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Wireless Communication

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1 Wireless Communication
Background of Wireless Communication Wireless Communication Technology Wireless Networking and Mobile IP Wireless Local Area Networks Student Presentations and Projects Introductory Lecture

2 Objectives Where is Wireless Communication today? Where has it come from in the last decade? What is its future potential? Why is wireless channel different from wired? How does wireless design overcome the challenges of the channels and interference? What are key wireless communication concepts? Rapid fire introduction to buzz words and why they matter: OFDM/CDMA/MIMO … How do they feature in modern/emerging wireless systems (Wifi: a/b/g/n, 3G, mobile WIMAX: e)? Mobile Ad hoc and sensor networks are covered at the end of course …

3 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 1957 Advances in wireless technology Radio, television, mobile telephone, communication satellites More recently Satellite communications, wireless networking, cellular technology

4 Broadband Wireless Technology
Higher data rates obtainable with broadband wireless technology Graphics, video, audio Shares same advantages of all wireless services: convenience and reduced cost Services can be deployed faster than fixed services No cost of cable plant Service is mobile, deployed almost anywhere Wireless is convenient and less expensive

5 Limitations and Difficulties of Wireless Technologies
Limitations and political and technical difficulties inhibit wireless technologies Lack of an industry-wide standard Device limitations E.g., small LCD on a mobile telephone can only displaying a few lines of text E.g., browsers of most mobile wireless devices use wireless markup language (WML) instead of HTML

6 Part One: Chapter 1: Introduction
Provides preview and context for rest of the course Covers basic topics Data Communications TCP/IP

7 Chapter 2: Transmission Fundamentals
Basic overview of transmission topics Data communications concepts Includes techniques of analog and digital data transmission Channel capacity Transmission media Multiplexing

8 Chapter 3: Communication Networks
Comparison of basic communication network technologies Circuit switching Packet switching Frame relay ATM

9 Chapter 4: Protocols and the TCP/IP Suite
Protocol architecture Overview of TCP/IP Open systems interconnection (OSI) reference model Internetworking

10 Part Two: Wireless Communication Technology
Underlying technology of wireless transmission Encoding of analog and digital data for wireless transmission

11 Chapter 5: Antennas and Propagation
Principles of radio and microwave Antenna performance Wireless transmission modes Fading

12 Chapter 6: Signal Encoding Techniques
Wireless transmission Analog and digital data Analog and digital signals

13 Chapter 7: Spread Spectrum
Frequency hopping Direct sequence spread spectrum Code division multiple access (CDMA)

14 Chapter 8: Coding and Error Control
Forward error correction (FEC) Using redundancy for error detection Automatic repeat request (ARQ) techniques

15 Part Three: Wireless Networking
Examines major types of networks Satellite-based networks Cellular networks Cordless systems Fixed wireless access schemes Use of mobile IP and Wireless Access Protocol (WAP) to provide Internet and Web access

16 Chapter 9: Satellite Communications
Geostationary satellites (GEOS) Low-earth orbiting satellites (LEOS) Medium-earth orbiting satellites (MEOS) Capacity allocation

17 Chapter 10: Cellular Wireless Networks
Cellular wireless network design issues First generation analog (traditional mobile telephony service) Second generation digital cellular networks Time-division multiple access (TDMA) Code-division multiple access (CDMA) Third generation networks

18 Chapter 11: Cordless Systems and Wireless Local Loop
Wireless local loop (WLL) Sometimes called radio in the loop (RITL) or fixed wireless access (FWA)

19 Chapter 12: Mobile IP and Wireless Access Protocol
Modifications to IP protocol to accommodate wireless access to Internet Wireless Application Protocol (WAP) Provides mobile users access to telephony and information services including Internet and Web Includes wireless phones, pagers and personal digital assistants (PDAs)

20 Part Four: Wireless Local Area Networks
Examines underlying wireless LAN technology Examines standardized approaches to local wireless networking

21 Chapter 13: Wireless LAN Technology
Overview of LANs and wireless LAN technology and applications Transmission techniques of wireless LANs Spread spectrum Narrowband microwave Infrared

