History of wireless communication Simplified reference model

Wireless Communications

Introduction

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Topic of “Wireless Communication”

Ever wondered what really happened after, for example:

 Using a cellular phone to make a call while sitting in a train?

 Using the wireless local area network at Uni Koblenz-Landau?

How does data get from one mobile device to another, using wireless communication?

What communication systems and protocols are necessary to enable this functionality?

What are the challenges when communicating over wireless channels?

What are the challenges of networking nodes wirelessly?

Topic of “Wireless Communication”

This lecture treats wireless communications and networking

 From a modeling perspective (channels and whole networks)

 Useful for simulation and mathematical treatment

This lecture is about basic architecture and protocol mechanisms

 Attempts to give an overview of many important components

 For both local data communication and telecommunication

It is partially about specific technical solutions

 But tries to focus more on principles, as specific technical solutions come and go quite quickly

It will touch little the electrical engineering aspects of wireless communication

 some fundamentals are introduced

Wireless communication from a computer science and mathematical modeling of view

Computer science as a link between electrical engineering / physics and the applications

 In between lies the "protocol stack" with a large facet of computer science problems

System-oriented understanding

 Used hardware

 Physical properties (the wireless channel)

 Some vocabulary of electrical and communications engineering

 To enable you to look into an engineering book

 (e.g., look into the Rappaport to choose suitable simulation models)

Algorithmic understanding

 See lecture "Local Network Structures“

 The lecture "Local Network Structures" deals with algorithmic and graph-theoretical questions about locally organized networks

 Much of this are algorithmic questions about wireless (multihop) networks

Understanding of wireless networks from an analytic point of view

 See lecture on “Performance Evaluation of Wireless Networks”

 See lecture on “Random Communication Networks”

The world gets wireless: Moore’s Law

The world gets wireless: Exploiting Moore‘s Law wrt. Scale

Size Number

Computer for the next decades?

Computers are integrated

 small, cheap, mobile, interchangeable - no longer recognizable as an independent unit

Technology takes a back seat

 computers recognize where they are and adapt

 computers recognize where the user is and behave accordingly (e.g., forwarding calls, faxing)

Advances in technology

 higher computing power in a smaller space

 flat, lightweight, low-power displays

 new interfaces to the user due to small dimensions

 more bandwidth per cubic meter

 multiple wireless network interfaces: local wireless networks, global networks, regional telecommunications networks ...

Many things are moved into the cloud and needs to be accessed with

Are we facing an important problem? Yes

Largest networked system Largest number of subscribers

Mobile devices dominate the Internet Mobile applications dominate Internet

usage

Technology fully integrated into everybody's life almost 24/7, almost anywhere

And the future?

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Terms of mobile communication

Two aspects of mobility:

 User Mobility: The user communicates (wirelessly) "at any time, in any place, with anyone.“

 Device mobility: A terminal can be connected at any time, anywhere in the network.

Wireless vs. Mobile Examples

 

 

 

 

The desire for mobile data communication creates the need to integrate wireless networks into existing fixed networks:

 in the local area: standardization of IEEE 802.11, ETSI (HIPERLAN)

 in the Internet: the Mobile IP extension

 in the long-distance traffic: Connection to ISDN by GSM and further

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Wireless network types

Infrastructure-based

Infrastructure-less (ad-hoc)

Infrastructure nodes (Base station)

mobile/wireless device

Single hop

Multi hop

Wireless networks compared to fixed networks

Higher error rates due to interference

 Irradiation of e.g. electric motors, lightning

More restrictive regulation of frequency ranges required

 Frequencies have to be coordinated, the useful frequencies are almost all awarded

Lower transfer rates

 locally a few Mbit / s, regionally e.g. 53kbps with GSM / GPRS

Higher delays, larger fluctuations

 Connection setup times via GSM within seconds, otherwise a few hundred milliseconds

Less security against eavesdropping, active attacks

 Air interface is easily accessible for everyone, faked base stations

Always shared medium

 secure access procedures important

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Mobile end devices

P o w e r

pager

• only reception

• very small displays

• simple text messages

Mobile phones

• calls, data

• simple graphic displays PDA / Smartphone

• graphic displays

• Handwriting Recognition

• WWW

palmtops

• small keyboard

• simple versions of the standard programs

Laptop / Notebook

• fully functional

• standard applications

Sensors, embedded systems

Effects of end device portability

required power input

 limited computing power, lower quality of the displays, smaller secondary storage due to limited battery power

 CPU: Power consumption ~ V²f

 V: operating voltage, is continuously lowered (limits due to leakage currents)

 f: clock frequency, may e.g. be temporarily reduced

data loss

 must be planned from the outset (for example, defects, theft)

very limited user interface

 compromise between finger size and portability

 possibly integration of handwriting, language, symbols

limited memory

 Mass storage with moving parts only limited use

 Flash memory as an alternative

Other device types

Mobile devices are a subset of the devices with wireless interface In addition, infrastructure nodes with a wireless interface are often

required

 WiFi access points

 Base stations in mobile telephony

 Satellites for satellite communication systems

 Broadcasting stations for broadcast services (e.g., TV, radio)

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Applications I

Obvious applications

 Continuous connection to the Internet (and the usual services)

 mobile telephony

Traffic telematics (see picture on the next slide)

 Receiving news, road conditions, weather, music via DAB

 personal communication via GSM

 Positioning via GPS

 Local network with vehicles in the area to avoid accidents, control system, redundancy

 Vehicle data (e.g., by bus, ICE) can be forwarded to a workshop in advance, then faster repair

 An important ingredient for autonomous driving

Replacement of the wired infrastructure

 Replacement of the fixed infrastructure for earthquakes, fire etc.

