l1-intro and overview -...

Copyright © 2011, Dr. Dharma P. Agrawal and Dr. Qing-An Zeng. All rights reserved 1

Chapter 1

INTRODUCTION

Course Overview

2

n  Introduction

n  Fundamentals of wireless channels

n  Cellular networks (3G, LTE, LTE-A)

n  IEEE 802.11 based WLAN (WiFi)

n  NS-3 network simulator

Today’s Lecture

3

n  Interesting ICT (Information and Communications Technology) statistics

n  Recent trends in ICT

n  Wireless networks

n  Challenges in wireless network service

ICT Statistics (ITIF, 2013)

4

n  Creates high-paying jobs n  IT workers salary: $78,584/yr, average worker: $45,230/yr

n  Comprises a significant share of GDP n  6% of global GDP (2010)

n  Drives productivity and GDP growth n  21% of GDP growth from 2006 to 2011 across 13 leading

economies n  Helps build high-growth companies

n  330 of 500 fastest growing companies are in IT industry n  88% of 500 most popular mobile apps were developed by small

businesses, most with fewer than 10 employees

n  Refer to PDF for other details

Recent Trends: Big Data

5

n  Definition (Wikipedia) n  Any collection of data so large and complex that it becomes

difficult to process using on-hand data management tools or traditional data processing applications

n  Example

http://www.ibmbigdatahub.com/presentation/big-data-retail-examples-action

Recent Trends: Cloud Computing

6

n  Definition (Wikipedia) n  Delivery of computing as a service rather than a product

whereby shared resources, software, and information are provided to computers and other devices as a utility over a network

n  Examples n  Amazon Web Service (AWS), iCloud, sCloud

Recent Trends: Internet of Things (IoT)

7

n  Definition (Wikipedia) n  Interconnection of uniquely identifiable embedded computing-

like devices within the existing Internet infrastructure

IoT is essentially a sensor network

Recent Trends: Software Defined Networking (SDN)

8

n  Software Defined Network (SDN) n  A new approach to designing, building and managing networks

that separates control (brain) and data (muscle) planes to make it easy to optimize each

Network Opera,ng System Global Network Map

Control Program

Software

Very simple hardware OpenFlow

Picture from Nick McKeown

Chapter 6 Wireless and Mobile Networks

Computer Networking: A Top Down Approach 6th edition Jim Kurose, Keith Ross Addison-Wesley March 2012

A note on the use of these ppt slides: We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you see the animations; and can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following: v  If you use these slides (e.g., in a class) that you mention their source

(after all, we’d like people to use our book!) v  If you post any slides on a www site, that you note that they are adapted

from (or perhaps identical to) our slides, and note our copyright of this material.

Thanks and enjoy! JFK/KWR All material copyright 1996-2012 J.F Kurose and K.W. Ross, All Rights Reserved

Wireless, Mobile Networks 6-9


Ch. 6: Wireless and Mobile Networks Background: v  # wireless (mobile) phone subscribers now exceeds #

wired phone subscribers (5-to-1)! v  # wireless Internet-connected devices equals #

wireline Internet-connected devices §  laptops, Internet-enabled phones promise anytime untethered

Internet access

v  two important (but different) challenges §  wireless: communication over wireless link §  mobility: handling the mobile user who changes point of

attachment to network


Chapter 6 outline

6.1 Introduction

Wireless 6.2 Wireless links,

characteristics §  CDMA

6.3 IEEE 802.11 wireless LANs (“Wi-Fi”)

6.4 Cellular Internet Access §  architecture §  standards (e.g., GSM)

Mobility 6.5 Principles: addressing and

routing to mobile users 6.6 Mobile IP 6.7 Handling mobility in

cellular networks 6.8 Mobility and higher-layer

protocols

6.9 Summary


Elements of a wireless network

network infrastructure


wireless hosts v  laptop, smartphone v  run applications v  may be stationary (non-

mobile) or mobile §  wireless does not always

mean mobility




base station v  typically connected to

wired network v  relay - responsible for

sending packets between wired network and wireless host(s) in its “area” §  e.g., cell towers,

802.11 access points




wireless link v  typically used to connect

mobile(s) to base station v  also used as backbone

link v  multiple access protocol

coordinates link access v  various data rates,

transmission distance




Characteristics of selected wireless links

Indoor 10-30m

Outdoor 50-200m

Mid-range outdoor

200m – 4 Km

Long-range outdoor

5Km – 20 Km

.056

.384

1

4

5-11

54

2G: IS-95, CDMA, GSM

2.5G: UMTS/WCDMA, CDMA2000

802.15

802.11b

802.11a,g

3G: UMTS/WCDMA-HSPDA, CDMA2000-1xEVDO

4G: LTWE WIMAX

802.11a,g point-to-point

200 802.11n

Dat

a ra

te (M

bps)


infrastructure mode v  base station connects

mobiles into wired network

v  handoff: mobile changes base station providing connection into wired network




ad hoc mode v  no base stations v  nodes can only

transmit to other nodes within link coverage

v  nodes organize themselves into a network: route among themselves



Illustration of a Cell

Illustration of a cell with a mobile station and a base station

BS

MS

Cell MS

Alternative shape of a cell

Ideal cell area (2-10 km radius)

Hexagonal cell area used in most models

20 20

Universal Cell Phone Coverage

Maintaining the telephone number across geographical areas in a wireless and mobile system

Microwave Tower

Cell

Cincinnati

Washington, DC


Wireless LAN and PAN

n  Wireless Local Area Network (LAN) using the IEEE 802.11

n  HiperLAN is a European Standard n  Wireless Personal Area Network (PAN)

n  Bluetooth n  HomeRF


Wireless Sensor Networks

Path of the Response

Radio Range

Data Collection and Monitoring Agency

Cloud of Smoke

Predicted position for the Cloud of Smoke

Path of the ResponsePath of the Response

Radio Range

Data Collection and Monitoring Agency

Cloud of Smoke

Predicted position for the Cloud of Smoke


Ad Hoc Network


Satellite Systems

n  Traditional Applications n  Weather satellite n  Radio and TV broadcasting n  Military satellites

n  Telecommunication Applications n  Global telephone connections n  Backbone for global network n  GPS


Wireless network taxonomy

single hop multiple hops

infrastructure (e.g., APs)

no infrastructure

host connects to base station (WiFi, WiMAX, cellular) which connects to

larger Internet

no base station, no connection to larger Internet (Bluetooth,

ad hoc nets)

host may have to relay through several

wireless nodes to connect to larger Internet: mesh net

no base station, no connection to larger Internet. May have to relay to reach other a given wireless node

MANET, VANET


Macrocell

Suburban

Coverage Aspect of Next Generation Mobile Communication Systems

Microcell

Urban

Satellite

Global

Global

Picocell

In-building

Challenges

27

Mobility Broadcasting Signal

Attenuation

Pros

Cons

Ubiquitous Access

Spatial Reuse

Cost Saving (CAPEX, OPEX)

Complex Management Interference Edge User

Effect Time-varying

Channel

- Inter-cell Coordination - QoS …

- Opportunistic scheduling - Rate adaptation - Error correction …

- MAC

- Mobile IP …

- RTS/CTS …

Hidden Node Problem

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