22 Chapter 14: IEEE 802.11 Wireless LAN Standard
Wireless LAN standards defined by IEEE committee

23 Chapter 15: Bluetooth Bluetooth is an open specification for wireless communication and networking Personal computers Mobile phones Other wireless devices

24 Wireless Ad hoc Networks
Wireless Ad hoc Networks is a specific type of Wireless networks when no infrastructure exists Multi-hop Ad hoc Networks Sensor Networks Routing Security Applications

25 Internet and Web Resources
Course Website Lectures, Labs, Assignments, Quizzes, Other Info Web page for the course text book web sites, errata sheet, figures, tables, slides, internet mailing list, wireless courses Computer Science Student Support Site Newsgroups comp.std.wireless comp.dcom.*

26 Text Books Wireless Communications and Networks, Second Edition
by William Stallings Fundamentals of Wireless Communication by David Tse and Pramod Viswanath

27 Wireless Communication: Potential

28 Why Wireless? Characteristics
Mostly radio transmission, new protocols for data transmission are needed Advantages Spatial flexibility in radio reception range Ad hoc networks without former planning No problems with wiring (e.g. historical buildings, fire protection, esthetics) Robust against disasters like earthquake, fire – and careless users which remove connectors! Disadvantages Generally very low transmission rates for higher numbers of users Often proprietary, more powerful approaches, standards are often restricted Many national regulations, global regulations are evolving slowly Restricted frequency range, interferences of frequencies Nevertheless, in the last years, it has really been a wireless revolution…

29 The Wireless Revolution
Cellular is the fastest growing sector of communication industry (exponential growth since 1982, with over 2 billion users worldwide today) Three generations of wireless First Generation (1G): Analog 25 or 30 KHz FM, voice only, mostly vehicular communication Second Generation (2G): Narrowband TDMA and CDMA, voice and low bit-rate data, portable units. 2.5G increased data transmission capabilities Third Generation (3G): Wideband TDMA and CDMA, voice and high bit-rate data, portable units Fourth Generation (in progress): true broadband wireless: WIMAX, 3G LTE, a/b/g/n

30 The Wireless Communication Opportunity
Demand Gap Wireless mobile services grew from 11 million subscribers worldwide in 1990 to over 2 billion in 2005. In the same period, the Internet grew from being a curious academic tool to about 1 billion users. Broadband internet access is also growing rapidly

31 Sept 2006 figures: 2.53 Billion total; 2.02 B (GSM), 320 M (CDMA), 81.2M UMTS

32 WLAN Market: WiFi WLAN Growth Drivers Convenience & Flexibility
Source: Pyramid Research WLAN Growth Drivers Convenience & Flexibility Productivity Gains Low Cost Embedded WLAN Source: AirTight Networks

33 Wireless: The Big Picture…

34 Wireless: Understanding the Big Picture…
Wireless (vs wired)… communication medium Cellular (vs meshed vs MANETs)… architectures for coverage, capacity, QoS, mobility, auto-configuration, infrastructure support Mobile (vs fixed vs portable)… implications for devices: phone vs PSP vs PDA vs laptop vs ultramobile WAN (vs WLAN vs WMAN)… network scope, coverage, mobility Market segments: Home networks, SOHO, SME, enterprise, Hotspots, WISPs, cellular … Technologies/Standards/Marketing Alliances: , UWB, Bluetooth, Zigbee, 3G, GSM, CDMA, OFDM, MIMO, Wimax…

35 Mobile Computing/Entertainment/Commns
iPoD: impact of disk size/cost Samsung Cameraphone w/ camcorder Computing: smaller, faster Disks: larger size, small form Communications: wireless voice, data Multimedia integration: voice, data, video, games SONY PSP: mobile gaming Blackberry: phone + PDA

36 Variety of Wireless-Capable Devices
2006 Thanksgiving sales: < $1000 Plasma 42” TVs. These will soon be wireless-broadband enabled and can play home movies/videos from the Internet

37 Emerging Rich Media Broadband Wireless
Broadband Wireless/Wireline LAN Cellular Rich Media Broadband Wireless Walled Garden Value Added Services Internet Access Services WiMAX stands at the intersection of the traditional walled garden cellular model and the open go anywhere do anything environment of the internet We believe this convergence will happen in devices as they are created to match the desired user experience  Personal Mobile Broadband – Anywhere, Anytime *Other brands and names are the property of their respective owners.