Typical application: road traffic

UMTS, WLAN, DAB, DVB, GSM,

Cdma2000, TETRA, ...

Personal Travel Assistant, PDA, Laptop,

GSM, UMTS, WLAN, Bluetooth, ...

Applications II

Replacement of a landline

 deposited measuring stations, e.g. weather, river level

 networking historic buildings

Leisure, entertainment, information

 portable travel guide with up-to-date information on site

 ad hoc networks for multi-user games

Wireless sensor networks and

cyber-physical systems in general

Small embedded devices; no specific owner Equipped with sensors

With wireless communication capabilities

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Location dependent services

location awareness

 which services, such as printer, fax, telephone, server etc. exist in the local environment

follow services

 Transfer of the familiar desktop to the current location

information services

 "Push": e.g. current special offers in the supermarket

 "Pull": e.g. where do I find pizza with tuna

support services

 Caches, intermediate calculations, state information, etc. "follows" the mobile terminal through the fixed network

Outline

Motivation and conceptualization

 Content and relevance of the lecture

 The terms "mobile" and "wireless“

 Wireless networks from a bird's eye view

 Device types in fast forward

 Applications

 Location dependent services

 Open research topics

History of wireless communication Simplified reference model

Lecture Overview

Research areas in mobile communication

Wireless communication

 Transmission quality (bandwidth, error rate, delay)

 Modulation, coding

 media access

 ...

mobility

 Location dependent services

 Transparency of the location

 ...

portability

 required power input

 limited computing power, ad size, ...

 manageability

 ...

Wireless networks without infrastructure

 network organization

 data communication

 ...

Outline

Motivation and conceptualization

History of wireless communication

Simplified reference model

Lecture Overview

Inventions and discoveries

Early on, light was used for communication

 Flags ("semaphore"), pointer

 150 BC Smoke signals for communication;

from Polybius, Greece

 1794, Optical Telegraph, Claude Chappe

Here, above all, the use of radio is of interest:

 1831 Faraday demonstrates electromagnetic induction

 J. Maxwell (1831-79): Theory of electromagnetic fields, wave equations (1864)

 H. Hertz (1857-94): Experimentally demonstrates the wave character of electrical transmission

through space (1888 in Karlsruhe)

History of Wireless Communication I

1896 Guglielmo Marconi

 first demonstration of wireless telegraphy (digital!)

 Long wave transmission, high transmission power required (> 200kW)

1907 Commercial transatlantic connections

 very large base stations (30 100m high antenna masts)

1915 Wireless voice transmission New York - San Francisco 1920 Discovery of the shortwave transmission by Marconi

 smaller transmitters and receivers, made possible by the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben)

History of Wireless Communication II

1928 many field tests with TV (color TV, news, Atlantic) 1933 frequency modulation (E.H. Armstrong)

1958 A network in Germany

 analog, 160MHz, connection only from the mobile station, no handover, 80% coverage, 1971 11000 subscribers

1972 B network in Germany

 analogue, 160MHz, connection also from the landline (but the location of the mobile station must be known)

 also in A, NL and LUX, 1979 13000 participants in D

1979 NMT, 450 MHz (Scandinavia)

1982 Launch of the GSM specification

 Target: Pan-European digital mobile network with roaming

1983 Launch of the American AMPS (Advanced Mobile Phone System, analog)

1984 CT-1 Standard (Europe) for cordless phones

History of Wireless Communication III

1986 C network in Germany

 analog voice transmission, 450MHz, handover possible, digital signaling, automatic localization of the mobile station

 up to 2000 in use, services: FAX, modem, Datex-P, e-mail, 98% area coverage

1991 Specification of the DECT standard

 Digital European Cordless Telephone (today: Digital Enhanced Cordless Telecommunications)

 1880-1900MHz, ~ 100-500m range, 120 duplex channels, 1.2Mbps data transmission, voice encryption, authentication, several 10000 users / km2, usage in 50 countries

1992 Start of GSM

 in D as D1 and D2, full digital, 900MHz, 124 carrier frequencies

 automatic localization, handover, cellular,

 Roaming in Europe - now also in more than 200 countries worldwide

 Services: data at 9.6 kbit / s, FAX, voice, ...

