs. Wired

Ref. CN5E, NT@UW

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Advantage
Allows mobility
Much cheaper and easier to deploy, change, and upgrade
Disadvantage
Exposed (unshielded) medium

}

Susceptible to physical phenomena (interference)

}

More errors

Slower data rates for longer distances
Security: anyone in range hears transmission

SLIDE 23

Wireless Standards

Ref. CN5E, NT@UW

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Cellular
2G: GSM, CDMA
3G: CDMA2000, WCDMA, TD-SCDMA
4G/5G/LTE
IEEE 802.11
a: 5.0Ghz band, 54Mbps (25 Mbps operating rate)
b: 2.4Ghz band, 11Mbps (4.5 Mbps operating rate)
g: 2.4Ghz, 54Mbps (19 Mbps operating rate)
Other versions (802.11n, p, etc.)
IEEE 802.15: low powered wireless
802.15.1: 2.4Ghz, 2.1 Mbps (Bluetooth)
802.15.4: 2.4Ghz, 250 Kbps (Sensor Networks)

SLIDE 24

Wireless Link Characteristics

Ref. CN5E, NT@UW

24 CS5530

SLIDE 25

Wireless Transmission Range

Ref. CN5E, NT@UW

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1. Transmission power
2. Signal-to-noise ratio

The range that the receiver is just able to receive/decode the signal

SLIDE 26

A Wireless Link?

Ref. CN5E, NT@UW

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SLIDE 27

A Wireless Link!

Ref. CN5E, NT@UW

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SLIDE 28

Some other issues

Ref. CN5E, NT@UW

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Hidden terminals
A and C can both send to B but can’t hear each
ther
A is a hidden terminal for C and vice versa

A B C

SLIDE 29

Some other issues (cont.)

Ref. CN5E, NT@UW

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Exposed terminals
Exposed node: B sends a packet to A; C hears this

and decides not to send a packet to D (despite that this will not cause interference)

A B C D

SLIDE 30

Summary

Ref. CN5E, NT@UW

30 CS5530

What is a network
Different kinds of wireless networks
Wireless standards
Issues with wireless networks