38 Converging Markets Drive Economies of Scale
CE devices will require low cost WLAN/WWAN access ~220M BB users (CBL+DSL+other) Market demand is >1B CE WLAN BWA 3GPP/2 250M devices in ‘09 with a need for access 200 M units a year growing at 35% >$1B market growing into cable and DSL markets $>600B market >2 B users >700M units/yr Converged Markets addressing Mobile WWAN 3G LTE/WiMAX WiFi The message is that all of these markets are focusing the WWAN subscribers WiFi/WiMax or WiFi/3G integration will bridge markets Source: Intel Estimates, IDC,

39 Mainstream Mobile Broadband Internet Will Also Require:
Innovation in Distribution: Single Chip WiFi + WiMAX/3G for Mass Market Innovation in Services: Web 2.0, AJAX, Personal Internet Innovation in Billing: Pay as You Go, Pre-paid, or Monthly Subscription * Other names and brands may be claimed as the property of others

40 Wireless History (Brief)

41 Wireless History 1924: First Mobile Radio Telephone
1901: First radio reception across the Atlantic Ocean 1924: First Mobile Radio Telephone

42 Early Cellular Systems
1940s-50s: cellular concept discovered (AT&T) 1st Generation: Analog: AMPS: FDMA with 30 KHz FM-modulated voice channels. 1983: The first analog cellular system deployed in Chicago: saturated by 1984, FCC increased the cellular spectral allocation from 40 MHz to 50 MHz. Two 25MHz channels: DL and UL (FDD) AT&T moved on to fiber optics in ‘80s. 2nd generation: digital: early 90s higher capacity, improved cost, speed, and power efficiency of digital hardware

43 Wireless Timeline (Partial)
Specification of DECT (cordless phone) Digital European Cordless Telephone (today: Digital Enhanced Cordless Telecommunications). Other cordless standards: PHS (Japan), CT-2 (Europe/Asia) MHz, ~ m range, 120 duplex channels, 1.2Mbit/s data transmission, voice encryption, authentication, up to several user/km2, used in more than 50 countries. Start of GSM In Germany as D1 and D2, fully digital, 900MHz, 124 channels Automatic location, hand-over, cellular Roaming in Europe - now worldwide in more than 170 countries Services: data with 9.6kbit/s, FAX, voice, ... HiperLAN (High Performance Radio Local Area Network) ETSI, standardization of type 1: GHz, 23.5Mbit/s Recommendations for type 2 and 3 (both 5GHz) and 4 (17GHz) as wireless ATM-networks (up to 155Mbit/s) Wireless LAN – IEEE IEEE standard, GHz and infrared, 2Mbit/s Already many (proprietary) products available in the beginning Specification of GSM successors UMTS (Universal Mobile Telecommunication System) as European proposals for IMT-2000 Iridium: 66 satellites (+6 spare), 1.6GHz to the mobile phone

44 Wireless Timeline (Partial)
Standardization of additional wireless LANs IEEE standard b, GHz, 11Mbit/s Bluetooth for piconets, 2.4Ghz, <1Mbit/s Decision about IMT-2000 Several “members” of a “family”: UMTS, cdma2000, DECT, … Start of WAP (Wireless Application Protocol) and i-mode Access to many (Internet) services via the mobile phone GSM with higher data rates HSCSD offers up to 57,6kbit/s First GPRS trials with up to 50 kbit/s (packet oriented!) GSM Enhancements for data transmission pick up (EDGE, GPRS, HSCSD) UMTS auctions/beauty contests Hype followed by disillusionment (approx. 50 B$ payed in Germany for 6 UMTS licenses!) Start of 3G systems Cdma2000 in Korea, UMTS in Europe, Foma (almost UMTS) in Japan 2002 – Standardization of high-capacity wireless networks IEEE as Wireless MAN