History of Wireless Communication IV

1994 E-net in Germany

 GSM with 1800MHz, smaller cells

 as Eplus in D (at the end of 1997 98% of the population reachable)

1996 HiperLAN (High Performance Radio Local Area Network)

 ETSI, standardization of type 1: 5.15 - 5.30GHz, 23.5Mbps

 Suggestions for types 2 and 3 (both 5GHz) and 4 (17GHz) as wireless ATM extensions (up to 155Mbit / s)

1997 Wireless LAN - IEEE802.11

 IEEE standard, 2.4 - 2.5GHz and infrared, 2Mbit / s

 many proprietary products earlier

1998 specification of GSM successors

 UMTS (Universal Mobile Telecommunication System) as a European

 Proposal for IMT-2000 (IMT-2000: ITU Uniform Framework for Future Communication Systems)

Iridium

66 satellites (+6 reserve), 1.6GHz to the mobile phone

History of Wireless Communication V

1999 Further wireless LANs

 IEEE standard 802.11b, 2.4 - 2.5GHz, 11Mbps

 Bluetooth for piconets, 2.4GHz, <1Mbit / s Decision on IMT-2000

 Several "family members": UMTS, cdma2000, DECT, ...

Launch of WAP (Wireless Application Protocol)

 First start to merge internet / mobile communication

 Access to a variety of information services via a mobile phone

2000 GSM with higher transmission rates

 HSCSD offers up to 57,6kbit / s

 First GPRS installations with up to 50kbit / s (package-oriented) UMTS auctions

 Soaring and first disillusionment (over € 50 billion paid for 6 licenses)

2001 launch of 3G systems

 cdma2000 in Korea, UMTS tests in Europe, Foma (almost UMTS) in Japan

History of wireless communication VI

2002

 WLAN hot spots start to spread

2003

 UMTS starts in Germany

 Start of DVB-T in Germany replacing analog TV

2005

WiMax starts as DSL alternative (not mobile)

first ZigBee products

2006

HSDPA starts in Germany as almost UMTS download version offering> 3 Mbps

WLAN draft for 250 Mbps (802.11n) using MIMO

WPA2 mandatory for Wi-Fi WLAN devices

2007

over 3.3 billion subscribers for mobile phones (NOT 3 bn people!)

2008

"Real" Internet widely available on mobile phones (standard browsers, decent data rates)

7.2 Mbps HSDPA, 1.4 Mbps HSUPA available in Germany, more than 100 operator support HSPA worldwide, first LTE tests (> 100 Mbps)

2009 the story continues with netbooks, iPhones, VoIPoWLAN ...

2010 LTE available in some cities, new frequencies allocated

Reuse of old analogue TV bands, LTE as DSL replacement for rural areas

2010 4G and now 5G

Mobile radio systems: development at a glance

mobile phone satellites cordless wireless LAN

phones

1992:

GSM 1994:

DCS 1800

2001:

IMT-2000

1987:

CT1+

1982:

Inmarsat-A

1992:

Inmarsat-B Inmarsat-M

1998:

Iridium

1989:

CT 2 1991:

DECT 199x:

proprietary 1997:

IEEE 802.11 1999:

802.11b, Bluetooth 1988:

Inmarsat-C

analog digital

1991:

D-AMPS 1991:

CDMA 1981:

NMT 450

1986:

NMT 900

1980:

CT0

1984:

CT1 1983:

AMPS

1993:

PDC

2000:

GPRS 2000:

IEEE 802.11a

Today:

Fourth Generation (Internet based)

Outline

Motivation and conceptualization History of wireless communication

Lecture Overview

Reference model (simplified)

Application Transport

Network Link Physical

Link Physical

Application Transport

Network Link Physical Link

Physical

Network Network

Influence of mobile communication on the reference model

 service location

 new applications, multimedia

 adaptive applications

 congestion control, flow control

 quality of service

 addressing, routing, terminal localization

 handover

 authentication

 media access

 multiplexing

 Media access control

 encoding

 modulation

 interference

 attenuation

 frequencies

application layer

transport layer network layer data link layer

physical Layer

Outline

Motivation and conceptualization History of wireless communication Simplified reference model

Lecture Overview

General Overview

technical basics media access control telecommunications

systems

ad-hoc and sensor networks

wireless LANs network protocols

transport protocols

Tentative list of topics

 introduction

 scenarios

 definitions

 challenges

 All preliminaries you need for a full understanding

 technical basics

 Wave propagation, frequencies

 Signals, attenuation, antennas

 modulation

 media access

 SDMA, TDMA, CDMA, FDMA

 CSMA / CA, Aloha with variants

 Collision avoidance, polling

 sensor networks

 applications

 challenges

 energy efficient MAC layer

 determination of location and



Wireless telecommunications systems

 e.g. GSM, HSCSD, GPRS, DECT, TETRA, UMTS, IMT- 2000



Wireless LANs

 Techniques, applications

 IEEE 802.11a / b / g, .15, Bluetooth



Network Protocols

 Mobile IP

 Ad-hoc networks

 routing



Transport Protocols / Mobile TCP

 reliable data transport

 flow control

 quality of service

Summary

Motivation and conceptualization History of wireless communication Simplified reference model

Lecture Overview

Summary

Wireless communication is an extremely important building block in modern IT

 hardware trends

 user expectations

Wireless communication is not solved by small adjustments of wired communication

There is not one wireless communication scenario

 used device types

 use cases

 many different network types

Two main challenges from a technical point of view

 integration into existing networks

 development of new network organization forms