45 Broadband Wireless Milestones: Summary
Source: J.Andrews, A. Ghosh, R. Muhamed, Fundamentals of WIMAX

46 Wireless Systems: From Narrowband to Broadband

47 What do service providers need?
Highest possible consumer satisfaction… QoS is primary requirement – video and high throughput (mobile) data sessions Management capability to the devices: easy service provisioning, billing. Secure mobility support: Handoff & Mesh Avoid theft-of-service New services…

48 What do Home users want? Range: reliable wireless networking throughout the home High fidelity A/V: good Quality of Service for high quality audio and video Throughput! HDTV-720 in the 16 Mbps (MPEG2) HDTV-1080 in 20 Mbps (MPEG2) Next generation Media Center will support 2 concurrent video streaming, and by .11n ratification 4 concurrent streaming For 3 streams in the home, with picture-in-picture, and Internet access, 100Mbps UDP level throughput is easily consumed Self forming: a collection of access points to form a coherent & secure home network with minimal user intervention

49 Modern Wireless Systems

50 Modern Wireless Systems (by Segment)

51 IEEE Wireless Standards

52 Tradeoffs: Mobility/Coverage/BitRate

53 Wireless LANs: WiFi/802.11 Based on the IEEE a/b/g/n family of standards, and is primarily a local area networking technology designed to provide in-building or campus broadband coverage. IEEE a/g peak physical layer data rate of 54 Mbps and indoor coverage over a distance of 100 feet. Beyond buildings: municipal WiFi, Neighborhood Area Networks (NaN), hotspots Much higher peak data rates than 3G systems, primarily since it operates over a larger bandwidth (20 MHz). Its MAC scheme CSMA (Carrier Sense Multiple Access) is inefficient for large numbers of users The interference constraints of operating in the license-exempt band is likely to significantly reduce the actual capacity of outdoor Wi-Fi systems. Wi-Fi systems are not designed to support high-speed mobility. Wide availability of terminal devices 802.11n: MIMO techniques for range extension and higher bit rates

54 Wireless LAN Standards
802.11b (Current Generation) Standard for 2.4GHz ISM band (80 MHz) Frequency hopped spread spectrum Mbps, 500 ft range 802.11a (Emerging Generation) Standard for 5GHz NII band (300 MHz) OFDM with time division 20-70 Mbps, variable range Similar to HiperLAN in Europe 802.11g (New Standard) Standard in 2.4 GHz and 5 GHz bands OFDM Speeds up to 54 Mbps In 2006, WLAN cards have all 3 standards

55 IEEE 802.11n Over-the-air (OTA): 200 Mbps; MAC layer : 100Mbps
Rich content distribution- 3 HDTV quality streams and simultaneous broadband access; VoIP over WLAN supporting many simultaneous clients Service providers: microcells, neighborhood area networks (NANs) PHY MIMO/multiple antenna techniques Advanced FEC, (forward error correction) 10, 20 & 40Mhz channels widths Higher order modulation/coding MAC Flexible & efficient packet aggregation Legacy and channel width coexistence Power saving mechanisms Novel data flow techniques

56 WLAN Network Architecture
Basic Service Set (BSS): a set of stations which communicate with one another Infrastructure Mode Ad hoc network Only direct communication possible No relay function Stations communicate with AP AP provides connection to wired network (e.g. Ethernet) Stations not allowed to communicate directly Some similarities with cellular (covered later) Source: AirTight Networks

57 WLAN Network Architecture (2)
ESS: a set of BSSs interconnected by a distribution system (DS) Local Area Network (e.g .Ethernet) Future: Meshed Wireless Backhaul Source: AirTight Networks

58 Bluetooth: WPAN Cable replacement RF technology (low cost)
Short range {10m (1mW), 100m (100 mW)} Lower power than WiFi 2.4 GHz band (crowded) 1 Data (723.2 Kbps, reverse channel 57.6kbps: ACL) Or 3 synchronous voice channels (64kbps, SCO) Frequency-hopping for multiple access with a carrier spacing of 1 MHz for 8 devices per pico-net. 80 carriers => 80MHz. Collisions when multiple piconets nearby. Widely supported by telecommunications, PC, and consumer electronics companies. Hands free phone (ear set) for cars, internet chat/VoIP Intra-car networking announced by some car manufacturers in Europe. 8C Cimini-7/98

59 Q&A ?

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